Welcome to Advanced Placement Chemistry 2015-2016!
Thank you for having the courage and motivation to continue on past
Chemistry I and into a higher college-level exploration and analysis of the
interactions within our world. I am certain you will find the material to be not
only rigorous and challenging, but also rewarding, as you prepare for the AP exam
and further studies in college and the real world beyond.
This summer assignment is lengthy and comprehensive. It is not designed to
be completed all at once, or even in a compressed time period. Give yourself
plenty of time and multiple sessions to complete it. I recommend typing the
written portions of this assignment. If you do decide to hand-write it, please keep
it neat. You will likely need to refer to your notes and do some research and
“brushing up” of certain skills and concepts. Print yourself out a Periodic Table of
the Elements that you can use. There are plenty on line.
The assignment includes a number of problems of varying complexity,
representative of what was covered in Chemistry I. In most cases, I have provided
the answers, so that you can check yourself. However, all work must be shown. If
you get the same answer as the one given, you still must show me how you
arrived at that answer. Show all pertinent steps (simple steps that were obviously
done on a calculator may be omitted.) Again, my recommendation is to keep
things neat. This will help you keep things straight on problems with multiple
steps, and it will help me understand how you arrived at your solution.
Good luck, enjoy your summer, and pace yourself!
J. Miller and K. Talopau
Advanced Placement Chemistry Summer Assignment 2015
Overview: This multi-part assignment includes certain concepts over which the student will need to
demonstrate mastery by the beginning of AP Chemistry. An assessment on those concepts will occur
very early on in the course. This assignment also includes some problems on various concepts which are
fundamental to basic chemistry, and several writing activities. This assignment is due by the end of the
first week of class to allow for schedule changes. It is highly recommended that the student finish the
assignment completely before classes begin!
Section I: These questions will need to be answered in paragraphs. Please use complete sentences,
correct grammar and spelling, and proper paragraph form. It may be neatly written or typed. I
encourage you to use your notes and/or on-line resources to help you formulate your answers. Please
read carefully and answer all parts of the question!
1. Describe the structure of the atom with regard to protons, neutrons, and electrons. Tell me
where each of those subatomic particles is located, their relative charge, and their relative mass.
What model of the atom is currently the most accurate as far as we know?
2. Explain the difference between ionic and covalent bonding. What types of elements participate
in which bonding scenarios? Give at least one example of each type, and include a correctly
labeled diagram of each type. What are some physical characteristics of ionic and covalent
compounds? What are the representative particles of elements, ionic compounds, and covalent
compounds called?
3. Explain the rules of nomenclature (naming) for ionic and covalent compounds, remembering to
address the appropriate presence or absence of prefixes. Give three correctly written examples
of each type, along with their formulas.
4.
Define a mole of a substance. Your explanation should address the following: atomic mass,
Avogadro’s number, and representative particles. How is using the mole in calculations more
convenient that simply using the number of particles of a substance?
5. Define the five main types of chemical reactions (exclude acid-base) and explain what is
happening in each one. Write one correctly balanced equation for each type. Make sure you
include certain characteristics of the reactions, such as common reactants/products and
metal/non-metal combinations.
6. Explain the Law of Conservation of Matter, and how it applies to correctly balancing the
equations for chemical reactions. Your answer should mention coefficients and what they
represent.
7. Explain the difference between theoretical (stoichiometric) yield and actual (empirical) yield.
What are some factors contributing to this difference?
8. Distinguish between an exothermic reaction and an endothermic reaction. Your answer should
address how heat is released and absorbed with a system’s surroundings. Your answer should
also mention the change in potential energy (enthalpy) between the reactants and the products
for both types. You may include properly labeled diagrams with your answer.
9. Contrast the three main intermolecular forces (IMFs.) Give at least one example of a substance
that exhibits each of three IMFs as its primary intermolecular attraction.
10. What are the assumptions made by the Ideal Gas Law? What is STP?
11. Define electronegativity and describe its trend on the Periodic Table. Name two compounds
whose constituent elements exhibit a high electronegativity difference, and two compounds
whose constituent elements exhibit a low electronegativity difference. (Make sure the
substances are chemically possible!)
12. Explain what it means when a system is in dynamic equilibrium.
13. Explain why the atomic mass given for most elements on the Periodic Table is not a whole
number.
14. Distinguish between a limiting reagent and an excess reagent. Which one determines how
much product is formed in a reaction and why?
15. Explain VSEPR (valence shell electron pair repulsion) theory. Draw Lewis structures for the
following molecules: Cl2, O2, N2, NH3, H2O, CH4. Which species are polar and which are non-polar
and explain how you can tell this from their correctly drawn structures. Identify their geometric
shapes. Show all unshared electron pairs as well as covalent bonds.
Section II: A whole bunch of problems. Solve them, and please show all work. I will include the correct
answer so that you can check your outcome. However, please show me how you got there – I will not
accept it without seeing your steps and calculations.
1. Percent composition. The greenish colored mineral malachite, Cu2CO3(OH)2, is a common ore of
copper. What is the percent composition of copper in malachite? (answer: approx. 58%)
2. Mole stoichiometry. How many moles of carbon dioxide are produced from the complete
combustion of heptane (C7H16) in 12.5 moles of oxygen? Assume you have an excess of
heptane.
(answer: 7.95 moles of CO2)
3. Mass stoichiometry. The equation for the decomposition of lead (II) nitrate is:
Pb(NO3)2 --> PbO + NO2 + O2 (this equation is not balanced.) How many grams of oxygen are
produced when 11.5g NO2 is formed?
(answer: 2g O2)
4.
Percent yield. In the above reaction, what is the percent yield if 9.9g lead (II) nitrate produces
5.5g of lead (II) oxide?
(answer: approx. 82%)
5. Moles/grams/liters/particles conversions: Solve the following. Assume STP in all scenarios.
Remember, 1 mole=22.4L=6.02x1023 representative particles.
a. How many moles are in 3.6g of colchicine (C22H25NO6)? (answer: 0.009mol)
b. What is the mass in grams of 56.0L of helium gas? (answer: 10g He)
c. What is the volume in liters of a balloon containing 9.5x1022 molecules of fluorine gas?
(answer: 3.58L)
d. How many formula units of calcium phosphide are in a sample weighing 1g? (answer:
3.31x1021 formula units)
6. Reactions. Predict the products of the following reactions and balance the equations.
a.
b.
c.
d.
Chlorine gas is bubbled through an aqueous solution of sodium bromide.
Octanol (C8H15OH) is completely combusted.
Vanadium metal (+5 valence) is exposed to nitrogen gas.
A solution of nickel (II) acetate reacts with a solution of phosphoric acid. (the acetate poly is
C2H3O2 with a -1 charge.)
e. Write the complete and net ionic equation for the reaction of aqueous solutions of silver
nitrate and sodium chloride which produce a silver chloride precipitate, AgCl(s).
7. Gas laws. Solve the following using either the combined gas law (P1V1/T1=P2V2/T2) or the ideal
gas law (PV=nRT, with R=0.0821 and n=number of moles).
a. I have added 15,000mL of air to a balloon at sea level. If I travel to Flagstaff, Arizona, where
the air pressure is 0.85atm, what will the balloon’s new volume be? (answer: 17.65L)
b. If I have 500mL of gas at a pressure of 1atm and a temperature of 15 degrees Celsius, and I
change the temperature to 3 degrees Celsius and the pressure to 150atm, what will the new
volume be in milliliters? (answer: 3.2mL)
c. How many moles of nitrogen are there in a sealed 125mL Erlenmeyer flask if the pressure is
2.53atm and the temperature is 20 degrees Celsius? (answer: 0.013mol)
d. If I react 100g of calcium fluoride with excess chlorine gas, I will yield a common salt plus
another gas. If I capture this gas in a 2,500mL vessel at a temperature of -10 degrees
Celsius, what will be the pressure inside the flask? If the flask bursts above 10atm pressure,
is this a safe reaction? (answer: approx. 11atm; no, it is unsafe)
e. Show proof that 1 mole of any gas occupies a certain constant volume at standard
temperature and pressure. (Use the ideal gas law equation!)
f. Gay-Lussac’s Law expresses the direct relationship between temperature and pressure.
Why does temperature vary directly with pressure? How is this a part of the kinetic
molecular theory? Your answer should include a discussion about kinetic energy and
collisions with the walls of the container. Assume a constant volume.
8. Solutions/acids and bases. Answer/solve the following problems.
a. a-1: Write and balance the acid-base reaction equation for the combination of hydrochloric
acid and sodium hydroxide.
a-2: How are all the products of acid-base reactions similar?
a-3: Why is an acid-base reaction often referred to as a neutralization reaction?
b. What is the definition of a 1.0 molar solution?
c. What is the molarity (M) of a solution of 45g of ammonia (NH3) dissolved in 750mL of water?
Use M=moles solute/liters solvent (H2O) (answer: 3.53M)
d. How many grams of ammonium sulfate are needed to make a 0.25L solution at a
concentration of 6M? (answer: approx. 200g)
e. Explain the difference between a strong acid and a weak acid. Your answer should mention
the difference between concentration and whether the substance is “strong” or “weak.”
Your answer should also define ionization or dissociation (they mean the same thing.)
f.
Which two of the following solutions have the same pH?
1. [H+] = 1.0x10-3M
pH=-log[H+]
2. [H+] = 1.0x10-11M
[H+][OH-]=1.0x10-14 (for water)
-4
3. [OH ] = 1.0x10 M
4. [OH-] = 1.0x10-3M
(answer: solutions 2 and 4 have the same pH, 11. They are equally basic.)
**In AP chem., we will be doing calculations for pH where the number going into the scientific
notation is not 1.0, which means you can’t accurately “short-cut” it without a scientific calculator.
12. Ionization energy. A mystery element has a first ionization energy of 265kJ, a second ionization
of energy of 984kJ, and a third ionization energy of 1,027kJ. Explain why this element could be sodium,
but is probably not magnesium.
13. Enthalpy. Given the reaction: 2H2 + O2  2H2O, and an enthalpy of -571.6kJ, what would be the
enthalpy if you did the reaction with 16.5 liters of hydrogen gas at STP? (Remember, 1 mole = 22.4L @
STP)
(answer: -211.5kJ)
14. Empirical/molecular. The compound sodium azide is used as a reactant in airbags. A sample of
it consists of 35.4% sodium and 64.3% nitrogen. a. What is sodium azide’s empirical formula? b. If
5mol of sodium azide has a mass of 325.0g, what is its molecular formula?
(answer: NaN3 for both)
15. Wavelength/frequency. The frequency of blue light is 6.67x1014Hz (cycles per second.) What is
the wavelength, in meters, of this light? Remember, the speed of light, a universal constant, is equal to
the product of wavelength and frequency.
(speed of light, c=3.0x108m/s)
(answer: 4.5x10-7m, or
450nm)
RUBRIC:
4.0– all questions and problems completed with all work neatly shown and in correct format.
3.0 – most questions and problems completed; some work not shown; some incorrect formatting and minor
neatness issues.
2.0 – quite a few incomplete questions and problems; substantial lack of work shown; portions of the
assignment sloppily written and/or work shown difficult to follow.
1.0 – very few questions and problems attempted; serious neatness issues.
0.0 – you’re a knucklehead and didn’t do it.