YORK MILLS COLLEGIATE INSTITUTE SCIENCE DEPARTMENT Jim Henson’s Muppets © Grade 11 Chemistry University Level SCH3U - ____ STUDENT WORKBOOK For the school year: 2018 - 2019 Name: _________________________________________________ 1 TABLE OF CONTENTS Table of Contents.............................................................................................................................................................................. 2 Course Outline: Grade 11 Chemistry – University (SCH3U) ........................................................................................................... 4 Safety Rules in the Chemistry Lab.................................................................................................................................................... 6 Basic Rules for Multiple Choice Questions ....................................................................................................................................... 7 Lab Outline & Lab Format ................................................................................................................................................................. 8 Significant Digit Rules ..................................................................................................................................................................... 10 Problem Solving Format ................................................................................................................................................................. 12 Writing Study Notes ........................................................................................................................................................................ 13 Matter, Chemical Trends & Chemical Bonding ............................................................................................................................... 14 Atomic Notation............................................................................................................................................................................... 14 Isotope Problems ............................................................................................................................................................................ 14 Variation in Atomic Properties ......................................................................................................................................................... 15 Electronegativity & Types of Intramolecular Bonding ..................................................................................................................... 15 Ionic Bonding .................................................................................................................................................................................. 15 Covalent Bonding............................................................................................................................................................................ 16 VSEPR Structures & Polarity .......................................................................................................................................................... 16 Chemical Reactions Unit................................................................................................................................................................. 17 Chemical Nomenclature of Ionic Binary Compounds ..................................................................................................................... 17 Chemical Nomenclature of Multivalent Compounds ....................................................................................................................... 17 Chemical Nomenclature of Simple Polyatomic Compounds ........................................................................................................... 17 Chemical Nomenclature of More Polyatomic Compounds ............................................................................................................. 18 Chemical Nomenclature of Acidic & Basic Compounds ................................................................................................................. 18 Chemical Nomenclature of Covalent Binary Compounds ............................................................................................................... 18 Chemical Nomenclature Review ..................................................................................................................................................... 19 Balancing Skeleton Equations ........................................................................................................................................................ 19 Balancing Word Equations.............................................................................................................................................................. 20 Identifying Types of Reactions ........................................................................................................................................................ 20 Combustion, Synthesis & Decomposition Reactions ...................................................................................................................... 20 Single Displacement Reactions ...................................................................................................................................................... 21 Double Displacement Reactions ..................................................................................................................................................... 21 Net Ionic Equations ......................................................................................................................................................................... 21 Quantities in Chemical Reactions Unit............................................................................................................................................ 21 Molar Mass Problems ..................................................................................................................................................................... 21 Avogadro’s Number Problems ........................................................................................................................................................ 22 Mole Related Problems (# of Particles) .......................................................................................................................................... 22 Mole Related Problems (# of Moles)............................................................................................................................................... 22 Mole Related Problems (Advanced Calculations) ........................................................................................................................... 23 % Composition Problems (from Chemical Formulas) ..................................................................................................................... 23 % Composition Problems (from Experiment) .................................................................................................................................. 23 Simplest Formula Problems ............................................................................................................................................................ 24 Molecular Formula Problems .......................................................................................................................................................... 24 Hydrate Problems ........................................................................................................................................................................... 24 Simple Stoichiometry Problems (mol-mol) ...................................................................................................................................... 25 Excess Reagent/Reactant Mass-Mass Stoichiometry Problems .................................................................................................... 25 Limiting Reagent/Reactant Stoichiometry Problems ....................................................................................................................... 26 Stoichiometry Review Problems ..................................................................................................................................................... 26 % Yield Problems............................................................................................................................................................................ 27 % Purity Problems .......................................................................................................................................................................... 27 Solutions & Solubility Unit ............................................................................................................................................................... 28 Determining Solubility ..................................................................................................................................................................... 28 Concentration Unit Conversions ..................................................................................................................................................... 28 Concentration Formula Problems ................................................................................................................................................... 28 Molar Concentration Problems ....................................................................................................................................................... 29 Dilution Problems ............................................................................................................................................................................ 29 Solutions & Solubility Problems ...................................................................................................................................................... 30 2 Solubility Problems ......................................................................................................................................................................... 30 Solution Stoichiometry Problems .................................................................................................................................................... 31 Conjugate Acids & Bases ............................................................................................................................................................... 32 pH Calculations ............................................................................................................................................................................... 32 pH & pOH Calculations ................................................................................................................................................................... 32 pH & Strong Acid Problems ............................................................................................................................................................ 33 Strong Acid & Strong Base Titration Problems ............................................................................................................................... 33 Strong Acid & Strong Base Neutralization Problems ...................................................................................................................... 33 Gases & Atmospheric Chemistry Unit............................................................................................................................................. 34 Pressure & Temperature Conversions............................................................................................................................................ 34 Boyle’s Law Problems..................................................................................................................................................................... 34 Charles’ Law Problems ................................................................................................................................................................... 35 Gay-Lussac’s Law Problems .......................................................................................................................................................... 35 Combined Gas Law Problems ........................................................................................................................................................ 35 Ideal Gas Law Problems ................................................................................................................................................................. 36 Ideal Gas Law Molar Volume Problems.......................................................................................................................................... 36 Ideal Gas Law Molar Mass Problems ............................................................................................................................................. 37 Ideal Gas Law Density Problems .................................................................................................................................................... 37 Gas Stoichiometry Calculations ...................................................................................................................................................... 37 Dalton’s Law of Partial Pressures Problems ................................................................................................................................... 38 Water Vapour Pressure Problems .................................................................................................................................................. 38 Reference Material.......................................................................................................................................................................... 39 Conversion Factors for Calculations ............................................................................................................................................... 39 Constants ........................................................................................................................................................................................ 39 Useful Formulas .............................................................................................................................................................................. 39 Useful Polyatomic Ions ................................................................................................................................................................... 40 Metal & Halogen Activity Series ...................................................................................................................................................... 40 Solubility Table @ SATP................................................................................................................................................................. 40 Water Vapour Pressure Table ........................................................................................................................................................ 41 Periodic Table ................................................................................................................................................................................. 42 Last revised: August 20, 2018 3 COURSE OUTLINE: GRADE 11 CHEMISTRY – UNIVERSITY (SCH3U) Chemistry Teachers: E. Lindala, A. Salloum Phone: 416-395-3340 x 20125 Text: Jenkins, F., H. Van Kessel, L. Davies, O. Lantz, P. Thomas, D Tompkins, M. DiGiuseppe. 2002. Chemistry 11. Nelson Publishers, Toronto. Prerequisite: SNC2D Course Description: This course enables students to deepen their understanding of chemistry through the study of properties of chemicals & chemical bonds; chemical reactions & quantitative relationships in those reactions; solutions & solubility; & atmospheric chemistry & the behaviour of gases. Students will further develop their analytical skills & investigate the qualitative & quantitative properties of matter, as well as the impact of some common chemical reactions on society & the environment. Emphasis will also be placed on the importance of chemistry in other branches of science. Units of Study: 1. Matter, Chemical Trends & Chemical Bonding 2. Chemical Reactions 3. Quantities in Chemical Reactions 4. Solutions & Solubility 5. Gases & Atmospheric Chemistry Evaluation Outline: TERM WORK: Knowledge/Understanding Application Communication Thinking 70 30 100 Total – Term Work SUMMATIVE EVALUATION: COURSE TOTAL: 30 (± 5) 15 (± 5) 15 (± 5) 10 (± 5) Final Exam Policies & Expectations: 1. Attendance is critical for success in this course & the school attendance policy will be adhered to. If a test or assignment due date is missed, inform your teacher in advance and provide documentation indicating that the student is unable to attend school for the day & time the test or assignment is due, & acknowledge that the test/assignment is being missed. The test/assignment will be accommodated when the student returns to school, at the teacher’s convenience. 2. An assignment cannot be handed in for marking after the same marked assignment has been returned. All assignments are due at the beginning of class. Late marks may be deducted. 3. Students are expected to come prepared to each class, with their course notes, student workbook, calculators, periodic tables & other reference sheets as required. 4 4. Students are expected to do approximately 30 minutes of homework (on average) following every class. The actual amount will depend on how much is accomplished during class time. Through much of the course, understanding new concepts will depend on previous concepts & homework. 5. Plagiarism is cheating. Any copied work in which the source is not correctly cited is plagiarism, whether the source is a book, the Internet, or another students’ work. All plagiarized work will receive a mark of zero, with no opportunity to resubmit the assignment. In addition, the student’s name will be entered into the plagiarism registry, in accordance with the school plagiarism policy. 6. Students in need of extra help are encouraged to ask for this help when needed. Please make an appointment at a time that is mutually convenient for both the teacher & student. Extra help should not be expected on the day of a formally announced evaluation. Students should be prepared to ask specific questions, e.g. question ## on page ##. 7. On occasion, it will be required for students to email an electronic copy of work as part of their evaluation. 8. A complete version of the Course Outline for SCH3U can be found at: http://schools.tdsb.on.ca/yorkmillsci/ 5 SAFETY RULES IN THE CHEMISTRY LAB As a chemistry student, you MUST read & follow the instructions below: 1. Lab behaviour must be safe, calm & focussed at all times during a lab. 2. Eye protection must be worn over your eyes when directed by the teacher. 3. Be familiar with the location & use of safety equipment in the classroom & of the hazard information for all the chemicals being used. 4. Report all accidents to the teacher at once, no matter how minor. 5. Report broken, damaged or defective equipment & unidentified chemicals to the teacher. 6. Place all cracked or broken glassware in the broken glass container at the front of the room. 7. Use separate scoopulas for separate chemicals. 8. Take only the amount of chemical needed & transport it in a safe container between the supply bench & your work area. 9. Replace all container lids immediately after use. 10. Keep hands, scoopulas, pens, pencils, etc., away from your mouth 11. Leave all food out of the lab. During a lab, water bottles must also be left outside. 12. Maintain an uncluttered work area—the only things that should be at the lab bench are the lab outline, a pen & your lab notebook/report. 13. Remain standing while performing any experiment. 14. Clean your lab area before leaving, including washing & putting away equipment & removal of all solids from sinks & drains. 15. Beware of any liquids or solids on the lab benches—they may be corrosive. 16. Ensure that you understand the safe procedure to be followed before attempting any experiment. 17. Wash hands thoroughly after lab work. In any lab exercise, safety is the first priority & is the responsibility of every individual in the room. The purpose of these safety rules is to ensure a safe environment for everyone & it is extremely important that they are followed during a lab. Students who do not comply with these safety rules will be asked to leave & will receive a zero on the assignment/lab. 6 BASIC RULES FOR MULTIPLE CHOICE QUESTIONS Here are some suggestions on improving your multiple choice testing skills. 1. Read the question & try to answer it BEFORE looking at the answers By thinking of the answer first, you are less likely to be fooled by a wrong answer Read through all the answers before choosing…the best answer is not always the first correct answer you see For example: Toronto can be described as Ontario’s a. Capital city b. Largest city c. Most multicultural city d. All of the above e. None of the above 2. Do not spend too much time on any one question Sometimes the question will seem to have no right answer…your teacher may have made a mistake. There may not be a right answer. It is important not to waste too much time trying to answer an impossible question. Choose an answer at random, but circle the question number so that you can come back to it later if you have extra time. Similarly, if a question is too hard, or you just do not know the answer, choose an answer at random & come back when you have completed all the questions you do know. Use whatever time is left over at the end of the test to tackle these very difficult questions For example: The capital of Ontario is a. Markham b. Mississauga c. Pickering d. Richmond Hill e. Windsor 3. …the answer is (d) …there is no correct answer If the question asks you something you do not know, see if you can cross out any of the wrong answers before you guess If you eliminate answers you know are incorrect, you increase your chances of getting it right, just by guessing For example: The capital of British Columbia is a. Edmonton b. Ottawa c. Vancouver d. Victoria e. Winnipeg …answer is (d) 4. Do not keep changing your answer. Research shows that your first choice was probably the right one. Most people who change their answers will change from a correct one to a wrong one. Only change your answer if you are absolutely sure you made a mistake. (For example, if another question on the test reminds you of the right answer) 5. After you have finished the test, go back to those questions you circled as being too hard or as having no right answer Do not finish a test early unless you are sure you have answered everything to the best of your ability. Do not leave any questions blank 7 LAB OUTLINE & LAB FORMAT All labs must be formatted as follows, with numbers 1 to 3 completed before the first lab: 1. All pages must be in (water insoluble) ink pen (preferably blue). 2. The date & title of the lab must head the first page of each lab. 3. All notations, including tables, observations, calculations & diagrams, must be made with pen only. All written sections should be single-spaced. 4. Nothing should be whited out. If you want to make a change, draw a line neatly through the work to be changed & rewrite it. 5. Only one side of the page should be used for the lab. EVALUATION The lab component of this course is 15% ±5%. You will be evaluated as follows: for each lab, you will receive a performance mark based on preparedness, performance, understanding & safety considerations each lab will be submitted for marking for format & content—not every part of every lab will be marked time permitting, there may be one formal lab write-up based on your notes **A NOTE ABOUT PLAGIARISM** As with any written work, it is considered plagiarism to copy work from another student, or to allow your work to be copied. While it is acceptable to work with a partner on the lab, you must write every part of your lab report independently. You are each expected to hand in your own work, with the report written in your own words. Copied lab reports will be given a mark of 0. Lab Format For every lab, a pre-lab must be completed before you arrive to the lab class; the pre-lab (purpose, introduction, chemical hazards, method/procedure) will be checked at the beginning of the lab, & will count towards your lab mark. In general, lab reports must be written in passive tense, with most sections are in past passive tense. Lab reports also have the same format with the following headings & sections: PURPOSE • the purpose of the lab must be clearly stated, usually in point form INTRODUCTION • must be written as a paragraph, using complete sentences (about 5-6 sentences) • begins with a description & explanation of the concept of the lab • must include any special safety considerations at the end of the introduction CHEMICAL HAZARDS • a brief table (½ page maximum) containing the relevant health & first aid information for the lab’s major chemicals • the information may be obtained from on-line MSDS (Material Safety Data Sheets) METHOD/PROCEDURE 1. Consists of a flowchart showing how to do the lab • a long vertical arrow (or series of arrows), drawn with a ruler, represents the order of events • substances added are shown by a labeled arrow flowing into the main arrow from the side • anything done to the experimental mixture is labeled beside the main arrow in a location appropriate to the time at which it is done (see example below) • if components of the mixture are separated &/or treated differently, branches must split off the main arrow in the appropriate spot Materials/Equipment Actions Taken 100 mL beaker Added 10.0 mL of water Added 1.00 g salt Stirring Rod Stirred contents in beaker 8 2. Includes a diagram of any relevant apparatus or set-up • all diagrams should be neatly drawn & labeled—use a ruler & avoid sketches • diagrams are 2-dimensional figures • each diagram must have a number & a descriptive title (i.e., Figure 1: Distillation Apparatus) Burette Stopcock Retort Stand Sample in Beaker Figure 1: Setup of a Titration OBSERVATIONS • must include qualitative observations, in table form or in a series of point-form statements • table format (see below) must be used if substances are being compared • observations must follow the order of the procedure • must include any quantitative observations, including all raw data (every measurement) organized into a table • all tables must have a border, & lines separating columns & rows • each table must have a number & a descriptive title (i.e., Table 1: Observations of Esters) • rows & columns must be used logically & appropriately to organize the data • for any calculated values included in a table, a sample calculation should be provided below the table Table 1: Measurements of Length & Width Object Length (m) Width (m) RESULTS/ANALYSIS • may include calculations • correct problem-solving format & significant digits are required • a heading must be used to indicate what is being determined • if a series of calculations of the same type are being done, show one sample calculation & give the answers for the rest • may include balanced chemical equations &/or graphs • correct graphing format must be used • graphs may be completed on a computer & attached into the lab book • every graph must have a number & descriptive title (i.e., Figure 1: Concentration of Iodine Solution) • any questions in this section should be answered separately & in order, & the questions themselves should NOT be copied from the lab sheet DISCUSSION • consists of answers to lab questions • should be answered separately & in order • written in complete, correct sentences which clearly indicate what the question was • questions from the lab sheet should NOT be copied into the lab report • must include reference to appropriate results where required • state table or figure number & data or observation that supports the answer to the question • usually requires thorough analysis of the data presented in the Results section • avoid “human error” in error analysis & focus on the assumptions made in the lab 9 EXPERIMENTAL ERROR IS NOT THE SAME AS HUMAN ERROR! • Experimental error is unavoidable! As you do your lab, consider the following: • Assuming the technique is correct, what errors are associated with the lab or concept behind the lab • Are there any side reactions? (be specific!) • Why do the experimental values do not match the “real” answer? • Human error definition: “a source of error that can be avoided” (i.e., spillage, etc) …in summary: if you can do something about it, it is a human error, if you can’t avoid it, it is experimental error CONCLUSION • consists of one or two sentences with reference to the purpose of the lab • should make specific reference to the significant result that addresses the purpose SIGNIFICANT DIGIT RULES Significant digits/figures (sig digs/figs) represent a degree of precision or accuracy in scientific measurements. The limitations on precision must be reflected in calculations by using the appropriate number of significant digits. For example, on a mass balance, mass can only be measured to 2 decimal places. We can measure 1.98 g (3 sig digs) of Na2CO3, but not 1.975 g (4 sig digs) of Na2CO3. Counting Significant Digits: In order to use significant digits accurately, you need to know which digits are significant! If you are dealing with scientific notation, count the digits in the first part. 1. All non-zero digits are significant this means 68.3 mL has 3 sig digs & 165.35 cm has 5 sig digs 2. Zeroes that have non-zero digits on either side are significant this means 307.5 L has 4 sig digs & 20.004 m have 5 sig digs 3. Zeroes at the beginning of a number are not significant, because these zeroes are only placeholders this means both 0.0265 mm & 0.0000265 mm both have 3 sig digs 4. Zeroes at the end (right side) of a number are significant if they appear after a decimal, otherwise they are insignificant this means 1.5000 km has 5 sig digs but 15000 km has only 2 sig digs Rules for Using Significant Digits: 1. When multiplying or dividing measured values, the answer should be expressed with the same number of significant digits as the data with the lowest number of significant digits. 2. When adding or subtracting, the answer should be expressed with the same number of decimal places as the data with the least number of decimal places. 3. Some numbers are exact. For example, counted objects such as people, pens & calculators are considered to have an infinite number of significant digits. This is because counting is not limited by a measuring device. 4. For all calculations, it is safer to carry at least ONE extra significant digit until you complete the final calculation. Rounding too far too soon can lead to a significant impact on your answer. 5. Significant digits involving logarithms require a slightly different set of rules. See section below. Example: Suppose a group of students had to measure the dimensions of a box for the purpose of finding the total surface area. The measurements were found to be: 1.1 m, 289 cm, 1500.5 mm. Show all your work. 10 l = 1.1 m w = 289 cm = 2.89 m h = 1500.5 mm = 1.5005 m SA = 2lw + 2lh + 2hw SA = 2(1.1)(2.89) + 2(1.1)(1.5005) + 2(2.89)(1.5005) SA = 18.33199 m2 18 m2 the surface area was 18 m2. Notice the length has 2 sig digs whereas the width & height have 3 & 4 sig digs, respectively…the final answer should be reported using the same number of significant digits as the data with the least number of significant digits, in this case, 2 sig digs. There is no value in saying it represents 18.33199 m2 (7 sig digs) because the precision of the initial measurements were limited. This means we can only claim our calculated answer is as accurate as the least accurate measurement, & we do this by reporting our final answer to the same number of significant digits as our least precise measurement. The objective, when dealing with the quantitative aspects of science, is to be as accurate as possible within the limitations of our data. Therefore, it is extremely important to use significant digits correctly. Significant Digits & Logarithms (pH Calculations): When calculating the pH of a concentration (or vice versa), the number of significant digits in the concentration should equal the mantissa (the number of significant digits to the right of the decimal place) in the pH value. Note the underlined values in the following examples: pH = -log (1.234 x 10-12) = 11.90868484 11.9087 4 significant digits in the value 1.234 x 10-12 means 4 significant digits in the mantissa of the pH pH = -log (0.0012) = 2.900818754 2.90 2 significant digits in the value 0.0012 means 2 significant digits in the mantissa of the pH [H+] = 10-pH = 10-1.951 = 0.011194378 mol/L 0.0112 mol/L 3 significant digits in the mantissa of the pH means 3 significant digits in the concentration [H+] = 10-pH = 10-10.32 = 4.786300923 x 10-11 mol/L 4.8 x 10-11 mol/L 2 significant digits in the mantissa of the pH means 2 significant digits in the concentration The whole number in a pH value is not included in the significant digit count because it indicates the location of the decimal point. Note the following example: [H+] = 10-pH = 10-9.87 = 10-0.87 x 10-9 = 0.134896288 x 10-9 mol/L = 1.34896288 x 10-10 mol/L 1.3 x 10-10 mol/L 11 PROBLEM SOLVING FORMAT Chemistry is a cumulative subject, & much of the quantitative analysis in chemistry requires cumulative skills. Many chemistry problems require a series of calculations & conversions in the solution. Use of a logical, consistent problem solving strategy is important for many reasons: it helps with analysis of the problem & therefore directs the solution to the problem it ensures clarity in the communication of the solution it provides a tool by which errors can be isolated & corrected Therefore, in solving quantitative problems encountered in this course, the process is more significant than the actual numerical value in the solution. All problems, even simple ones, provide an opportunity to practice using a logical & consistent strategy. With few exceptions, solutions to problems must include the following: 1. Given Information this constitutes the initial analysis of the problem all quantitative information for the problem is listed neatly, with symbols & units (all numerical values must be accompanied by a unit) any unknown quantities that are asked for or implied in the problem are also listed 2. Formula or Clearly Defined Conversion Factors this shows the strategy chosen in order to solve the problem 3. Substitution & Answer this is the actual process of manipulating the data to arrive at a final value communication is important here, so steps must be clearly indicated & units must be included the final answer must reflect the correct number of significant digits (usually 2 to 4 significant digits) 4. Statement this answers the question posed in the problem if the answer is not the numerical value from the calculation every question must end with a concluding statement, even if it consists of a brief sentence Example: A ball is dropped from a height of 2.0 m. It rebounds one-half the distance on each bounce. What is the height the ball will reach after the 2nd bounce? Solution: Initial height = yo = 2.0 m b=½ n=2 y=? y = yo(b)n y = 2.0m(½)2 y = 0.50 m the ball would reach 0.50 m after the 2nd bounce. 12 WRITING STUDY NOTES Writing study notes should not be difficult nor a big task. Study notes consist of important points that should be remembered. This usually includes worked out examples/questions. Although everybody’s set of study notes will be different, there are some points you should follow when creating study notes: Keep it short (2 – 5 pages maximum…the better you can reword & condense, the more you remember) Include worked out solutions to 2 or 3 important problem types (include call-outs to important parts where you can go wrong)…again, the fewer the number of worked out problems, the more you realize that there isn’t much material to learn/remember Keep it organized (use headings, tables & strategic use of colour to help organize your information) Space is important! A wall of text is difficult to study from! Handwrite your study notes (studies have shown that the more times you write something, the better you assimilate the information…also, handwriting allows you to write just about anywhere on a page without worrying about formatting problems that typing gives) Keep it relatively neat & legible (slight messiness is acceptable, but remember that the easier it is to read, the more useful your study notes become at a future time, such as before an exam!) What NOT to do when writing study notes: Do NOT recopy your class notes…reword & use different examples!...design as if you were teaching someone else How to Grade Study Notes: Although everyone’s study notes will be different, all good study notes have similar qualities: Level 1 Content (x 1) Organization, Colour & Neatness (x 1) Length (x 0.5) Level 2 Work is incomplete Work is recopied from class notes Sequence of information is difficult to follow; work is illegible, no colour Difficult to follow work because of organization, indiscriminate use of colour/no colour Less than 2 pages or more than 5 pages Total Level 3 Work is reworded, using different examples, without detail (no callouts) Work presents information in a relatively neat & logical sequence, used colour Level 4 Work is reworded, using different examples, with full detail (with callouts) Information in logical sequence which is neat & can be easily followed, strategic use of colour Points Between 2 & 5 pages /10 13 MATTER, CHEMICAL TRENDS & CHEMICAL BONDING ATOMIC NOTATION 1. Define the following terms: a. atomic number 2. For each of the 3 subatomic particles, answer the following: a. Where is it located in the atom? b. What is its mass? c. What is the relative mass of particle (in comparison to the smallest subatomic particle)? 3. Identify the elements which have the following numbers of protons in the nuclei of their atoms: a. 7 b. 29 c. 47 b. mass number c. isotope 4. How many protons are in the atom of each of the following elements? a. Boron (B) d. Calcium (Ca) b. Lead (Pb) e. Silicon (Si) c. Uranium (U) f. Iron (Fe) 5. Write the atomic notation for a neutral atom with the following: a. 8 protons, 9 neutrons c. 1 proton, 1 neutron b. 6 protons, 8 neutrons d. 45 neutrons, 35 electrons 6. 7. d. g. h. i. Oxygen (O) Helium (He) Zinc (Zn) e. 12 neutrons, 12 electrons Determine the number of protons, electrons & neutrons for the following: a. 25Mg c. 80Br e. 35P 3 37 d. 201Hg f. Cl b. 56Co Name the neutral element & give the atomic notation for each when: a. Z = 7 & A = 14 b. Z = 10 & A = 20 c. Z = 17 & A = 37 90 g. h. d. 3 H 55 Mn 7 Z = 26 & A = 56 ISOTOPE PROBLEMS 1. Natural potassium consists of 93.1% K-39 & 6.90% K-41. What is the average atomic mass of natural potassium? (39.1 u) 2. Thallium consists of 29.50% Tl-203 & 70.50% Tl-205. Calculate the average atomic mass of thallium. (204.4 u) 3. Neon consists of 90.92% Ne-20, 0.2600% Ne-21 & 8.820% Ne-22. What is the average atomic mass of neon? (20.18 u) 4. Erbium consists of 33.41% Er-166, 22.94% Er-167, 27.07% Er-168 & 16.58% Er-170. What is the average atomic mass of erbium? (167.4 u) 5. Mercury has 26 isotopes, but the 7 important ones with their corresponding percentage abundances are: Hg-196 0.1400% Hg-200 23.13% Hg-204 Hg-198 10.02% Hg-201 13.22% Hg-199 16.84% Hg-202 29.80% What is the average atomic mass of naturally occurring mercury? (200.6 u) 6.850% 6. Gallium has two isotopes. If the two isotopes are: Ga-69 (68.95 u) & Ga-71 (70.95 u), find the isotopic abundances of each isotope. (61.50% & 38.50%) 7. Natural argon has three isotopes: Ar-36 (35.967 u), Ar-38 (37.962 u) & Ar-40 (39.962 u). If the isotopic abundance of Ar-36 is 0.006000%, find the isotopic abundances of the other two isotopes. (0.588% & 99.406%) 14 VARIATION IN ATOMIC PROPERTIES 1. Define effective nuclear charge. 2. Explain the trend for the effective nuclear charge across a given period. 3. Discuss the effective nuclear charge for the elements carbon, silicon & germanium. 4. For each pair of elements indicate & then explain which element has the greater atomic size: a. Na or K b. Na or Mg c. O or S For each pair of elements, explain which element has the greater ionization potential energy: a. Na or K b. Na or Mg c. O or S 6. For each pair of elements, explain which element has the greater electron affinity: a. O or S b. O or F c. F or Ne 7. For each pair, indicate which element would be the more reactive. Explain in terms of either the ionization energies or electron affinities of the elements: a. Na or K b. Na or Mg c. O or F 8. Explain what happens when you go down a group in the periodic table to: a. The atomic size The ionization energy 5. The electron affinity ELECTRONEGATIVITY & TYPES OF INTRAMOLECULAR BONDING Determine whether the bond that would occur between the following pairs of elements is ionic or covalent. For each polar covalent bond, label the atom that is slightly positive & slightly negative with the symbols + & -, respectively. 1. H & I 4. H & F 7. Mg & O 10. Mg & H 2. Li & Br 5. C & S 8. Ca & S 11. Si & B 3. P & H 9. K & F 6. Al & I IONIC BONDING 1. Each of the following pair of elements forms an ionic compound. For each pair, draw a Lewis diagram to show how each are bonded to each other & write the ionic formula: c. Ga & F e. Na & O a. Li & Cl f. Ca & F d. Al & F b. K & S 2. Ionic compounds always have relatively high melting points. What information does this give you concerning the strength of the ionic bond? Explain. 3. Oxygen & chlorine do not react by producing an ionic bond. Why not? 4. Potassium metal (composed of atoms) is very reactive, but the potassium ion is stable. Briefly explain this difference in properties. 5. Element “X” reacts with sodium to form a compound with the formula Na2X. What group in the periodic table must “X” belong to? Explain. 15 COVALENT BONDING 1. Draw the structural diagram for each compound. (Note: the central atom is typically the first element listed in a compound, otherwise it is underscored). e. N2 i. F2 m. NF3 q. C2Br4 a. NCl3 j. SiBr4 n. CO f. CCl4 b. CO2 k. C2H4F2 o. O2 c. C2H4 g. OF2 l. HBr p. PCl3 d. HOBr h. SH2 VSEPR STRUCTURES & POLARITY 1. For each compound: i. Calculate the ΔEN ii. Draw the Structural diagram iii. Draw the 3D VSEPR shape iv. Is it polar or non-polar? a. SiCl4 b. PCl3 c. NF3 d. AlCl3 e. CaF2 f. H2Se g. SO3 h. CS2 i. * CH2Br2 j. * HCN * simplified rule does not apply!) 2. What two factors affect whether a molecule is going to be polar or non-polar overall? 16 CHEMICAL REACTIONS UNIT CHEMICAL NOMENCLATURE OF IONIC BINARY COMPOUNDS 1. Write the chemical formulas for the following: a. calcium iodide f. potassium bromide b. sodium fluoride g. zinc fluoride c. aluminum bromide h. barium bromide d. calcium hydride i. zinc hydride e. calcium oxide j. aluminum nitride 2. Name the following: a. AlF3 b. MgS c. CaF2 d. Na2S e. f. g. h. CaO Li2O KCl K2O i. j. k. l. k. l. m. n. o. silver sulphide barium oxide zinc sulphide magnesium chloride magnesium carbide m. n. o. p. MgCl2 BaI2 KI ZnH2 p. q. r. Ca3N2 AgBr SrO BeF2 lithium sulphide silver phosphide potassium oxide q. r. AlN Li4C CHEMICAL NOMENCLATURE OF MULTIVALENT COMPOUNDS 1. Write formulas for the following a. iron (II) oxide b. copper (I) sulphide c. tin (II) fluoride d. e. f. copper (II) oxide iron (II) nitride lead (IV) fluoride g. h. i. tin (IV) iodide iron (III) oxide lead (II) chloride 2. Write formulas for the following: a. iron (III) sulphide b. manganese (IV) oxide c. platinum (II) nitride d. mercury (I) sulphide e. antimony (V) oxide f. phosphorus (III) fluoride g. platinum (IV) sulphide h. i. j. k. l. m. n. cobalt (III) phosphide gold (III) oxide copper (I) sulphide cobalt (II) carbide gold (I) chloride lead (IV) sulphide tin (II) bromide o. p. q. r. s. t. iron (II) oxide nickel (III) sulphide phosphorus (III) oxide chromium (II) hydride chromium (II) phosphide bismuth (V) oxide 3. Name the following using IUPAC notation: f. CoS a. FeCl2 g. HgCl b. SnO2 c. PI3 h. AuI d. CuBr i. Sb2S5 j. As2O3 e. FeCl3 k. l. m. n. o. Hg2O Pb3N4 Sb2O3 CuF SnF2 p. q. r. s. t. PbO2 Cu2O AuN SbCl3 PbCl2 u. SnS2 CHEMICAL NOMENCLATURE OF SIMPLE POLYATOMIC COMPOUNDS 1. Write formulas for the following polyatomic salts: a. sodium chromate h. b. sodium acetate i. c. calcium sulphate j. d. potassium sulphate k. e. barium phosphate l. f. calcium dichromate m. g. lithium nitrate n. 2. Name the following polyatomic salts: a. Ba(BrO3)2 f. b. Ca(ClO3)2 g. c. BaSO4 h. d. Mg(BrO3)2 i. e. Ca3(PO4)2 j. copper (I) sulphate tin (II) carbonate mercury (II) hydroxide magnesium bromate ammonium carbonate silver nitrate lead (II) sulphate k. l. m. n. o. NaClO3 Al2(SO4)3 Na2SO4 PbSO4 Fe3(PO4)2 17 o. p. q. r. s. t. Zn(CH3COO)2 MgCrO4 Hg(ClO3)2 Ba3(PO4)2 Al(NO3)3 barium nitrate magnesium acetate silver carbonate aluminum cyanide iron (III) hydroxide copper (II) manganate p. q. r. Cu(NO3)2 Al2(Cr2O7)3 Fe(MnO3)3 CHEMICAL NOMENCLATURE OF MORE POLYATOMIC COMPOUNDS Write formulas for the following polyatomic compounds: 1. sodium phosphite 15. zinc carbonite 2. mercury (II) nitrite 16. magnesium percarbonate 3. iron (II) perchlorate 17. arsenic (V) nitrite 4. potassium perbromate 18. iron (II) hypochlorite 5. zinc sulphate 19. calcium hyposulphite 6. aluminum hypophosphite 20. potassium permanganate 7. copper (II) chlorite 21. antimony (III) chlorite 8. iron (III) hyponitrite 22. ammonium sulphite 9. calcium hypochlorite 23. silver bromite 10. tin (IV) chlorite 24. zinc chlorite 11. lead (II) perchlorate 25. tin (II) perchlorate 12. copper (II) hypobromite 26. gold (I) nitrite 13. antimony (V) sulphite 27. sodium thiosulphate 14. manganese (V) hypophosphite 28. copper (I) bicarbonate Name the following polyatomic compounds: 41. Hg(NO)2 51. Fe3(PO3)2 52. MgCrO4 42. AlPO3 53. NaHSO4 43. Ba(ClO2)2 54. Zn(ClO)2 44. FeSO3 55. SbPO3 45. Sn(SO4)2 56. Cu(ClO)2 46. As(NO3)3 57. KBrO4 47. Hg(ClO)2 58. (NH4)2SO4 48. LiNO2 59. K3PO2 49. CuSO4 60. NaClO4 50. (NH4)2CO4 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. As(NO4)5 Sb2(SO3)3 Zn3(PO2)2 Ag2S2O3 Mg(BrO4)2 CaHPO4 MnSO3 Pb(IO2)2 AsPO5 Cu(BrO4)2 Fe2(SO3)3 mercury (II) perchlorate manganese (II) sulphite zinc hydrogen phosphate potassium perbromate barium hypomanganite magnesium hypobromite lead (IV) phosphite mercury (II) perbromate calcium sulphite potassium perchlorate ammonium thiosulphate beryllium phosphate 72. 73. 74. 75. 76. 77. 78. 79. 80. CuHPO4 KClO4 (NH4)3PO3 AgNO2 Zn3(PO3)2 Fe(MnO4)2 LiNO SnS2O3 KHCO3 CHEMICAL NOMENCLATURE OF ACIDIC & BASIC COMPOUNDS 1. 2. Write formulas for the following compounds: a. perchloric acid b. hyponitrous acid c. iron (III) hydroxide d. bromic acid e. hydrophosphoric acid f. iodic acid g. sulphuric acid h. i. j. k. l. m. n. Name the following compounds: e. HNO2 (aq) a. HCl (aq) f. H2S (aq) b. HIO3 (aq) g. HBrO (aq) c. Cu(OH)2 (aq) h. H2CO3 (aq) d. H2SO3 (aq) carbonous acid hydroiodic acid magnesium hydroxide chromic acid sodium hydroxide chlorous acid lithium hydroxide i. j. k. l. Pb(OH)4(aq) H3PO2 (aq) HNO4 (aq) HClO3 (aq) o. p. q. r. s. t. m. n. o. p. pernitric acid manganous acid carbonic acid phosphorous acid hypobromous acid chloric acid HCH3COO (aq) H2SO5 (aq) HgOH (aq) HI (aq) q. r. HMnO3 (aq) Sb(OH)5 (aq) CHEMICAL NOMENCLATURE OF COVALENT BINARY COMPOUNDS 1. Write the chemical formulas for the following: a. hydrogen iodide b. nitrogen trifluoride c. carbon tetrabromide d. phosphorus pentahydride e. f. g. h. nitrogen dioxide carbon dioxide sulphur difluoride diphosphorus pentoxide 18 i. j. k. l. dihydrogen sulphide nitrogen trihydride oxygen dichloride carbon monoxide m. dihydrogen monoxide n. silicon dioxide 2. Name the following: a. SiF4 b. NCl3 c. H2S d. SCl4 o. p. e. f. g. h. NO CO2 N2O3 SCl2 dinitrogen trisulphide tetraboron tricarbide i. j. k. l. q. r. N2O5 NBr3 HBr PCl3 m. n. o. p. hydrogen peroxide carbon tetrahydride HI NH3 HBr H3P q. r. SF2 SiH4 CHEMICAL NOMENCLATURE REVIEW Write formulas for the following compounds: 1. sodium iodide 2. iron (III) oxide 3. sulphur dichloride 4. potassium hypophosphite 5. hydrophosphoric acid 6. lithium persulphate 7. ammonium nitrate 8. mercury (I) sulphate 9. tin (II) carbonite 10. antimony (V) hydroxide 11. dinitrogen oxide 12. ammonium carbonate 13. cobalt (II) nitrate 14. strontium persulphate 15. sodium peroxide 16. nickel (II) acetate 17. copper (II) sulphate pentahydrate 18. tin (II) hypocarbonite 19. hydrocyanic acid 20. iron (II) hydroxide 21. potassium permanganate 22. sodium acetate trihydrate 23. copper (II) sulphide 24. gold (I) fluoride 25. aluminum nitrite 26. lead (IV) acetate 27. sodium sulphate decahydrate 28. copper (I) hypophosphite 29. silver thiosulphate 30. carbonic acid 31. lithium perphosphate 32. ammonium hydroxide Name the following compounds: 50. NaBrO3 58. Sb2(SO4)3 59. H2S (aq) 51. Sb(ClO)5 60. HCH3COO (aq) 52. H2SO4 (aq) 61. Cl2O 53. Mg(OH)2 54. SO3 62. MgCr2O7 55. H2O2 63. Ba(NO3)2 56. LiCl 64. AlN 57. H3PO2 (aq) 65. P2O3 66. 67. 68. 69. 70. 71. 72. 73. GaH3 N2O5 H2S HNO2 (aq) HCl (aq) Pb(CO2)2 Sb2O3 Zn(IO3)2 74. 75. 76. 77. 78. 79. 80. 81. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. Fe(NO4)2 CuCO3 ICl LiClO CaHPO4 SO2 NH4OH BF3 phosphorus pentabromide barium hypocarbonite nitrous acid sulphur difluoride dinitrogen difluoride bismuth (III) iodate periodic acid magnesium oxide calcium bicarbonate phosphoric acid lithium peroxide dinitrogen tetroxide chromium (VI) chlorite silicon dioxide iron (III) iodide platinum (II) carbide beryllium fluoride 82. 83. 84. 85. 86. 87. 88. OCl2 SiO2 K2O2 Zn2C NaIO MgSO4 Pb(MnO3)4 BALANCING SKELETON EQUATIONS 1. Balancing chemical equations satisfies one of the most important chemical laws. What is the name of the law? 2. Balance the following skeleton equations: a. Mg + O2 MgO b. N2 + H2 NH3 c. P4 + O2 P2O3 d. HgO Hg + O2 e. Fe + H2O Fe2O3 + H2 f. CH4 + O2 CO2 + H2O g. Na + HCl NaCl + H2 h. Al2O3 Al + O2 i. Mg + N2 Mg3N2 j. C3H8 + O2 CO2 + H2O k. KClO3 KCl + O2 l. m. n. o. p. q. r. s. t. u. v. 19 MnO2 + HCl MnCl2 + Cl2 + H2O H3PO4 + NaOH Na3PO4 + H2O P4 + Cl2 PCl5 NO2 + H2O HNO3 + NO Na3PO4 + CaCl2 Ca3(PO4)2 + NaCl C6H14 + O2 CO2 + H2O Cu + HNO3 Cu(NO3)2 + NO2 + H2O NaHSO3 + H2SO4 Na2SO4 + SO2 + H2O C6H6 + O2 CO2 + H2O FeCl3 + Na2S Fe2S3 + NaCl NO + H2 N2 + H2O w. Fe2O3 + P4 Fe + P2O5 BALANCING WORD EQUATIONS Balance the following word equations: 1. zinc + hydrochloric acid zinc chloride + hydrogen 2. aluminum chloride + potassium potassium chloride + aluminum 3. sodium hydroxide + phosphoric acid sodium phosphate + water 4. iron (III) chloride + ammonium sulphide iron (III) sulphide + ammonium chloride 5. zinc sulphide + oxygen zinc oxide + sulphur dioxide 6. dicarbon dihydride (acetylene) + oxygen carbon dioxide + water 7. lead (II) nitrate lead (II) oxide + oxygen + nitrogen dioxide 8. nitric acid water + nitrogen dioxide + oxygen 9. manganese dioxide + hydrochloric acid manganese (II) chloride + water + chlorine 10. carbon + nitric acid nitrogen dioxide + water + carbon dioxide 11. tin + sulphuric acid tin (IV) sulphate + sulphur dioxide + water 12. sodium bromide + sulphuric acid sodium sulphate + sulphur dioxide + bromine + water 13. calcium + water calcium hydroxide + hydrogen 14. aluminum oxide + carbon + chlorine aluminum chloride + carbon monoxide 15. aluminum hydroxide + sulphuric acid aluminum sulphate + water IDENTIFYING TYPES OF REACTIONS For each of the following reactions, identify the type of reaction & balance the equation. 1. water hydrogen + oxygen 2. lithium + water lithium hydroxide + hydrogen 3. sulphuric acid + potassium hydroxide water + potassium sulphate 4. copper + silver nitrate silver + copper (II) nitrate 5. aluminum + oxygen aluminum oxide 6. methane (CH4) + oxygen carbon dioxide + water 7. hydrochloric acid + sodium hydroxide water + sodium chloride 8. sodium carbonate + copper (II) sulphate sodium sulphate + copper (II) carbonate 9. zinc + phosphoric acid zinc phosphate + hydrogen 10. water + carbon dioxide carbonic acid 11. calcium + oxygen calcium oxide 12. butane (C4H10) + oxygen carbon dioxide + water COMBUSTION, SYNTHESIS & DECOMPOSITION REACTIONS 1. Write out the balanced chemical equation for the following combustion reactions (include phase labels): a. C + O2 d. Zn + O2 g. C2H6 + O2 b. Mg + O2 e. Li + O2 h. C3H6 + O2 c. S8 + O2 f. CH4 + O2 i. C6H6O6 + O2 2. Write the reaction when each of the products from question 1 is placed in water. Is the solution acidic, basic or neutral? 3. Write out the balanced chemical equation for the following synthesis reactions (include phase labels): a. C + H2 c. N2 + H2 e. Li + N2 b. Mg + Br2 d. Zn + S8 f. H2 + P4 4. Write out the balanced chemical equation for the following decomposition reactions (include phase labels): a. NH3 b. N2H4 c. CO2 d. 20 H2O SINGLE DISPLACEMENT REACTIONS Refer to the metal & halogen activity series to determine the products (if any) for the following reactants. If a reaction does not occur, write NR. If a metal does react, assume the more stable ionic charge will form (refer to the periodic table). Take careful note of the states of each compound. 1. Li (s) + H2O (l) 8. Na (s) + H2O (l) 16. Pb (s) + H2O (l) 2. Al (s) + FeO (s) 9. Zn (s) + PbI4 (s) 17. Ni (s) + HCl (aq) 3. F2(g) + HCl(aq) 10. Pt (s) + H2SO4 (aq) 18. Al (s) + H3PO4 (aq) 11. Ni (s) + MgCO3 (s) 4. Cu (s) + H2O (l) 19. Ca (s) + H2O (l) 12. Ba (s) + H2O (l) 5. Mg (s) + CaCO3 (s) 20. Zn (s) + Pb(NO3)2 (aq) 13. Sn (s) + HgS (s) 6. Ag (s) + HCl (aq) 21. Ag (s) + CuSO4 (aq) 14. Al (s) + HNO3 (aq) 7. Fe (s) + HClO3 (aq) 15. Ca (s) + FeCl2 (aq) DOUBLE DISPLACEMENT REACTIONS Complete & balance the following equations. 1. NaCl (aq) + AgNO3 (aq) 5. 6. 2. MgCl2 (aq) + KOH (aq) 7. 3. BaCl2 (aq) + Na2SO4 (aq) 8. 4. Ca(OH)2 (aq) + HCl (aq) Identify the precipitate using subscripts (refer to a solubility table). NaOH (aq) + Fe(NO3)2 (aq) 9. CuCl2 (aq) + Na2S (aq) Na2CO3 (aq) + MgSO4 (aq) 10. Pb(NO3)2 (aq) + K2CO3 (aq) Pb(NO3)2 (aq) + H2S (aq) 11. CaCl2 (aq) + H2S (aq) Fe2(SO4)3 (aq) + NaOH (aq) 12. Al2(SO4)3 (aq) + NH4OH (aq) NET IONIC EQUATIONS 1. 2. For each of the following, Complete & balance the chemical equation Write the ionic & net ionic equation a. barium hydroxide & sodium sulphate b. ammonium carbonate & lead (II) nitrate c. silver nitrate & calcium chloride d. potassium hydroxide & zinc sulphate e. tin (II) acetate & barium hydroxide f. g. h. i. j. strontium nitrate & potassium sulphate aluminum metal & silver nitrate lead (II) nitrate & potassium chloride barium hydroxide & sulphuric acid chlorine gas & sodium iodide What is the net ionic equation for any acid-base neutralization reaction? QUANTITIES IN CHEMICAL REACTIONS UNIT MOLAR MASS PROBLEMS 1. What does it mean for carbon to have a molar mass of 12.01 g/mol? 2. Find the molar masses of each of the following: a. water (18.02 g/mol) b. carbon dioxide (44.01 g/mol) c. sodium bicarbonate (84.01 g/mol) d. lithium hydroxide (23.95 g/mol) e. f. g. 21 calcium perphosphate silver nitrate zinc chloride (342.18 g/mol) (169.88 g/mol) (136.29 g/mol) AVOGADRO’S NUMBER PROBLEMS 1. How many objects are present in one mole? 2. How many atoms can be found in: a. 3.00 mol of lead (1.81 x 1024) b. 6.13 mol of silver (3.69 x 1024) c. d. 0.00685 mol of argon 0.0320 mol of sodium 3. How many molecules can be found in: a. 0.0700 mol of carbon dioxide (4.21 x 1022) b. 13.2 mol of ammonia (7.95 x 1024) c. d. 4.56 mol of oxygen gas (2.75 x 1024) 31.1 mol of sodium chloride (1.87 x 1025) 4. How many moles are represented by: a. 7.5 x 1023 atoms of gold (1.2) b. 8.24 x 1025 atoms of potassium (137) c. d. 1.45 x 1022 molecules of sucrose (0.0241) 1.73 x 1025 molecules of water (28.7) 5. Sodium bromide, NaBr, dissociates into sodium ions & bromide ions. If 0.0125 mol of sodium bromide dissociated: a. How many sodium ions were formed? (7.53 x 1021) b. How many bromide ions were formed? (7.53 x 1021) c. How many ions in total resulted from the dissociation? (1.51 x 1022) 6. Magnesium iodide, MgI2, dissociates into one magnesium ion for every two iodide ions. If 0.0350 mol of magnesium iodide dissociated: a. How many magnesium ions were formed? (2.11 x 1022) b. How many iodide ions were formed? (4.21 x 1022) c. How many ions in total resulted from the dissociation? (6.32 x 1022) 7. One molecule of methane consists of one carbon atom & four hydrogen atoms. How many atoms in total are in 0.00725 mol of methane? (2.18 x 1022) (4.12 x 1021) (1.93 x 1022) MOLE RELATED PROBLEMS (# OF PARTICLES) 1. How many molecules are there in 1.25 mol of sulphuric acid? (7.53 x 1023 molecules) 2. How many helium atoms are there in 2.64 mol of helium gas? (1.59 x 1024 atoms) 3. How many moles of oxygen molecules are in 1.23 x 1024 diphosphorus pentoxide molecules? (5.11 moles) 4. How many moles of magnesium hydroxide can be created using 2.23 x 1024 oxygen atoms? (1.85 moles) 5. How many carbon atoms are in 1.25 mol of silver acetate? (1.51 x 1024 atoms) MOLE RELATED PROBLEMS (# OF MOLES) 1. Which has a greater mass, one mole of lead atoms or ten moles of water molecules? (Pb) 2. What is the mass of 1.31 mol of silver nitrate? (223 g) 3. What is the mass of 2.44 mol of hydrogen peroxide? (83.0 g) 4. How many moles of molecules are in 53 g of sodium carbonate? (0.50 mol) 5. An unknown element is studied. If 8.65 mol of the element has a mass of 211 g, what is the element? (24.4 g/mol) 6. A binary compound is studied. It is found that 1.75 mol of the compound has a mass of 29.8 g. If the compound contains one nitrogen atom, what is the compound? (17.0 g/mol) 7. What mass of carbon are in 1.25 mol of silver acetate? (30.0 g) 8. What mass of chlorine gas is in 5.34 mol of iron (III) chloride? (568 g) 22 MOLE RELATED PROBLEMS (ADVANCED CALCULATIONS) 1. How many molecules are in 11.3 g of glucose, C6H12O6? (3.78 x 1022 molecules) 2. How many molecules are in 12.5 g of aluminum chloride? (5.64 x 1022 molecules) 3. How many atoms of carbon are in 17.1 g of sucrose, C12H22O11? (3.61 x 1023 atoms) 4. How many fluorine atoms can be made from 21.3 g of boron trifluoride? (5.67 x 1023 atoms) 5. How many molecules of oxygen can be made from 9.52 g of nickel (III) oxide? (5.20 x 1022 molecules) 6. What mass of carbon tetrahydride can be made from 2.66 x 1025 molecules of carbon tetrahydride? (709 g) 7. What mass of nitric acid can be made from 1.23 x 1024 oxygen atoms? (42.9 g) 8. What mass of oxygen gas can be made from a total of 5.84 x 1024 oxygen atoms? (155 g) % COMPOSITION PROBLEMS (FROM CHEMICAL FORMULAS) 1. Find the percentage composition of the indicated element in each of the following compounds: a. Na in NaCl (39.34%) b. H in HBr (1.248%) c. O in SO2 (49.95%) d. N in NH3 (82.22%) e. O in Ca(NO3)2 (58.50%) f. P in zinc phosphate (16.04%) g. Na in sodium oxide (74.19%) 2. Determine the % composition of oxygen & water present in Epsom salts, MgSO4 · 7 H2O. 3. An ore of aluminum called bauxite has the formula Al2O3 · 2 H2O. What mass (in kg) of bauxite would be needed for the extraction of one kilogram of aluminum? (2.56 kg) 4. The bones of an average adult person has a mass of approximately 11 kg & contains approximately 48% calcium phosphate. Calculate the mass (in kg) of phosphorus present in the skeleton of an average adult. (1.1 kg) (%O = 71.39%) % COMPOSITION PROBLEMS (FROM EXPERIMENT) 1. Students heated a sample of copper in excess oxygen & made the following observations: Mass of crucible & lid 20.10 g Mass of crucible, lid & sample 21.04 g Mass of crucible, lid & product 21.20 g Calculate the % composition (by weight) of copper oxide from this information. (%Cu = 85.45%) 2. 10.0 g of Ca was placed in a large crucible & heated. The empty crucible weighed 186 g. After the Ca was heated, the crucible & contents weighed 2.00 x 102 g. Calculate the % composition of CaO. (%Ca = 71.4%) 3. An oxide of mercury decomposes (into its constituent elements) when heated above 500°C. A 50.0 g sample of the oxide was heated & 46.3 g of mercury was obtained. Calculate the % composition of the mercury oxide. (%Hg = 92.6%) 4. A student decomposes a sample of potassium bromide of mass 7.14 g. She finds that there are 2.35 g of potassium & the rest is bromine. Use this information to calculate the % composition of potassium bromide. (%K = 32.9%) 5. A certain compound is known to be 32.8% lead. If 151 g of this compound are decomposed, what mass of lead will be recovered? (49.5 g) 6. A compound is known to be 25.6% arsenic. If 23.8 g of arsenic is recovered, what was the mass of the original sample? (93.0 g) 23 SIMPLEST FORMULA PROBLEMS 1. Determine the empirical formula of a compound made up of 31.14% sulphur & 68.86% chlorine. (SCl2) 2. What is the empirical formula of a compound that is 15.9% boron & 84.1% fluorine? 3. An inorganic salt is composed of 17.6% sodium 39.7% chromium & the remainder oxygen. What is the empirical formula of this salt? (Na2Cr2O7) 4. Compound X contains 69.90% carbon, 6.85% hydrogen & the remainder oxygen. Determine the empirical formula of compound X. (C12H14O3) 5. A chemical compound is made up of 13.26 g chromium, 12.26 g sulphur & 24.48 g oxygen. What is the simplest formula of the compound? (Cr2(SO4)3) 6. A 50.5 g sample of mercury oxide was heated & 48.6 g of mercury was obtained. Find the simplest formula of the mercury oxide. (Hg2O) 7. Students heated a sample of iron in excess oxygen & made the following observations: Mass of crucible & lid 19.76 g Mass of crucible, lid & iron 22.05 g Mass of crucible, lid & iron oxide 22.71 g Find the simplest formula of iron oxide from this information. (BF3) (FeO) MOLECULAR FORMULA PROBLEMS 1. The simplest/empirical formula of butane, the fuel used in disposable lighters, is C2H5. In an experiment, the molar mass of butane was determined to be 58 g/mol. What is the molecular formula of butane? (C4H10) 2. A compound has the simplest/empirical formula CHO. Its molecular mass is 116 g/mol. What is its molecular formula? (C4H4O4) 3. A compound having a molecular mass of 90.0 g/mol is composed of 39.95% carbon, 6.69% hydrogen & the remainder is oxygen. Calculate the molecular formula of this compound. (C3H6O3) 4. A compound contains only carbon & hydrogen. It contains 80.0% carbon. It is also known that 1.45 mol of this gas has a mass of 43.5 g. Calculate the molecular formula of this gas. (C2H6) 5. Ether contains 64.86% carbon, 13.62% hydrogen & 21.52% oxygen. In addition it is known that 1.25 x 10 -2 mol of this gas has a mass of 0.926 g. Calculate the molecular formula of this gas. (C4H10O) 6. A compound has a molar mass of 170.2 g/mol. Its percentage composition is 49.38% carbon, 3.55% hydrogen, 9.40% oxygen & the remainder is sulphur. Calculate the molecular formula. (C7H6OS2) HYDRATE PROBLEMS 1. A 2.78 g sample of hydrated FeSO4 was heated to remove all the water of hydration. The mass of the anhydrous FeSO4 was 1.52 g. Calculate the number of water molecules associated with each formula unit of FeSO4. (7) 2. A 19.76 g sample of hydrated sodium acetate was heated & 11.91 g of anhydrous salt remained. Calculate the number of water molecules associated with each formula unit of sodium acetate. (3) 3. Copper (II) sulphate pentahydrate is a well-known hydrate. If a sample of the hydrate was heated & 7.24 g of anhydrous copper (II) sulphate was recovered, what was the mass of the original hydrated sample? (11.3 g) 4. A 5.00 g sample of borax, Na2B4O7 · 10 H2O, was thoroughly heated to remove all the water of hydration. What mass of anhydrous compound remained? (2.64 grams) 5. (Tricky) A sample of cobalt (II) nitrate hydrate was heated to remove all the water of hydration. The hydrate was found to be 65.96% oxygen. Calculate the number of water molecules associated with each formula unit of cobalt (II) nitrate. (6) 24 6. (Tricky) Epsom salts is MgSO4 x H2O. The hydrate was found to contain 71.4% oxygen. Calculate the number of water molecules associated with each formula unit of magnesium sulphate hydrate. (7) 7. (Tricky) Zinc nitrate hydrate, Zn(NO3)2 x H2O, contains 21.98% zinc by mass. What is the value of x? (6) SIMPLE STOICHIOMETRY PROBLEMS (MOL-MOL) 1. Butane burns with the oxygen in air to give carbon dioxide & water. How many moles of carbon dioxide would be produced from 0.150 mol of butane? (0.600 mol) _____ C4H10 (g) + _____ O2 (g) _____ CO2 (g) + _____ H2O (g) 2. Ethanol burns with the oxygen in air to give carbon dioxide & water. How many moles of water would be produced from 0.250 mol of ethanol? (0.750 mol) _____ C2H5OH (l) + _____ O2 (g) _____ CO2 (g) + _____ H2O (l) 3. Nickel (II) chloride reacts with sodium phosphate to precipitate nickel (II) phosphate. How many moles of nickel (II) chloride are needed to produce 0.479 mol of nickel (II) phosphate? (1.437 mol) _____ NiCl2 (aq) + _____ Na3PO4 (aq) _____ Ni3(PO4)2 (s) + _____ NaCl (aq) 4. Nitric acid, HNO3, is manufactured by the Ostwald process, in which nitrogen dioxide, NO2, reacts with water. How many moles of nitrogen dioxide are required in this reaction to produce 0.750 mol of HNO3? (1.13 mol) _____ NO2 (g) + _____ H2O (l) _____ HNO3 (aq) + _____ NO (g) 5. White phosphorus, P4, is prepared by fusing calcium phosphate, Ca3(PO4)2, with carbon, C, & sand, SiO2, in an electric furnace. How many moles of Ca3(PO4)2 are required to give 1.35 mol of phosphorus? (2.70 mol) _____ Ca3(PO4)2 (s) + _____ SiO2 (s) + _____ C (s) _____ P4 (g) + _____ CaSiO3 (l) + _____ CO (g) EXCESS REAGENT/REACTANT MASS-MASS STOICHIOMETRY PROBLEMS 1. What two things you must have in order to solve any stoichiometry problem? 2. What is an excess reagent? 3. Calcium reacts with water to produce calcium hydroxide & hydrogen. What mass of hydrogen is produced by the reaction of 12.4 g of calcium with excess water? (0.625 g) 4. Manganese (IV) oxide reacts with hydrochloric acid to produce manganese (II) chloride, water & chlorine. If 48.8 g of manganese (IV) oxide was used, what mass of water would be produced? (20.2 g) 5. Iron (II) oxide reacts with sulphur, S8, to produce iron metal & sulphur dioxide. If 193 g of iron (II) oxide was used, what mass of sulphur dioxide will be produced? (86.1 g) 6. Sodium peroxide reacts with water to produce sodium hydroxide & oxygen. What mass of oxygen can be prepared by reacting 18.0 g of sodium peroxide with water? (3.69 g) 7. What mass of mercury (II) oxide must be decomposed to produce 2.56 x 1023 molecules of oxygen? (184 g) 8. What mass of methane, CH4, must be burned to produce 12.3 g of water? 9. Sodium oxide & water produce sodium hydroxide in a synthesis reaction. A student had 31.2 g of sodium oxide. What mass of water should be reacted with this so that no water & no sodium oxide will be left over? (9.07 g) (5.48 g) 10. Titanium metal is made by reacting titanium (IV) chloride with magnesium metal. Magnesium chloride is also produced. How many kilograms of magnesium are required to produce 1.00 kg of titanium? (1.02 kg) 25 LIMITING REAGENT/REACTANT STOICHIOMETRY PROBLEMS 1. Hydrazine, N2H4, is used as a rocket fuel. It reacts with oxygen to form nitrogen gas & water. In a particular rocket engine, 2.29 kg of hydrazine & 3.14 kg of oxygen are available for reaction. Calculate the mass of water produced. (2.57 kg) 2. Sodium & chlorine react to form sodium chloride. If 12.5 g of sodium & 25.5 g of chlorine gas are available for reaction, determine the mass of NaCl produced. (31.8 g) 3. One type of stomach antacid consists of magnesium hydroxide. This reacts with stomach acid, which is mainly hydrochloric acid, to form magnesium chloride & water. If 2.86 g of magnesium hydroxide & 5.15 g of hydrochloric acid are available for reaction, what mass of magnesium chloride is produced? (4.67 g) 4. Hydrogen gas reacts with nitrogen gas to form ammonia. What mass of ammonia could be produced if 25.0 g of hydrogen gas is mixed with 95.0 g of nitrogen? (116 g) 5. Aluminum reacts with iron (III) oxide in a single displacement reaction. If 46.6 g of aluminum are mixed with 145 g of iron (III) oxide, what mass of iron would result? (96.5 g) 6. Ammonia reacts with oxygen to form nitrogen monoxide, NO, & water. What mass of nitric oxide could be produced if 68.0 g of ammonia is mixed with 35.0 g of oxygen? (26.3 g) 7. Calcium hydroxide & carbon dioxide react to form calcium carbonate & water. If 11.20 g of calcium hydroxide is reacted with 16.65 g of carbon dioxide, what mass of calcium carbonate will form? (15.20 g) 8. Bismuth (III) oxide reacts with carbon to form bismuth & carbon dioxide. A student mixed 23.3 g of bismuth (III) oxide with 0.900 g of carbon. What is the mass of carbon dioxide produced? (3.30 g) 9. Ethane, C2H6, burns in oxygen to form carbon dioxide & water. If 0.0170 g of ethane is mixed with 0.0672 g of oxygen, what is the combined mass of the two products? (0.0803 g) 10. AsCl3 reacts with H2S to form As2S3 & HCl. If 4.58 g of AsCl3 are mixed with 1.36 g of H2S, how much of which reactant will be left over after the reaction? (0.0680 g) STOICHIOMETRY REVIEW PROBLEMS 1. Tungsten metal, W, is used to make incandescent bulb filaments. The metal is produced by a reaction between WO3 & H2. Water is the other product. What mass of tungsten metal can be obtained from 4.81 kg of WO3? (3.81 kg) 2. CCl4 is a strong organic solvent. It is produced when carbon disulphide reacts with chlorine gas to produce CCl4 & S2Cl2. What mass of carbon tetrachloride would be produced by the reaction of 62.7 g of Cl2? (45.3 g) 3. Dinitrogen pentoxide decomposes to form nitrogen dioxide & oxygen gas. If 1.62 g of oxygen gas are produced, how many grams of nitrogen dioxide would also be produced? (9.32 g) 4. Ammonia & hydrogen chloride react to form ammonium chloride. If 1.00 g of ammonia & 1.00 g of hydrogen chloride react, identify the limiting reagent & calculate the mass of ammonium chloride that will be formed. (1.47 g) 5. Commercial bleach is sodium hypochlorite. It is prepared when chlorine gas reacts with sodium hydroxide to produce sodium chloride, sodium hypochlorite & water. If 4.5 g of chlorine gas is mixed with 5.6 g of sodium hydroxide, what mass of sodium hypochlorite will be produced? (4.7 g) 6. MnO2 reacts with HCl to produce MnCl2, water & Cl2. If 24.0 g of MnO2 react with 38.2 g of HCl, calculate the mass of excess reagent remaining after the reaction. (1.23 g) 7. Ammonia & oxygen gas react to form nitrogen monoxide & water. A chemist places 1.22 kg of ammonia & 1.96 kg of oxygen gas into a reacting vessel. Identify the limiting reagent & calculate the mass of water produced. (1.32 kg) 8. A student reacts 14.0 g of chlorine gas with 8.30 g of water to produce hydrogen chloride & oxygen gas. Identify the limiting reagent & calculate the total mass of products produced. (17.6 g) 26 % YIELD PROBLEMS 1. The following reaction proceeds with a 70.0% yield: C6H6 + HNO3 C6H5NO2 + H2O Calculate the mass of C6H5NO2 expected if 12.8 g of C6H6 reacts with excess HNO3. (14.1 g) 2. Sulphur trioxide & water react to form sulphuric acid. If 65.7 g of sulphur trioxide react, what is the theoretical yield of the sulphuric acid? If the % yield is 85.0%, what was the actual yield of sulphuric acid? (68.4 g) 3. Nitric acid is one of the components of acid rain. It is produced when nitrogen dioxide reacts with water to form nitric acid & nitrogen monoxide. If 80.0 g of nitrogen dioxide react, what is the theoretical yield of nitric acid? If 65.0 g are produced, what is the % yield? (89.0%) 4. Yeasts can act on a sugar, such as glucose, in the following reaction: C6H12O6 2 C2H5OH + 2 CO2 If 223 g of C2H5OH are recovered after 1.63 kg of glucose react, what is the percentage yield of the reaction? (26.7%) 5. Mercury, in its elemental form or in a chemical compound is highly toxic. Water-soluble mercury compounds, such as Hg(NO3)2, can be removed from industrial wastewater by adding Na2S to the water, which forms a precipitate of HgS, which can then be filtered out. If 3.45 x 1023 molecules of Hg(NO3)2 are reacted with excess Na2S, what mass of HgS can be expected if this process occurs with 97.0% yield? (129 g) Hg(NO3)2 (aq) + Na2S (aq) HgS (s) + 2 NaNO3 (aq) % PURITY PROBLEMS 1. Sodium carbonate is synthesized as follows: CaCO3 (s) + 2 NaCl (aq) Na2CO3 (s) + CaCl2 (aq) What mass of Na2CO3 can be produced from 3.40 kg of 87.1% pure CaCO3 & an unlimited amount of NaCl? (3.14 kg) 2. AgNO3 reacts with copper metal in a single displacement reaction to produce silver metal & copper (II) nitrate. If 45.0 g of 81.0% pure copper react, what mass of silver should be produced? (124 g) 3. Pure iron can be produced by the following reaction: Fe3O4 (s) + 4 H2 (g) 3 Fe (s) + 4 H2O What mass of iron can be produced if you have 1.70 kg of 35.0% pure Fe3O4 & unlimited hydrogen? (431 g) 4. Given the following reaction: 4 FeS2 + 11 O2 2 Fe2O3 + 8 SO2 What mass of 73.5% pure oxygen gas is needed to produce 16.0 g of iron (III) oxide? 5. Chlorine gas can be produced by the following reaction: MnO2 (s) + 4 HCl (aq) MnCl2 (aq) + Cl2 (g) + 2 H2O (l) What mass of 63.0% pure HCl would you need to prepare 8.00 kg of chlorine gas? (26.1 kg) 6. Copper metal is produced by the following reaction: 2 Cu2O (s) + Cu2S (s) 6 Cu (s) + SO2 (g) If 2.50 kg of 35.0% pure copper (I) oxide is heated with 1.40 kg of 20.0% pure copper (I) sulphide, find the mass of copper metal produced. (671 g) 27 (24.0 g) SOLUTIONS & SOLUBILITY UNIT DETERMINING SOLUBILITY 1. What does it mean for a substance to be soluble? 2. Describe what happens during: a. ionic dissociation b. covalent ionization 3. For each of the following compounds, determine if the compound will dissolve (if at all) when added to water? State the reason why. a. K2O g. NaBr j. HF d. MgCl2 h. BaSO4 k. BF3 b. NCl3 e. HNO3 i. Na2SO4 c. CH3OH f. CH4 4. Why is dissolving normally considered to be a physical change? 5. Given any chemical compound, outline the steps necessary to determine if a compound is soluble or insoluble in water. c. simple dissolving CONCENTRATION UNIT CONVERSIONS 1. What are the six concentration units? Where might each concentration unit be useful? (In other words, under which context would the use of each concentration unit make more sense?) 2. Perform the indicated conversions (assume the solvent is water where d(water) = 1.0 g/mL): a. 12.5 ppm to ppb b. 5.0 m/v% NaOH to mol/L c. 2.30 mol/L NaCH3COO to m/v% d. 0.00333 m/v% to ppm e. 1.51 m/v% HCl to v/v%; d(HCl) = 1.19 g/mL f. 0.750 m/m% CH3OH to mol/L; d(solution) = 0.800 g/mL g. 536 ppm AgNO3 to mol/L (1.25 x 104 ppb) (1.25 mol/L) (18.9 m/v%) (33.3 ppm) (1.27 v/v%) (0.187 mol/L) (0.00316 mol/L) 3. The concentration of chlorine, Cl2, in a swimming pool is generally kept in the range of 1.4 to 4.0 mg/L. The water in a certain pool has 3.0 mg/L of chlorine. Express this value as ppm & ppb. (3.0 ppm , 3.0 x 103 ppb) 4. Some municipalities add sodium fluoride to drinking water to help protect the teeth of children. The concentration of sodium fluoride, NaF, is maintained at 1.2 x 10-3 g/L. Express this concentration in m/v %. (1.2 x 10-4) CONCENTRATION FORMULA PROBLEMS 1. A solution of hydrochloric acid, HCl, was formed by dissolving 1.52 g of hydrogen chloride gas in enough water to make 24.1 mL of solution. What is the m/v% concentration of the solution? (6.31%) 2. Milk fat is present in milk. Whole milk usually contains about 5.000% milk fat (v/v). If you drink a glass of milk with a volume of 250.0 mL, what volume of milk fat have you consumed? (12.50 mL) 3. If 55.00 g of KOH, is dissolved in 100.0 g of water, what is the m/m% concentration of the solution? (35.48%) 4. Steel is an alloy of iron & carbon. The % composition of carbon in steel is about 1.7% (m/m). It also contains small amounts of other materials, such as manganese & phosphorus. What mass of carbon is needed to make a 5.0 kg sample of steel? (85 g) 5. At 25.0°C, a saturated solution of carbon dioxide gas has a concentration of 0.145% (m/v). What mass of carbon dioxide is present in 250.0 mL of the solution? (0.363 g) 6. Calculate the m/m % of each of the following solutions: a. 8.60 g of sodium chloride, NaCl, dissolved in 95.0 g of water. b. 375 mg of calcium chloride, CaCl2, in 50.0 g of solution. 28 (8.30%) (0.750%) c. 225 mg of sulphuric acid, H2SO4, in 20.0 g of solution. (1.13%) 7. A 25.0 g sample of 14 karat gold contains 10.4 g of copper metal. What is the m/m % of copper in 14 karat gold? (41.6%) 8. A solution of potassium iodide, KI, has a concentration of 2.50% (m/m). If this solution contains 258 mg of potassium iodide, what is the mass of the solution? (10.3 g) 9. Coffee beans contain 1.45% caffeine (m/m). What mass of caffeine is present in 125 g of coffee beans? (1.81 g) 10. Water is added to 21.0 mL of ethanol, CH3CH2OH, until the total volume of the mixture is 100.0 mL. Calculate the v/v % of the alcohol present in the mixture. (21.0%) MOLAR CONCENTRATION PROBLEMS 1. A student mixed 4.25 mol of magnesium sulphide, MgS, in water to a final volume of 6.00 L. What is the molar concentration of the solution? (0.708 mol/L) 2. A solution was made by mixing 76.3 g of calcium nitrate, Ca(NO3)2, in water to a total volume of 4.25 L. What was the molar concentration? (0.109 mol/L) 3. A student needs to make 2.50 L of a solution with a molar concentration of 0.275 mol/L. How many moles of solute should be used? (0.688 mol) 4. A student was asked to mix 350.0 mL of a 0.150 mol/L solution of sodium carbonate, Na2CO3. What mass of sodium carbonate is required? (5.56 g) 5. Suppose 2.50 L of 0.125 mol/L sodium hydroxide, NaOH, solution is needed for a lab. However, only 0.500 mol/L sodium hydroxide is available. What volume of concentrated sodium hydroxide is needed? (625 mL) 6. What concentration of solution is obtained by diluting 50.0 mL of 0.720 mol/L aqueous NaNO3, to 0.400 L? (0.0900 mol/L) 7. A solution is prepared by adding 600 mL of distilled water to 100.0 mL of 0.150 mol/L ammonium nitrate, NH4NO3. Calculate the molar concentration of the solution. (0.0214 mol/L) 8. Sulphuric acid, H2SO4, can be sold as a 18.0 mol/L solution. What volume of water is needed to dilute 10.0 mL of the sulphuric acid to obtain a concentration of 1.50 mol/L? (1.10 102 mL) 9. Water is used to dilute 8.00 mol/L potassium nitrate, KNO3, solution to produce 700.0 mL of a solution with a concentration of 6.00 mol/L. What volumes of water & potassium nitrate solution are used? (525 mL, 175 mL) 10. Concentrated hydrochloric acid, HCl, has a density of 1.19 g/mL & a percentage purity of 39.1%. Suppose a lab required 7.25 L of 0.500 mol/L solution. What volume of concentrated hydrochloric acid (in mL) is needed for the dilution? (284 mL) DILUTION PROBLEMS 1. A student mixed 24.5 mL of a stock solution of potassium permanganate, KMnO4, with a concentration of 5.25 mol/L with enough water to make 750 mL of a new solution. a. What was the final concentration? (0.172 mol/L) b. How much additional water is necessary to create a solution of concentration 0.125 mol/L? (279 mL) 2. A solution was made by mixing 275 mL of a stock solution of sodium nitrate, NaNO3, with a concentration of 6.25 mol/L, into water. The final concentration was 1.20 mol/L. What was the final volume of the solution? (1.43 L) 3. A lab required 250.0 mL of LiOH solution with a concentration of 0.125 mol/L. If the stock solution was 5.50 mol/L, how much of the stock solution was required to make the dilute solution? (5.68 mL) 4. A solution was made by mixing 325 mL of stock solution, with a concentration of 2.50 mol/L, with 525 mL of water. a. What was the final concentration? (0.956 mol/L) b. How much additional water is necessary to create a solution of concentration 0.305 mol/L? (1.81 L) 5. A solution was made by mixing 175 mL of stock solution with water. The new solution had a volume of 1.50 L & a concentration of 0.250 mol/L. What was the concentration of the stock solution? (2.14 mol/L) 29 6. A stock solution was made by mixing 37.5 g of calcium nitrate, Ca(NO3)2, in water to a final volume of 250.0 mL. Afterwards, 35.0 mL of the stock solution were mixed in water to a final volume of 500 mL. a. What was the concentration of stock solution? (0.914 mol/L) b. What was the concentration of the new solution? (0.0640 mol/L) 7. A stock solution was made by mixing 78.4 g of (NH4)2CO3, in water to a final volume of 425 mL. Then some of the stock solution was used to make another solution with a volume of 75.0 mL & a concentration of 1.25 mol/L. a. What was the concentration of the stock solution? (1.92 mol/L) b. What volume of the stock solution was used to make the final solution? (48.8 mL) 8. A student made 500.0 mL of a stock solution of potassium phosphate, K3PO4. Then she mixed 35.25 mL of the stock solution with water to make a new solution with a volume of 125.0 mL & a concentration of 0.1250 mol/L. What mass of potassium phosphate did the student use to make the stock solution? (47.06 g) SOLUTIONS & SOLUBILITY PROBLEMS For each of the following compounds, use the solubility table to predict if it will form a solution. If yes, calculate the molar concentration. 1. 50.0 g of sodium phosphate, Na3PO4, in 500 mL of solution. 2. 75.0 g of magnesium carbonate, MgCO3, 300 mL of solution. 3. 85.5 g of aluminum chloride, AlCl3, in 450 mL of solution. 4. 102.5 g of barium hydroxide, Ba(OH)2, in 600.0 mL of solution. 5. 86.5 g of calcium hydroxide, Ca(OH)2, in 350 mL of solution. 6. 95.2 g of aluminum phosphate, AlPO4, in 425 mL of solution. 7. 35.5 g of magnesium bromide, MgBr2, in 275 mL of solution. 8. 57.3 g of lead (II) chloride, PbCl2, in 175 mL of solution. 9. 48.0 g of barium chloride, BaCl2, in 215 mL of solution. 10. 27.5 g of ammonium carbonate, (NH4)2CO3, in 55.0 mL of solution. Answers: 1. 0.610 mol/L 3. 1.43 mol/L 4. 0.9970 mol/L 7. 0.701 mol/L 9. 1.07 mol/L 10. 5.20 mol/L Take the compounds that will form solutions & pair them up in order. For each pair: write & balance an equation to show the reaction between the two. identify which product is the precipitate, using phase labels. write an ionic equation. write a net ionic equation. SOLUBILITY PROBLEMS 1. In general, as temperature increases, what happens to the solubility of each substance in water? (assuming it is soluble) a. solid b. liquid c. gas 2. Calculate the solubility, in grams per 100 mL of water, of potassium sulphate if 1.20 g of the solid dissolves in 10.5 mL of water at 20°C. (11.4 g/100 mL) 3. The solubility of aluminum fluoride is 0.559 g/100 mL water at 25°C. Is it possible to dissolve 3.0 g of solid in 500 mL of water at 25°C? Show your calculations. (2.80 g) 4. Molar solubility refers to the solubility of a substance in mol/L. The solubility of potassium bromide at 50°C is 80 g/100 mL. Convert this value to molar solubility. (6.72 mol/L) 30 5. A glass of cold water left sitting on a counter at room temperature usually develops many small bubbles on the inside of the glass. Describe what is likely happening. 6. The solubility of AlF3 is listed as 2.0 g/100 mL at a certain temperature. List two ways to dissolve 3.0 g of AlF3. 7. Potassium alum, KAl(SO4)2 · 12 H2O, is used to stop bleeding from small cuts. The solubility of potassium alum, at various temperatures, is given in the following table: Solubility (g/100 g of water) Temperature (°C) 4 0 10 10 15 20 23 30 31 40 49 50 67 60 101 70 135 80 a. Plot a graph of solubility against temperature. b. From your graph, interpolate the solubility of potassium alum at 67°C. c. By extrapolation, estimate the solubility of potassium alum at 82°C. d. Look at your graph. At what temperature will 120 g of potassium form a saturated solution in 100 g of water? e. Look at your graph. How much of 35 g of potassium alum will not dissolve at 35°C? SOLUTION STOICHIOMETRY PROBLEMS 1. A student mixed 35.0 mL of a 0.525 mol/L solution of potassium iodide with excess lead (II) nitrate in a double displacement reaction. What mass of lead (II) iodide was produced in the reaction? (4.24 g) 2. In a single displacement reaction, a copper wire was placed in 125 mL of a solution of silver nitrate with a concentration of 0.100 mol/L, & the reaction proceeded until all the silver nitrate reacted. Suppose 1.05 g of silver metal was recovered in an experiment. What was the % yield of the reaction? (77.9%) 3. Excess CuSO4 reacted with 32.5 mL of sodium carbonate solution in a double displacement reaction. If 0.750 g of copper (II) carbonate were produced, what was the concentration of the sodium carbonate solution? (0.187 mol/L) 4. Copper metal reacts with nitric acid. If 275 mL of nitric acid with a concentration of 6.00 mol/L react, what mass of copper would be required to react with it? The unbalanced chemical equation is below. (39.3 g) Cu (s) + HNO3 (aq) Cu(NO3)2 (aq) + NO (g) + H2O (l) 5. Nickel (II) chloride reacts with sodium phosphate in a double displacement reaction. If 1.37 g of nickel (II) phosphate is produced, what volume of 0.125 mol/L nickel (II) chloride is needed for the reaction? (89.8 mL) 6. The concentration of magnesium ions (assume magnesium chloride, MgCl2) in seawater was analyzed & found to be 0.0500 mol/L. What minimum volume of 0.200 mol/L sodium hydroxide, NaOH, would be needed in an industrial process to precipitate all of the magnesium ions, Mg2+, from 1000 L of sea water? (5.00 x 102 L) 7. Aqueous solutions that contain silver ions are usually treated with chloride ions to recover silver chloride, AgCl. What is the minimum volume of 0.25 mol/L magnesium chloride, MgCl2, needed to precipitate all the silver ions in 60.0 mL of 0.30 mol/L silver nitrate, AgNO3? (36 mL) 8. Ammonium phosphate, (NH4)3PO4, can be used as a fertilizer. 6.00 g of (NH4)3PO4 is dissolved in sufficient water to produce 300 mL of solution. What are the concentrations of NH4+ & PO43- present? (0.402 mol/L & 0.134 mol/L) 9. 8.76 g of sodium sulphide, Na2S, is added to 350 mL of 0.250 mol/L lead (II) nitrate solution, Pb(NO 3)2. Calculate the maximum mass of precipitate that can form. (20.9 g) 10. Silver chromate, Ag2CrO4, is insoluble. It forms a brick-red precipitate. Calculate the mass of silver chromate that forms when 50.0 mL of 0.100 mol/L silver nitrate, AgNO3, reacts with 25.0 mL of 0.150 mol/L sodium chromate. (0.829 g) 11. Suppose that you want to remove the barium ions from 120 mL of 0.0500 mol/L barium nitrate solution, Ba(NO3)2. What is the minimum mass of sodium carbonate, Na2CO3, that you should add? (0.636 g) 31 CONJUGATE ACIDS & BASES 1. What is the Arrhenius definition of acids & bases? 2. What is the Bronsted-Lowry definition of acids & bases? 3. For each of the following acid-base reactions: label each reactant as an acid or base label each product as a conjugate acid or conjugate base link the conjugate acid-base pairs a. HSO4- + NH3 SO42- + NH4+ d. b. HPO42- + NH4+ H2PO4- + NH3 e. c. SO32- + NH4+ HSO3- + NH3 f. H2PO4- + HCO3- HPO42- + H2CO3 F- + HSO4- HF + SO42HSO4- + H2O SO42- + H3O+ 4. What is meant by the conjugate acid of a base? 5. H2PO3- is an amphiprotic substance. Write two equations, one in which it acts like an acid, & one in which it acts like a base. (Hint: review your notes to determine what it could react with in each case). PH CALCULATIONS 1. What does pH stand for? 2. For each of the following, determine whether they are acidic or basic, & calculate the indicated value to the correct number of significant digits: a. Calculate the pH of a solution with [H3O+] = 0.00270 mol/L (2.569) b. [H3O+] in a cola drink is about 5.000 x 10-3 mol/L. Calculate the pH of the drink. (2.3010) c. A glass of orange juice has [H3O+] of 2.900 x 10-4 mol/L. Calculate the pH of the juice. (3.5376) d. [H3O+] of a solution of sodium hydroxide is 6.59 x 10-10 mol/L. Calculate the pH of the solution. (9.181) e. The pH of a solution is 3.34. What is the [H3O+]? (4.6 x 10-4 mol/L) f. Which of the above five questions is the strongest acid? Which is the weakest acid? PH & POH CALCULATIONS 1. What does pOH stand for? Given pH, how would you find pOH? 2. Calculate the pOH of a solution with [OH-] = 0.0125 mol/L. (1.903) 3. Calculate the [H+] of a solution with [OH-] = 2.5 x 10-6 mol/L. (4.0 x 10-9 mol/L) 4. Calculate the [OH-] of a solution with [H+] = 3.27 x 10-10 mol/L. (3.06 x 10-5 mol/L) 5. The pH of a solution is 1.20. What is the pOH? (12.80) 6. The pH of a solution is 4.00. What is the [OH-]? (1.0 x 10-10 mol/L) 7. The pOH of a solution is 7.50. What is the [H3O+]? (3.2 x 10-7 mol/L) 8. The pH of a solution is 3.15. What is the [OH-]? (1.4 x 10-11 mol/L) 9. The pH of a hydrochloric acid solution is 5.620. What is [HCl]? (2.40 x 10-6 mol/L) 10. The pOH of a magnesium hydroxide solution is 5.81. What is [Mg(OH)2]? 32 (7.7 x 10-7 mol/L) PH & STRONG ACID PROBLEMS 1. Define the following terms: a. Strong acid b. Weak acid c. Strong base d. Weak base 2. A student prepared 1250 mL containing 1.34 x 10-4 mol of nitric acid. What was the pH of the solution? (3.970) 3. A solution was prepared by bubbling 0.145 g of hydrochloric acid into enough water to make 1.75 L of solution. What was the pH of the acid? (2.643) 4. If 12.5 mL of hydrobromic acid with concentration 0.0500 mol/L was combined with enough water to make 2.00 L of solution, what was the pH? (3.505) 5. A student was asked to create 2.00 L of perchloric acid with a pH of 2.500. If the original stock solution had a concentration of 3.00 mol/L, what volume of stock would be required to prepare the solution? (2.11 mL) 6. A solution of hydroiodic acid had a pH of 4.500. It was prepared using 40.0 mL of stock solution with a concentration of 2.00 mol/L. What was the volume of the acid solution? (2.53 x 103 L) STRONG ACID & STRONG BASE TITRATION PROBLEMS 1. Describe or draw the apparatus needed for an acid-base titration experiment. Label all equipment & identify the purpose of each part of the titration set-up. 2. What happens to the chemicals during a titration? 3. What is the concentration of potassium hydroxide solution, KOH, if 12.8 mL of this solution is required to react with 25.0 mL of 0.110 mol/L sulphuric acid, H2SO4? (0.430 mol/L) 4. What volume of 0.125 mol/L calcium hydroxide, Ca(OH)2, is required to react completely with 15.0 mL of 0.100 mol/L sulphuric acid? (12.0 mL) 5. In a chemical analysis, a 10.0 mL sample of phosphoric acid, H3PO4, was reacted with 18.2 mL of 0.259 mol/L sodium hydroxide. Calculate the concentration of the phosphoric acid. (0.157 mol/L) 6. A student used a sodium hydroxide solution with concentration 0.100 mol/L to titrate 25.0 mL of hydrochloric acid with an unknown concentration. In three tests, the average volume of NaOH added was 14.65 mL. What was the concentration of the acid? (0.0586 mol/L) 7. A solution of KOH with a concentration of 0.0225 mol/L was used to titrate a 12.5 mL of HNO3 with an unknown concentration. The average volume of titrant was 13.27 mL. What was the concentration of the acid? (0.0239 mol/L) 8. A solution of nitric acid was prepared by mixing 15.0 mL of acid with 25.0 mL of water. The resulting solution was then titrated with sodium hydroxide with a concentration of 0.125 mol/L. The average volume of titrant added was 7.64 mL. What was the original concentration of the acid? (0.0637 mol/L) 9. A student mixed 12.5 mL of barium hydroxide solution with water to a final volume of 50.0 mL. The solution was titrated with 0.0250 mol/L hydrochloric acid. In three trials, the volumes of titrant added were 15.4 mL, 15.5 mL & 15.5 mL. What was the original concentration of the barium hydroxide solution? (0.0155 mol/L) 10. A solution of aluminum hydroxide was prepared by combining 10.5 mL of stock solution with 49.5 mL of water. The solution was titrated with 0.100 mol/L hydrochloric acid. The average volume of titrant added was 15.47 mL. What was the original concentration of aluminum hydroxide? (0.0491 mol/L) STRONG ACID & STRONG BASE NEUTRALIZATION PROBLEMS Note: the equivalence point may or may not have been reached… 1. 30.0 mL of 0.150 mol/L hydrochloric acid was added to 20.0 mL of 0.200 mol/L sodium hydroxide. Find the [OH -] of the resultant solution. (1.00 x 10-12 mol/L) 33 2. In a titration experiment, 25.0 mL of 0.100 mol/L HCl solution was used as the sample solution. The endpoint was overshot when 27.0 mL of 0.100 mol/L NaOH solution was added. What is the pH of the resultant solution? (11.585) 3. 30.0 mL of 0.150 mol/L HCl was added to 40.0 mL of 0.200 mol/L NaOH. Find the pH of the resultant solution. (12.699) 4. 45.0 mL of 0.100 mol/L hydrochloric acid was added to 10.0 mL of 0.150 mol/L calcium hydroxide. Find the [H +] of the resultant solution. (0.0273 mol/L) 5. 45.0 mL of 0.100 mol/L hydrochloric acid was added to 10.0 mL of 0.225 mol/L calcium hydroxide. Find the pH of the resultant solution. (7.000) 6. 50.0 mL of 0.150 mol/L hydrochloric acid was added to 20.0 mL of 0.200 mol/L aluminum hydroxide. Find the pH of the resultant solution. (12.808) 7. 30.0 mL of 0.150 mol/L phosphoric acid was added to 20.0 mL of 0.200 mol/L sodium hydroxide. Not all of the acid was neutralized. Find the pH of the resultant solution. (0.721) 8. 45.0 mL of 0.100 mol/L sulphuric acid was added to 10.0 mL of 0.150 mol/L aluminum hydroxide. Find the pH of the resultant solution. (1.09) GASES & ATMOSPHERIC CHEMISTRY UNIT PRESSURE & TEMPERATURE CONVERSIONS 1. Define pressure. 2. What does STP & SATP stand for? 3. Convert the following pressure values to kilopascals: a. 1.40 atm b. 0.987 atm c. 754 torr d. 792 mmHg 4. Convert the following pressure values to atmospheres: a. 105 kPa b. 9.57 x 103 Pa c. 745 torr d. 815 mmHg 5. Convert the following pressure values to mmHg or torr: a. 98.5 kPa b. 104 kPa c. 1.10 atm d. 0.975 atm Convert the following temperature values to degrees Celsius: a. 298 K b. 245 K Convert the following temperature values to Kelvin: a. 20.0°C b. -45.5°C 6. 7. BOYLE’S LAW PROBLEMS 1. A 50.00 cm3 sample of nitrogen gas is collected at 101.3 kPa. If the volume is reduced to 5.000 cm 3, & the temperature remains constant, what will the final pressure of the nitrogen be? (1013 kPa) 2. A weather balloon has a volume of 1.000 103 L at a pressure of 740.0 torr. The balloon rises to a height of 1.000 km where the atmospheric pressure is measured as 450.0 torr. Assuming there is no change in temperature, what is the final volume of the weather balloon? (1644 L) 3. A 45.0 cm3 sample of nitrogen gas is collected at 1.0 atm. The nitrogen is compressed to a pressure of 10.0 atm. What is the final volume of the nitrogen if the temperature remains constant? (4.5 cm3) 4. A 1.00 L helium balloon is floating in the air on a day when the atmospheric pressure is 102.5 kPa & the temperature is 20.0°C. Suddenly, clouds appear & the pressure rapidly drops to 98.6 kPa at a temperature of 20.0°C. By how much did the volume of the balloon increase? (3.96%) 34 5. 0.750 L of oxygen gas is trapped at 101.3 kPa in a cylinder with a moveable piston. The piston is moved & the gas is compressed to a volume of 0.500 L. What was the final pressure, in atm, that was applied to the oxygen gas if the temperature remains unchanged? (1.50 atm) CHARLES’ LAW PROBLEMS 1. Methane gas can be condensed by cooling & increasing the pressure. A 6.00 102 L sample of methane gas at 25.0°C & 1.00 102 kPa is cooled to -20.0°C. What will be the final volume? (509 L) 2. A sample of gas at 15.9°C is placed into a syringe. By what amount will the gas volume change (relative to the initial volume) after the gas is subjected to a temperature of 65.5°C? (1.17) 3. A sample of nitrogen gas has a volume of 0.400 L at 100°C. At what temperature will it have a volume of 0.200 L if the pressure does not change? (-86.6°C) 4. A 14.5 cm3 sample of oxygen gas at 24.3°C is drawn into a syringe with a maximum volume of 60.0 cm3. What is the maximum change in temperature that the oxygen can be subjected to before the plunger pops out of the syringe? (933°C) 5. A balloon is filled with 2.50 L of dry helium at 23.5°C. The balloon is placed in a freezer overnight. The next morning, the balloon is removed & the volume is found to be 2.15 L. What was the temperature (in °C) inside the freezer if the pressure remained constant? (-18.0°C) GAY-LUSSAC’S LAW PROBLEMS 1. A glass bottle has an internal volume of 0.50 L & contains air at STP. It will burst if the pressure of the trapped gas exceeds 5.5 atm. To what temperature can the bottle be heated before it bursts? (1.2 x 103°C) 2. A metal cylinder, which has a safety valve that opens at a pressure of 1.00 102 atm, it to be filled with nitrogen gas & heated to 300.0°C. What is the maximum pressure to which it can be filled at 25.0°C? (52.0 atm) 3. At 18.0°C, a sample of helium gas is stored in a metal cylinder exerts a pressure of 17.5 atm. What will the pressure become if the tank is placed in a closed room where the temperature increases to 40.0°C? (18.8 atm) 4. A cylinder of chlorine gas is stored in a concrete-lined room for safety. The cylinder is designed to withstand 50.0 atm of pressure. The pressure gauge reads 35.0 atm at 23.2°C. An accidental fire in the room next door causes the temperature in the storage room to increase to 87.5°C. What will the pressure gauge read at this temperature & will the cylinder explode? (42.6 atm) 5. A truck leaves Yellowknife in January when the temperature is -30.0°C. The tires of the truck are inflated to 210.0 kPa. Four days later, the truck arrives in California where the temperature is 30.0°C. What is the air pressure in the tires when the truck arrives? (262 kPa) 6. Before leaving on a trip to Florida, the pressure inside the tires of a car at a gas station was 206.5 kPa. The temperature was -7.50°C. The day after arriving in Florida, the tire pressure was 34.3 psi. Most pressure gauges in the United States are calibrated in psi. What is the approximate temperature in Florida? (1 psi = 6.894 kPa) (31.0°C) COMBINED GAS LAW PROBLEMS 1. A gas originally had a volume of 6.35 L at STP. If the conditions are altered to 400 mmHg & 25.0°C, what volume does the gas have now? (13.2 L) 2. Sandra had a birthday party on a winter day. She tied 4.2 L balloons to the front of the house. The temperature was -2.0°C & the pressure was 100.8 kPa. Unfortunately, the weather changed & a higher-pressure (103 kPa) cold front (-25°C) rushed into town. What will happen to the balloons after the weather change? (3.8 L) 3. A sample of gas has a volume of 150 mL at 260 K & 92.3 kPa. What will the new volume be at 376 K & 123 kPa? (0.16 L) 4. A cylinder at 48 atm pressure & 290 K releases 35 mL of carbon dioxide gas into a 4.0 L container at 297 K. What is the pressure inside the container? (0.43 atm) 35 5. An automated instrument has been developed to help drug-research chemists determine the amount of nitrogen in a compound. Any compound containing carbon, nitrogen & hydrogen is reacted with copper (II) oxide to produce carbon dioxide, water & nitrogen gases. The gases are collected separately & analyzed. In an analysis of 39.8 mg of caffeine using this instrument, 10.1 mL of nitrogen gas is produced at 23.0°C & 746 torr. What must the new temperature of the nitrogen gas be, in °C, if the volume is increased to 12.0 mL & the pressure is increased to 780 torr? (94.7°C) 6. A container of gas has a volume of 2.50 L. Its pressure is 450.0 mmHg & its temperature is unknown. The gas is now changed to a volume of 5.50 L at 650.0 mmHg & 30.0°C. Calculate what the initial temperature must have been. (-178°C) 7. A 3.84 mL sample of nitrogen gas at 23.0°C & 785 mmHg is cooled to 0.00°C. The pressure changes to 761 mmHg. What is the new volume? (3.65 mL) 8. A cylinder of gas has a volume of 135 L, a pressure of 15.0 atm & a temperature of 22.0°C. The gas now escapes into the room, which has a volume of 2.00 x 105 L. The temperature is lowered to 18.0°C. What is the pressure of the gas in this room? (9.99 10-3 atm) 9. A weather balloon with a volume of 55.0 L is filled with hydrogen gas at a pressure of 98.5 kPa & a temperature of 13.0°C. When the balloon is released, it rises to the stratosphere where the temperature is -48.0°C & the pressure is 19.7 kPa. What is the volume of the balloon under these conditions? (216 L) 10. A 10.1 mL sample of nitrogen gas is prepared at 23.0°C & 746 mmHg. If the volume changes to 9.14 mL & the pressure increases to 762 mmHg, what is the temperature of the gas? (0.599°C) IDEAL GAS LAW PROBLEMS 1. A 14.0 L balloon holds 2.04 moles of carbon dioxide gas at 259 kPa & 30.2°C. If 3.56 moles of carbon dioxide is placed at 800 torr & 45.0°C into a different balloon, what would be volume become? (62.2 L) 2. What mass of sulphur dioxide, SO2, is in 36.2 L of gas at 1.22 atm & 9.20°C? (122 g) 3. How many moles of gas are present in 11.2 L at SATP? How many molecules? (2.72 x 1023 molecules) 4. What is the volume of 3.45 mol of argon gas at SATP? (85.5 L) 5. A quantity of carbon dioxide gas has a volume of 19.5 L at a temperature of 400°C & a pressure of 23.8 atm. How many moles of carbon dioxide are present? What is the mass of the gas? (0.370 kg) 6. By how much will a balloon change (relative to the initial volume) when 39.2 g of oxygen gas at 492 kPa & 15.5°C is changed to contain 15.4 g at STP? (1.81) 7. An experiment calls for 3.50 mol of chlorine gas. What volume would this be if the gas is at 34.0°C & 2.45 atm? (36.0 L) 8. The maximum safe pressure that a certain 4.00 L container can hold is 355 kPa. If the container is filled with 0.410 mol of gas, what is the maximum temperature to which the container can be subjected? (143°C) 9. A 2.50 L flask was used to collect a 5.65 g sample of propane gas, C3H8. After the sample was collected, the gas pressure was found to be 956 mmHg. What was the temperature of the propane in the flask? (26.0°C) 10. What mass of oxygen gas is in a 50.0 L tank at 21.0°C when the pressure is 15.7 atm? (1.04 kg) IDEAL GAS LAW MOLAR VOLUME PROBLEMS Date: __________________________________________ 1. Manipulate the Ideal Gas Law to derive an equation to calculate the molar volume of a gas. 2. What is the molar volume of any gas at STP? (22.4 L/mol) 3. What is the molar volume of any gas at SATP? (24.8 L/mol) 36 4. What is the molar volume of oxygen gas at 19.0°C & 100.0 kPa? (24.3 L/mol) IDEAL GAS LAW MOLAR MASS PROBLEMS 1. Using the relationships n = m/M & the Ideal Gas Law, derive an equation to calculate the molar mass of a gas. 2. A 1.28 g sample of liquid was vapourized in a 250.0 mL flask at 121°C & 786 torr. What is the molar mass of the substance? (1.60 x 102 g/mol) 3. What is the molar mass of a gas, 0.842 g of which occupies 0.450 L at a pressure of 100.0 kPa & a temperature of 100.0°C? (58.1 g/mol) 4. A scientist isolates 2.366g of a gas. The sample occupies a volume of 800 mL at 78.0°C and 103 kPa. Which gas is it likely to be? (Kr) 5. As geologists study the area where an ancient marsh was located, they discover an unknown gas seeping from the ground. They collect a sample of the gas & take it to a lab for analysis. Lab technicians find that the gas is made up of 80.0% carbon & 20.0% hydrogen. They also find that a 4.60 g sample occupies a volume of 2.50 L at 1.50 atm & 25.0°C. What is the molecular formula of the gas? (C2H6) 6. A gas that consists of only nitrogen & oxygen atoms is found to contain 30.0% nitrogen. A 9.23 g sample of the gas occupies 2.20 L at STP. What is the gas? (N2O4) 1. Using the relationships n = m/M, d = m/V & the Ideal Gas Law, derive an equation to calculate the density of a gas. 2. The atmosphere consists largely of nitrogen gas. a. Calculate the densities of N2, Cl2 & He at 20.0°C & 101.3 kPa. (1.16 g/L, 2.95 g/L, 0.166 g/L) b. Explain why chlorine gas would appear as a yellow cloud creeping along the ground when it was used in World War I. c. Explain why helium balloons float. 3. Calculate the density of hydrogen sulphide gas, H2S, at 56.0°C & 967 mmHg. 4. An unknown compound has a density of 1.585 g/L at 90.0°C & 753 mmHg. What is the molar mass of the compound? (47.7 g/mol) 5. Oxygen gas makes up about 20.00% of the Earth’s atmosphere. Find the density of pure oxygen gas, in g/L, at 12.50°C & 126.63 kPa. (1.706 g/L) 6. On Mars, the atmosphere has a pressure of about 15.0 torr. The daytime temperature is about -40.0°C. How many moles are there in 1.00 L of this atmosphere? How many molecules is this per litre? (6.21 x 1020 molecules/L) IDEAL GAS LAW DENSITY PROBLEMS (1.61 g/L) GAS STOICHIOMETRY CALCULATIONS 1. Ammonia, NH3, is produced by a reaction of nitrogen gas, N2, & hydrogen gas, H2. Suppose that 12.0 L of nitrogen gas reacts with hydrogen gas & produces ammonia, all at the same temperature & pressure. What volume of ammonia is produced? What volume of hydrogen is consumed? (24.0 L, 36.0 L) 2. Water vapour is produced when hydrogen gas, H2, is reacted with oxygen gas, O2. What volume of water vapour can be produced if 40 L of hydrogen gas is mixed with 15 L of oxygen gas to produce water vapour, all at the same pressure & temperature? What volume of the excess gas will remain? (30 L, 10 L) 3. Calcium carbide, CaC2, reacts with water to produce acetylene (C2H2) & calcium hydroxide, Ca(OH)2. Calculate the volume of acetylene produced at 26.0°C & 104 kPa from 10.2 g of calcium carbide & excess water. (3.81 L) 4. Lithium hydroxide, LiOH, is used in spacecraft to absorb carbon dioxide, CO2, exhaled by astronauts, which then produces lithium carbonate, Li2CO3, & water. What volume of carbon dioxide at 21.1°C & 1.15 atm could be absorbed by 348 g of lithium hydroxide? (153 L) 37 5. A 24.9 mL sample of hydrochloric acid, HCl, reacts with excess sodium carbonate, Na2CO3, to produce carbon dioxide, CO2, water & sodium chloride, NaCl. The volume of carbon dioxide formed is 141 mL at 27.0°C & 742 torr. What is the molar concentration of hydrochloric acid? (0.449 mol/L) 6. Methanol, CH3OH, has potential to be used as an alternative fuel. It burns in the presence of oxygen, O2, to produce carbon dioxide, CO2, & water. 10.0 L of oxygen gas is completely consumed at 775 torr & 35.1°C. What volume of carbon dioxide at 750 torr & 23.4°C is produced? (6.63 L) 7. When ammonia, NH3, & oxygen, O2, react, they produce nitrogen monoxide, NO, & water. What volume of oxygen gas at 35.0°C & 2.15 atm is needed to produce 46.1 g of nitrogen monoxide? (22.6 L) 8. Magnesium nitride reacts with water to produce ammonia gas & magnesium hydroxide solid. What volume of ammonia gas at 24.0°C & 743 mmHg will be produced from 4.56 g of magnesium nitride? (2.25 L) DALTON’S LAW OF PARTIAL PRESSURES PROBLEMS 1. To speed up a reaction in a vessel pressurized at 98.0 kPa, a chemist added 202.65 kPa of hydrogen gas. What was the resultant pressure? (301 kPa) 2. A gas mixture contains 12% neon, 23% helium & 65% radon. If the total pressure is 116 kPa, what is the partial pressure of each gas? (14 kPa, 27 kPa, 75 kPa) 3. A mixture of nitrogen & carbon dioxide gas is at a pressure of 1.00 atm & a temperature of 278 K. If 30.0% of the mixture is nitrogen, what is the partial pressure of the carbon dioxide? (0.700 atm) 4. The partial pressure of argon gas, making up 40.0% of a mixture, is 325 torr. What is the total pressure of the mixture in kPa? (108 kPa) 5. A mixture of non-reactive gases in a 5.00 L flask at 15.0°C includes 0.835 g of xenon gas. What is the partial pressure of xenon? (3.05 kPa) 6. A 200.0 mL flask contains 1.03 mg of oxygen gas & 0.410 mg of helium gas at 15.0°C. Calculate the total pressure in the flask. (1.61 kPa) 7. A 1.00 L sample of a gas mixture contains nitrogen gas & oxygen gas at 25.0°C. The mass of nitrogen gas is 1.05 g, & the total pressure in the flask is 115 kPa. What is the partial pressure of oxygen in the flask? (22.1 kPa) 8. The atmosphere in a sealed diving bell with a volume of 1.00 L contains oxygen gas & helium gas at 20.0°C. If the gas mixture has 0.200 atm of helium & a total pressure of 3.00 atm, calculate the mass of oxygen. (3.72 g) WATER VAPOUR PRESSURE PROBLEMS 1. In an experiment, 0.750 L of hydrogen gas is collected over water at 25.0°C & 101.6 kPa. What volume will the dry hydrogen occupy at 103.3 kPa & 25.0°C? (0.715 L) 2. A chemist collects 8.15 L of oxygen gas, collected over water, at 22.0°C & 105.0 kPa. What mass of oxygen gas was collected? (10.9 g) 3. Formic acid, HCOOH, can decompose to form carbon monoxide gas, CO, & liquid water. If 3.85 L of CO was collected by downward displacement of water at 25.0°C & 689 mmHg, how many grams of formic acid were reacted? (6.34 g) 4. Ammonium nitrite, NH4NO2, decomposes to produce nitrogen gas & liquid water. What mass of ammonium nitrate needs to react if 4.10 L of nitrogen gas were collected over water at 19.0°C & 97.8 kPa? (10.3 g) 5. Magnesium metal reacts with excess dilute hydrochloric acid, HCl, to produce hydrogen gas & aqueous magnesium chloride, MgCl2. Suppose 0.150 g of magnesium metal was used & the hydrogen gas is collected over water at 28.0°C & 101.8 kPa. What volume will the hydrogen occupy? (0.158 L) 38 REFERENCE MATERIAL CONVERSION FACTORS FOR CALCULATIONS 1 metre (m) = 100 centimetres = 1000 millimetres = 39.370 inches 1 centimetre (cm) = 10 millimetres (mm) = 0.39370 inches 1 Angstrom (A) = 10-8 cm 1 micron (µ) = 10-3 millimetre 1 kilogram (kg) = 1000 grams = 2.2046 pounds 1 gram (g) = 1000 milligrams (mg) 1 atomic mass unit (amu) = 1.6604 x 10-24 g 1 litre (L) = 1000 millilitres (mL) = 1.0567 quarts 1 gallon (gal) = 3.7854 L 1 cubic inches (in3) = 16.387 mL 1 cubic foot (ft3) = 28317 mL 1 electron volt (eV) = 1.6021 x 10-12 erg = 23.061 kcal/mol 1 calorie (cal) = 4.1840 x 107 erg 1 joule = 1 x 107 erg °C = 5/9(F – 32) Kelvin = °C + 273.15 1 atm = 760 mmHg = 13.6 x 760 mmH2O CONSTANTS (assume all constants have infinite number of significant digits) R = 8.3145 L.kPa/mol.K R = 0.08206 L.atm/mol.K NA = 6.023 1023 particles/mol KW = 1 10-14 at 25.0°C USEFUL FORMULAS (not all formulas may be used) m = nM N = nNA massofcomponent %composition 100% totalmolarmass exp erimentalyield 100% theoreticalyield pureyield % purity 100% impuresample % yield m % massofsolute( g ) 100% m massofsolution( g ) v % volumeofsolute(mL) 100% v volumeofsolution (mL) C1V1 = C2V2 Kw = [H+][OH-] pH = -log[H+] pOH = -log[OH-] V1 V2 P1 P2 T1 T2 T1 T2 PV = nRT n = CV massofsolu te( g ) m % 100% V volumeofsolution (mL) massofsolute( g ) 10 6 massofsolution( g ) massofsolute( g ) ppb 10 9 massofsolution( g ) massofsolute( g ) so lub ility 100mLofsolution ppm pH + pOH = pKw KaKb = Kw [ A ] pH pK a log [ HA] P1V1 = P2V2 P1V1 P2V2 T1 T2 Ptotal = P1 + P2 + … Mass # = # protons + # neutrons Average Atomic Mass = (%abundance)(isotopicmass) formal charge = valence electrons – ½(bonding pair electrons) 39 P1 P2 T1 T2 USEFUL POLYATOMIC IONS Formula NH4+ CH3COO- or C2H3O2BrO3CNOH- Name ammonium acetate bromate cyanide hydroxide Formula MnO3CrO42Cr2O72AsO43- Name manganate chromate dichromate arsenate METAL & HALOGEN ACTIVITY SERIES Metal Activity Series: Li K Ba Ca Na Mg Al Zn Cr Fe Cd Co Ni Sn Pb H Cu Hg Ag Pt Au A possible phrase which may help memorize this list goes as follows: “Linda, please bring Carmen Sandiego more awesome zebra crackers in ceramic containers, not the large heavy crate marked striped perishable goods!” Halogen Activity Series: F Cl Br I Each element in an activity series (metal or halogen) will displace any element listed below it in the same series. In the metal activity series, hydrogen is included, even though it is not a metal, because it forms positively charged ions like metals do. Many metals will therefore displace hydrogen from compounds such as water or acids. Metals listed below hydrogen do not react with water or acids. SOLUBILITY TABLE @ SATP (other versions are possible) High Solubility (>0.1 mol/L at SATP) Cl-, Br-, I- S2- OH- SO42- CO32-, PO43-, SO32- CH3COO- NO3- ClO3- O2- most Group 1, NH4+, Group 2 Group 1, NH4+, Sr2+, Ba2+, Tl+ most Group 1, NH4+ most all most Group 1, NH4+, Ba2+ Ag+, Pb2+, Ca2+, Ag+, Pb2+, Ba2+, Tl+, Hg2+, most most most Ag+ none Ca2+ Sr2+, + Cu Hg2+, Ra2+ All Group 1 compounds, including acids & all ammonium compounds are assumed to have high solubility in water Low Solubility (<0.1 mol/L at SATP) Cations Anions 40 most WATER VAPOUR PRESSURE TABLE Temperature (°C) 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 Vapour Pressure (kPa) 0.61 0.66 0.71 0.76 0.81 0.87 0.93 1.00 1.07 1.15 1.23 1.31 1.40 1.50 Temperature (°C) 14.0 15.0 16.0 17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0 25.0 26.0 27.0 Vapour Pressure (kPa) 1.60 1.70 1.82 1.94 2.06 2.20 2.34 2.49 2.64 2.81 2.98 3.17 3.36 3.57 41 Temperature (°C) 28.0 29.0 30.0 31.0 32.0 33.0 34.0 35.0 36.0 37.0 38.0 39.0 40.0 Vapour Pressure (kPa) 3.78 4.01 4.24 4.49 4.75 5.03 5.32 5.62 5.94 6.27 6.62 6.99 7.37 PERIODIC TABLE (Electronegativities, Common Valences, Atomic Masses) 1 (IA) 1 18 (VIIIA) 2.20 H 2 1+, 1- Hydrogen 1.01 3 0.98 Li 1+ Lithium 6.94 11 0.93 Na 1+ Sodium 22.99 19 0.82 K 1+ Potassium 39.10 37 0.82 Rb 1+ Rubidium 85.47 55 0.79 Cs 1+ Cesium 132.91 87 0.70 Fr 1+ Francium 223.02 0 He 2 (IIA) 4 Legend Atomic # 1.57 Be 2+ Symbol 2+ Calcium 40.08 38 0.95 Sr 2+ Strontium 87.62 56 0.89 Ba 2+ Barium 137.33 88 0.90 Ra Radium 226.03 5 Most stable valence is bolded 2+ 14 (IVA) 2.04 3+ B Atomic Name Atomic Mass Boron 10.81 13 1.61 2+ Magnesium 24.31 20 1.00 Ca EN Common Valences Beryllium 9.01 12 1.31 Mg 13 (IIIA) 3+ 3 (IIIB) 21 4 (IVB) 1.36 Sc 3+ Scandium 44.96 39 1.22 3+ Y Yttrium 88.91 71 1.27 Lu Lutetium 174.97 103 Lr 2+ 3+ 22 5 (VB) 1.54 Ti 3+, 4+ Titanium 47.88 40 1.33 4+ Zr Zirconium 91.22 72 1.30 4+ Hf Hafnium 178.49 104 23 6 (VIB) 1.63 2+, 3+, 4+, 5+ 24 7 (VIIB) 1.66 2+, 3+, 6+ V Cr Vanadium 50.94 41 1.60 Chromium 52.00 42 2.16 3+, 5+ Nb Niobium 92.91 73 1.50 5+ Ta Tantalum 180.95 105 2+, 3+, 4+, 5+, 6+ 25 8 (VIIIB) 1.55 2+, 3,+, 4+, 6+, 7+ 27 1.88 2+, 3+ 28 11 (IB) 1.91 2+, 3+ Mn Fe Co Ni Iron 55.85 44 2.20 Cobalt 58.93 45 2.28 Nickel 58.69 46 2.20 Mo Tc Technetium (98.91) 75 1.90 1-, 2+, 4+, 6+, 7+ W Tungsten 183.85 106 1.83 2+, 3+ 10 (VIIIB) Manganese 54.94 43 1.90 Molybdenum 95.94 74 2.36 2+, 3+, 4+, 5+, 6+ 26 9 (VIIIB) Re Rhenium 186.21 107 2+, 3+, 4+, 6+, 8+ 2+, 3+, 4+ 2+, 4+ 29 12 (IIB) 1.90 1+, 2+ Zn Zinc 65.39 48 1.69 1+ Rh Pd Ag Rhodium 102.91 77 2.20 Palladium 106.42 78 2.28 Silver 107.87 79 2.54 Os Osmium 190.23 108 Ir Iridium 192.22 109 Pt 2+, 4+ Platinum 195.88 110 2+ Cu Ru 2+, 3+, 4+, 6+ 1.65 Copper 63.55 47 1.93 Ruthenium 101.07 76 2.20 2+, 3+, 4+, 6+, 8+ 30 1+, 3+ Cd Cadmium 112.41 80 2.00 1+, 2+ Au Gold 196.97 111 2+ 2.55 4+ C Carbon 12.01 14 1.90 4+ Al Si Aluminum 26.98 31 1.81 Silicon 28.09 7 16 (VIA) 3.04 3- N Nitrogen 14.01 15 2.19 3- P 2.01 Phosphorus 30.97 33 2.18 Gallium 69.72 49 1.78 Germanium 72.61 50 1.96 Arsenic 74.92 51 2.05 In Sn Ga 3+ 3+ Indium 114.82 81 2.04 1+, 3+ Hg Mercury 200.59 112 6 15 (VA) 32 4+ Ge 2+, 4+ Tin 118.71 82 2.33 Tl Pb Thallium 204.38 Lead 207.2 2+, 4+ 3- As Sb 3+, 5+ Antimony 121.75 83 2.02 Bi 3+, 5+ Bismuth 208.98 114 8 3.44 2- O Oxygen 16.00 16 2.58 2- S Sulphur 32.07 34 2.55 2- Se Selenium 78.96 52 2.10 2- Te Tellurium 127.60 84 2.00 Po 2+, 4+ Polonium (208.98) 116 Rf Db Sg Bh Hs Mt Ds Rg Cn Fl Lv Lawrencium (260.11) Rutherfordium (261.11) Dubium (262.12) Seaborgium (263.12) Bohrium (262.12) Hassium (264) Meitnerium (266.14) Darmstadtium (269) Roentgenium (272) Copernicium (277) Flerovium (285) Livermorium (289) 57 58 63 64 65 66 1.10 La 3+ 1.12 59 1.13 60 1.14 61 1.13 62 1.17 2+, 3+ 1.20 2+, 3+ 1.20 3+ 1.20 3+, 4+ 1.22 3+ 67 1.23 68 1.24 69 1.25 70 1.11 Eu Gd Tb Dy Europium 151.96 95 1.30 Gadolinium 157.24 96 1.30 Terbium 158.93 97 1.30 Dysprosium 162.50 98 1.30 Holmium 164.93 99 1.30 Erbium 167.26 100 1.30 Thulium 168.93 101 1.30 Ytterbium 173.04 102 1.30 Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Americum 243.06 Curium 247.07 Berkelium 247.07 Californium 251.08 Actinium 227.03 Thorium 232.04 Protactinium 231.04 Uranium 238.03 Neptunium 237.05 Plutonium 224.06 42 3+ 3+, 4+ 3+ 3+ Einsteinium 252.08 Fermium 257.10 3+ 2+, 3+ Mendelevium 258.10 Yb 2+, 3+ Sm 3+, 4+, 5+, 6+ Tm 2+, 3+ Samarium 150.36 94 1.28 3+, 4+, 5+, 6+ Er 3+ Promethium 144.91 93 1.36 3+, 4+, 5+, 6+ Ho 3+ Neodymium 144.24 92 1.38 3+, 4+, 5+, 6+ Pm 3+ Praseodynium 140.91 91 1.50 4+, 5+ Nd 3+ Cerium 140.12 90 1.30 4+ Pr 3+, 4+ Lanthanum 138.91 89 1.10 3+ Ce 3+, 4- 17 (VIIA) 2+, 3+ Nobelium 259.10 9 Helium 4.00 3.98 F 1- Fluorine 19.00 17 3.16 1- 10 0 Ne Neon 20.18 18 0 Cl Ar Chlorine 35.45 35 2.96 Argon 39.95 Br 1- Bromine 79.90 53 2.66 I 1- Iodine 126.90 85 2.20 At Astatine (209.99) 1- 36 0 Kr Krypton 83.80 54 0 Xe Xenon 131.29 86 0 Rn Radon (221.02)