Unit 5 Packet
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Name WPHS Chemistry Unit 5 Packet Stoichiometry Bergmann-Sams -1- Name Chemistry: Unit 5 Outline: Stoichiometry Assignment Podcast 5.1 (CB 1-5) Worksheet A Lab: Simple Weight Loss Podcast 5.2 (CB 7-9) Worksheet B Podcast 5.3 (CB 11-13) Worksheet C Lab: Balloons—Vinegar—NaHCO3 Podcast 5.3 (CB 11-13) Worksheet D Lab: Limiting Reactants Stoichiometry Technology Lab Worksheet E Take Home Lab (Cookies) Worksheet F (Review) Lab Exam Unit 5 Exam) WB Page Number Online Pg 15-16 Pg 8-11 Online Pg 17-19 Online Pg 20-23 Pg 12-14 Online Pg 24-25 Pg 10-11 Teacher Handout Pg 26 Pg 6-7 Pg 27-29 In Class In Class Score Out of 100 100 100 100 100 100 100 100 (You must score 85/100 on all assignments with a number to move to the next unit. For those assignments with a check, you need to do it to the satisfaction of your teacher) -2- Name Unit 5: Stoichiometry—Composition Book Outline Section 9.1: The Arithmetic of Equations Introduction to Stoichiometry (pg 237-240) 1 Define: Stoichiometry Copy: Figure 9.2: The equation and diagram to make a tricycle Read: The whole section and write a 3-4 sentence summary of what we will be doing in this chapter Copy: Figure 9.4 on page 239: You may be brief as you do this. 9.2: Chemical Calculations Mole-Mole Calculations (pg 242-244) 3 Copy down the equation for the production of ammonia on page 242 and also all of the mole ratios (fractions) on the bottom of pg 242 Example 1 2KClO3 2 KCl + 3O2 When 2.2 moles of KClO3 reacts. How many moles of oxygen are formed? Example 2 2KClO3 2 KCl + 3O2 When 0.0045 moles of KCl is formed, how many moles of KClO 3 reacted? 5 Mass-Mass Calculations (pg 244-247) Example 1 2KClO3 2 KCl + 3O2 If 12.3 g of KClO3 reacts: How many grams of O2 will be formed? Example 2 2KClO3 2 KCl + 3O2 If 4.53 g of KClO3 reacts: How many liters of O2 will be formed? 7 Other Stioiciometric Calculations (pg 247-250) Example 1 2KClO3 2 KCl + 3O2 If 5.67 L of O2 is formed: How many molecules of KCl will be formed? Example 2 2CaCO3 + 2SO2 + O2 2CaSO4 + 2CO2 If 5.67 x 1023 molecules of O2 reacts: How many liters of CO2 will be formed Example 3 15.8 grams of AgNO3 is added to excess barium chlorde. How many grams of AgCl will be formed? Example 4 0.025 L of oxygen gas reacts with propane (C3H8). How many Liters of carbon dioxide is formed? -3- Name 9 More Stioiciometric Calculations (pg 247-250) Example 5 5.4 grams of Lithium reacts with a solution of Cobalt II phosphate. How many grams of cobalt is formed? Example 6 Iron III Nitride decomposes into its elements. If 4.5 x 10 5 grams of iron III nitride decomposes, how many liters of nitrogen gas will be formed at STP? Example 7 12.3 g of lead II nitrate reacts with an excess of sodium phosphate. How many grams of precipitate is formed? Example 8 2.3 x 1023 molecules of oxygen gas is formed in the decomposition of potassium chlorate. How many grams of potassium chlorate decomposed. The other product in the reaction is potassium chloride 9-3: Limiting Reagent and Percent Yield 11 Limiting Reagent (pg 252-256) Define: limiting reagent, excess reagent Example 1 2Hg(l) + O2(g) ---> 2HgO(s) 20.0 g of Hg are reacted with 5.00 g of O2. Calculate the maximum amount, in grams, of HgO formed. Example 2 2 Al + 3 I2 2 AlI3 Determine the limiting reagent and the amount of AlI3 produced in the reaction when 1.20 g Al and 2.40 g iodine react. How many grams of Al are left over? Example 3 90.0 g of FeCl3 reacts with 52.0 g of H2S. What is the limiting reactant? What is the mass of HCl produced? What mass of excess reactant remains after the reaction? -4- Name 13 More Limiting Reagent Problems Example 4: 3 FeO(s) + 2 Al(s) 3 Fe(s) + Al2O3 (s). A mixture of 10.325 g of iron(II) oxide and 5.734 g of aluminum metal is placed in a crucible and heated in a high-temperature oven, as expressed by the reaction above: (a) What is the limiting reagent? (b) Determine the maximum number of grams of Fe that can be produced. (c) Calculate the mass of the excess reactant remaining in the crucible. Example 5: 2NH3(g) + 3CuO(s) N2(g) + 3Cu(s) + 3H2O(g). Nitrogen gas can be prepared by passing ammonia gas over solid copper(II) oxide at high temps, as shown by the balanced equation above. If a sample containing 18.1g of NH3 is reacted with 90.4g of CuO. a) Which is the limiting reagent? b) How many Liters of N2 should be formed at STP? 15 Percent Yield (pg256-260) Define: theoretical yield, actual yield, percent yield Copy: The percent yield equation Example 1 A student adds 200.0g of C7H6O3 to an excess of C4H6O3, this produces C9H8O4 and C2H4O2. Calculate the percent yield if 231 g of aspirin (C9H8O4) is produced. C7H6O3 + C4H6O3 C9H8O4 + C2H4O2 Example 2 According to the following equation, Calculate the percentage yield if 550.0 g of toluene (C7H8 )added to an excess of nitric acid (HNO3) provides 305 g of the p-nitrotoluene (C7H7NO2 ) product. C7H8 + HNO3 C7H7NO2 + H2O 17 More Percent Yield Problems Example 3 Aluminum reacts with an aqueous solution containing excess copper (II) sulfate. If 1.85 g Al reacts and the percentage yield of Cu is 56.6%, what mass of Cu is produced? Al + CuSO4 Cu + Al2(SO4)3 Example 4 The combustion of methane produces carbon dioxide and water. Assume that 2.0 mol of CH4 burned in the presence of excess air. What is the percentage yield if the reaction produces 87.0 g of CO2? Example 5: 15.3 grams of Lithium is dropped into a solution containing 23.4 grams of copper II phosphate. When the reaction is completed, 1.25 grams of copper is formed. What is the percent yield? -5- Name Take Home Lab: Making Chocolate Chip Cookies Name The following recipe for chocolate chip cookies recently appeared in Chemical & Engineering News (C&EN, Jun 19, 1995, p. 100). It was attributed to Jeannene Ackerman of Witco Corp. Ingredients: 1 2 3 4 5 6 7 8 9 10 587.5 cm3 gluten 4.9 cm3 NaHCO3 4.9 cm3 refined halite 176.25 cm3 partially hydrogenated tallow triglyceride 177.45 cm3 crystalline C12H22O11 177.45 cm3 unrefined C12H22O11 4.9 cm3 methyl ether of protocatechuic aldehyde Two calcium carbonate-encapsulated avian albumen-coated protein 473.2 cm3 theobroma cacao 236.6 cm3 de-encapsulated legume meats (sieve size #10) To a 2-L jacketed round reactor vessel (reactor #1) with an overall heat-transfer coefficient of about 100 Btu/F-ft2-hr add one, two, and three with constant agitation. In a second 2-L reactor vessel with a radial flow impeller operating at 100 rpm add four, five, six, and seven until the mixture is homogeneous. To reactor #2 add eight followed by three equal portions of the homogeneous mixture in reactor #1. Additionally, add nine and ten slowly with constant agitation. Care must be taken at this point in the reaction to control any temperature rise that may be the result of an exothermic reaction. Using a screw extrude attached to a #4 nodulizer place the mixture piece-meal on a 316SS sheet (300 x 600 mm). Heat in a 460K oven for a period of time that is in agreement with Frank & Johnston's first order rate expression (see JACOS, 21, 55), or until golden brown. Once the reaction is complete, place the sheet on a 25ºC heat-transfer table allowing the product to come to equilibrium. Conversion Factors 1 teaspoon = 5cm3 235 cm3 = 1 cup ºC = 9/5ºF +32 To Receive Credit: You must have a signed note from your parent/guardian that indicates that you made the cookies –you can even bring in a sample to your friendly Chemistry Teacher. -6- Name PROBLEMS: Use dimensional analysis to set up the problem. Please show your work! 1. Show your work here for how much of each item you need to measure out at home: 2. How many cookies did you made from this recipe? 3. If you only have 100cm3 of unrefined C12H22O11, how much gluten will you need? 4. You have decided with a group of friends to make these cookies for a fund raiser. It is your job to make 1000 cookies. How many calcium carbonate-encapsulated avian albumen-coated protein will you need to buy? 5. Adjust the recipe for 3 calcium carbonate-encapsulated avian albumen-coated protein and determine how much of each reactant you need in the recipe. -7- Name STOICHIOMETRY LAB—Simple Weight Loss A balanced equation indicates the proportions between reactants and products. More specifically, the coefficients in the equation indicate the mole ratios between the chemical substances. Thus, it is possible to determine how much product will be produced from a given amount of reactant. This predicted amount can then be compared with the actual amount produced to determine the percent yield of the reaction. In this experiment, you will investigate two reactions: 1. Copper and aqueous silver nitrate yield silver and aqueous copper(II) nitrate. 2. Sodium bicarbonate and aqueous sulfuric acid produce aqueous sodium sulfate, water, and carbon dioxide gas. SAFETY 2M sulfuric acid can cause burns. Avoid skin and eye contact. Rinse spills with plenty of water. PROCEDURE REACTION 1 1. Measure and record the mass of a copper wire (~20cm long). 2. Coil the wire to fit inside the test tube and insert. Cover with 15 mL of 0.1M AgNO3. Record the exact volume you used. 3. Observe the formation of silver crystals. After about 20 minutes, remove the wire and rinse it with distilled water. Record the mass of the wire. REACTION 2 4. Obtain a beral pipet containing 2M H2SO4. 5. Obtain a clean, dry modified jumbo pipet. Measure and record its mass. Place approximately 0.30 g (see sample) of NaHCO3 into the modified jumbo pipet using the plastic funnel as shown in Figure 1. Find the combined mass of the jumbo pipet and sodium bicarbonate and record. 6. Determine the exact mass of sodium bicarbonate by subtraction. This mass must be between 0.20 and 0.40 g. If your mass is not within this range, add or remove some solid until your mass falls within the desired limits. Record the mass of sodium bicarbonate in a data table. 7. Insert the beral pipet containing sulfuric acid into the jumbo pipet as shown in Figure 2. Measure and record the initial mass of this dual-pipet unit. 8. SLOWLY, drop by drop, release the sulfuric acid to generate carbon dioxide gas. Continue releasing the acid in this manner until gas production ceases. -8- Name Measure and record the final mass of the dual-pipet unit 9. Return the beral pipet with the remainder of the sulfuric acid to the chemicals table. Rinse the contents of the jumbo pipet down the drain with water. Allow the clean jumbo pipet to drain upside-down and clean up your lab station. DATA Construct a data table for each reaction to display your laboratory measurements. Make sure that each value is clearly labeled. ANALYSIS REACTION 1 1. Write a balanced equation for the reaction. 2. Calculate the actual mass of copper consumed (“actual yield”). 3. Using the balanced equation, calculate the mass of copper theoretically required to react with the volume of 0.1M AgNO3 that you used (“theoretical yield”). REACTION 2 4. Write a balanced equation for the reaction. 5. Calculate the actual mass of carbon dioxide produced (“actual yield”). 6. Using the balanced equation, calculate the mass of carbon dioxide that should be produced from the mass of sodium bicarbonate that you used (“theoretical yield”). CONCLUSIONS Calculate the percent yield of the copper in REACTION 1 and of the carbon dioxide in REACTION 2 using the equation below (show your work). % yield = experimental yield theoretical yield 100 A perfect percent yield would be 100%. For each reaction, comment on your degree of accuracy and suggest possible sources of measurement error. How could these errors be reduced in the future? -9- Name Chemistry Limiting Reactant Lab Introduction A limiting reactants is defined as one of the reactants in a chemical reaction that will be used up first. The purpose of this lab is to determine the amount of precipitate that will be produced when a given amount of barium chloride and sodium carbonate are mixed. Once you have massed the barium chloride and the sodium carbonate you will need to do each of the following before you proceed with the rest of the experiment. Write the balanced chemical reaction noting the states of matter for all substances. (See solubility chart to determine which substance precipitates.) Determine which reagent, barium chloride or sodium carbonate, is limiting. Predict the amount of the precipitate that will be produced. Once you have done these three things, show them to your instructor. Then you may begin the experiment. Procedure 1.Label and mass a test tube. The test tube must be completely dry 2.Obtain about 0.30 grams of each reagent (It doesn’t matter how much you get just as long as you know exactly how much you obtain), and determine both which reagent is limiting and how much precipitate you will discover. 3.Dissolve the barium chloride into 3 mL of deionized water by carefull flicking the test tube (Your instructor will show you how to do this. Dissolve the sodium carbonate into 3-mL of deionized water. 4.Pour the sodium carbonate solution into the test tube with barium chloride in it. Take care to get all of the sodium carbonate into the barium chloride test tube. 5.Remove the stopper and then place your sample into a centrifuge and spin out the precipitate. (Caution should be used in using this device. Your teacher will instruct you on proper use of a centrifuge) 6.Decant, or pour off, the liquid (supernatant) above the precipitate. Be careful not to allow any of the precipitate to be poured out. 7.Add about 10-mL of deionized water to your precipitate and spin it again. Decant again and repeat this step two more times for a total of four centrifuges 8.Set your labeled test tube into a drying oven overnight. 9.Weigh your test tube and determine the mass of the precipitate that you have. Compare this amount to what you expected to get from your calculations. Calculations - 10 - Name Show all calculations needed to determine the expected amount of precipitate required to do the experiment. This should include the balanced chemical reaction and all appropriate stoichiometric calculations. Questions 1.Why did you have to mass the test tube prior to beginning the experiment? 2.Why did you need to add water to the solid barium chloride and solid sodium carbonate to cause the reaction to occur? 3.Comment on sources of error. 4.What was your percentage of error? 5.Draw a picture of the two test tubes prior to adding the two chemicals. What had happened to the barium chloride? What happened to the sodium carbonate. 6.Now draw a picture of the test tube once you have mixed the two chemicals. Where are all of the chemicals now? Label this in your diagram. - 11 - Name Limiting Reactant Exploration Lab: How much Carbon Dioxide? Introduction: In this lab you will do a cool reaction, make some measurements, make a graph, and then write down some observations. The reaction that you will do is the reaction between vinegar and baking soda. In this reaction, carbon dioxide, CO2 will be produced. Chemists use chemical symbols to show the reaction. The reaction is: CH3COOH (aq) Vinegar + NaHCO3 Baking Soda H2O Water + Materials: Apparatus as pictured below Vinegar Baking Soda To simplify: Here is a picture of what you will need: Procedure: Follow this procedure as closely as possible. 1. place 0.25 g into a paper towel 2. Get the appropriate amount of vinegar into the flask 3. Set-up the apparatus—and mix. 4. Record the amount of CO2 collected - 12 - CO2 + Carbon Dioxide NaCH3COO Sodium Acetate Name Data Fill out the following data table: Amount of vinegar 1 1 mL Amount of baking soda 0.25g 2 2 mL 0.25g 3 3 mL 0.25g 4 4 mL 0.25g 5 5 mL 0.25g 6 6 mL 0.25g Vol CO2 Questions 1. Describe in detail what occurred (your observations) when the vinegar was mixed with the baking soda. Some descriptive words that you should probably use are, but not including (gas given off, fizzing, foaming, balloon expanding) 2. Describe the pattern of how much carbon dioxide, CO2 was formed as you added more and more vinegar. Relate this to the graph. 3. For each trial: explain which substance was the limiting and excess reagent. Explain how you were able to determine this. 4. You should have noticed that as you increased the amount of vinegar eventually you got the same amount of carbon dioxide, CO2. Explain why that occurred. - 13 - Name - 14 - Name Stoichiometry Worksheet A 1. Carbon disulfide is an important industrial solvent. It is prepared by the reaction of coke with sulfur dioxide: 5C(s) + 2SO2(g) -----> CS2(s) + 4CO(g) a. How many moles of CS2 form when 6.3 mol of C reacts? b. How many moles of carbon are needed to react with 7.24 moles of SO2 2. Silver can be made according to the following equation: AgNO3+ Ca Ca(NO3)2 + Ag Balance the equation If 35.3 moles of silver nitrate are reacted how many moles of silver are produced? 3. Barium oxide reacts with carbon dioxide to make Barium carbonate: BaO + CO2 BaCO3 Balance the equation If 23.4 moles of barium oxide react, how many liters of CO2 are required at STP? 4. Car batteries are called lead storage batteries because of their use of large quantities of lead. These batteries utilize the following equation. Pb + PbO2 +2H+ + 2HSO4- 2PbSO4 + 2 H2O If 34.3-g of PbO2 react how many grams of water will be formed? Assuming the same mass of PbO2, how many grams of PbSO4 will be formed? - 15 - Name 5. Ammonia, (NH3) is produced by reacting its elements with each other according to the following equation: N2 + H2 NH3 Balance the equation. If 34.3-L of nitrogen is reacted with hydrogen, how many liters at STP of ammonia will be formed? 6. 32.5-g of ZnSO4 reacts to form how many grams of BaSO4 according to the following equation. Don’t forget to balance the equation. ZnSO4 + BaCl2 BaSO4 + ZnCl2 7. When sodium metal is added to water the resulting gas, Hydrogen can often explode. How many Liters of hydrogen gas is produced when 41.2-g of sodium is dropped into water. Again, you must balance the equation in order to solve the problem. Na + HOH NaOH + H2 8. Propane is a gas used often for backyard grills. How many Liters of CO2 is produced when 54.9-L of propane (C3H8) is burned according to the following equation. Again, you must balance the equation in order to solve the problem. C3H8 + O2 CO2 + H2O - 16 - Name Stoichiometry WS B 1. How many moles of Carbon dioxide is formed when 44-mol of CH4 is burned? 2. 43.5-grams of barium sulfate is formed from the reaction of barium nitrate and sodium sulfate. How many moles of sodium sulfate reacted? 3. 32.3-L of O2 is formed when KClO3 is decomposed. How many moles of KClO3 reacted initially? __KClO3 __KCl + __O2 4. 22.8-g of NaOH is reacted with hydrochloric acid. How many grams of water is formed? 5. 32.5-grams of iron III chloride reacts with silver nitrate. How many grams of silver chloride are formed? - 17 - Name 6. 43.5-grams of copper II sulfate is reacted with barium nitrate. How many grams of precipitate are formed? 7. How many liters of hydrogen gas is formed when 13.5-grams of calcium reacts with sulfuric acid (H2SO4)? 8. Calculate the mass of silver needed to react with chlorine to produce 84 g of silver chloride. 9. A volume of 7.5 L of hydrogen gas was produced from the single replacement reaction of zinc and nitric acid (HNO3). Calculate the mass of zinc needed for this reaction. 10. How many molecules of chlorine are needed to react with 5.6 g of iron to form iron III chloride? - 18 - Name 11. What mass of ammonia, NH3, is necessary to react with 2.1 x 1024 molecules of oxygen when ammonia (NH3) reacts with oxygen to form water and nitrogen dioxide? 12. Calculate the volume of carbon dioxide produced when 250 g of pentane, C5H12, burn. Assume the carbon dioxide is cooled to STP. 13. Silver Nitrate reacts with sodium chloride to make the silver chloride and sodium nitrate. When 2.53 grams of silver nitrate is reacted. How many grams of silver chloride are formed? 14. Calcium Carbonate decomposes into calcium oxide and a common gas. When 45.5 grams of calcium oxide is formed how many liters of gas is also formed from this reaction. 15. When 3.25 g of copper II nitrate reacts with ammonium hydroxide. How many grams of the precipitate will form. - 19 - Name Stoichiometry WS C: Limiting Reactants BOX ALL ANSWERS!! 1. When 114.0 g of iron and 292.7 g of chlorine gas reacts, iron(III) chloride is formed. a. Write a balanced equation b. How many grams of Iron (III) chloride is formed c. What is the limiting reactant? d. How much excess reagent is left over at the end of the experiment? 2. 20 L of oxygen react with 1.0L of methyl alcohol, CH3OH a. Write a balanced equation b How many liters of water will be formed at STP? c. What is the limiting reactant? d. How much excess reagent is left over at the end of the experiment? - 20 - Name 3. 25 g of hydrazine, N2H4(l), and 66 g of hydrogen peroxide, H2O2(l), react to produce nitrogen gas and water. a. Write a balanced equation b. How many grams of nitrogen are produced? c. What is the limiting reactant? d. How much excess reagent is left over at the end of the experiment? 4. 22.5 grams of lithium reacts with 33.5 grams of aqueous aluminum sulfate. This is a single replacement reaction. a. Write a balanced equation. b. How many grams of lithium sulfate will be formed? c. What is the limiting reactant? d. How much excess reagent is left over at the end of the experiment? - 21 - Name 5. 33.6 grams of sulfur dioxide reacts with 55.3 grams of water to form sulfurous acid (H2SO3). a. Write a balanced equation. b. How many grams of sulfurous acid will be formed? c. What is the limiting reactant? d. How much excess reagent is left over at the end of the experiment? 6. 77 g of potassium iodide react with 32 g of lead II nitrate reacts to form a yellow precipitate. a. Write a balanced equation and identify the precipitate b. How many grams of the precipitate will be formed? c. What is the limiting reactant? d. How much excess reagent is left over at the end of the experiment? - 22 - Name 7. In the following equation: NH3 + O2 H2O + NO2 a. Balance the equation c. If you react 22 L of NH3 with 95 L of air (Which is 20% oxygen), how many liters of NO2, will be produced? c. What is the limiting reagent? d. How much excess reagent will remain? - 23 - Name Stoichiometry WS D: Percent Yield 1. 15.5-g of NH4Cl reacts with an excess of AgNO3. In the reaction 35.5-g AgCl is produced. NH4NO3 is the other product. What is the percent yield? 2. Potassium Chlorate decomposes according to the following reaction. 2KClO3 2KCl +3 O2 In an experiment 32.5-g of KClO3 is decomposed and 15.2-g of KCl is formed. What is the percent yield? 3. Nitrogen gas reacts with hydrogen gas to make ammonia (NH3). 15.5-L of N2 reacts at STP to make 30-L of ammonia. What is the percent yield? 4 What is the percent yield of oxygen gas if 54L of O2 can be obtained from the thermal decomposition of 500.0 g of potassium chlorate? KClO3 KCl + O2 - 24 - Name 5. It is desired to prepare 100.0g of silicon tetrafluoride by adding hydrogen fluoride to silicon dioxide. The percent yield of this process is 75%. Ho much HF do you need to react? The other product is water. 6. When black gunpowder explodes, potassium nitrate, carbon, and sulfur react with each other to form nitrogen, carbon dioxide, and potassium sulfide. If the original mixture contains 50.0 g of potassium nitrate, if the total volume of the gases is 20L, then what is the percent yield for this process? 7. Very hot zinc will react with steam to form zinc oxide and hydrogen. 5.4L of H2 was used to use up 20.0 g of zinc completely? What is the percent yield of this process? - 25 - Name Worksheet E Molar Mass Worksheet Name _________________ 1. 2.35g of metal with a charge of +2 reacts with hydrochloric acid to produce 0.598 L of gas at STP. What metal do you have? M + HCl MCl2 + H2 2. (NH4)3PO4 reacts with 0.0345 g of metal sulfate (M2(SO4)3) to produce 0.0399 g of (NH4)2SO4. Balance the equation. What is the molar mass of the metal? What is the metal? __M2(SO4)3 + __(NH4)3PO4 __(NH4)2SO4 + __MPO4 3. 3.45g of a metal hydroxide with charge + 1 reacts with excess Iron III Chloride to make 0.82g of Iron III hydroxide. What is the identity of the metal hydroxide? 4. 30.2 L of oxygen is produced at STP when 135.9 g of metal chlorate of charge +3 decomposes into oxygen and the metal chloride. What is the identity of the metal chlorate? - 26 - Name Stoichiometry WS F: Mixed Problems=Review 1. How many grams of water are formed when 12.5-g of hydrogen reacts with oxygen? 2. How many liters of carbon dioxide are formed when 12.3-g of sodium carbonate reacts with 2.0-L of hydrogen chloride. The reaction is printed below: Na2CO3 + HCl NaCl + H2O + CO2 3. How many grams of precipitate are formed when 24.3-g of zinc nitrate reacts with 20.5g of sodium phosphate? 4. How many liters of oxygen are produced when 3.25-g of KClO3 decomposes into KCl and O2? - 27 - Name 5. When 2.25-g of sodium chloride reacts with excess silver nitrate, 3.45-g of precipitate is formed. What is the percent yield of the precipitate? 6. 4.35-g of C5H12 reacts with 4.0-L of O2. a. How many liters of CO2 are formed? b. How much excess reactant remains? 7. 3.0-g of zinc reacts with silver nitrate to form how many grams of zinc nitrate? 8. 8.2-mol of barium carbonate decomposes into how many moles of barium oxide. The other product is carbon dioxide. - 28 - Name 9. 4.5-g of sodium hydroxide reacts with 2.0-g of sulfuric acid (H2SO4). How many grams of water are formed? 10. 8.0-L of butane (C4H10) reacts with oxygen to make 50-g of carbon dioxide. What is the percent yield? 11. 8.5-L of hydrogen reacts with 5.4-L of nitrogen to make… a. how many liters of ammonia (NH3)? b. How many liters of excess reactant remains? 12.A 2.25-g sample of aluminum sulfate reacts with 3.25-g of sodium phosphate to make 1.0-g of precipitate. What is the percent yield? - 29 - Name Stoichiometry Worksheet 1 KEY 1. Carbon disulfide is an important industrial solvent. It is prepared by the reaction of coke with sulfur dioxide: 5C(s) + 2SO2(g) -----> CS2(s) + 4CO(g) How many moles of CS2 form when 6.3 mol of C reacts? How many moles of carbon are needed to react with 7.24 moles of SO2 6.3molC 1molCS2 x 1.26molCS2 1 5molC 7.2molSO2 5molC x 18molC 1 2molSO2 2. Silver can be made according to the following equation: 2AgNO3+ Ca Ca(NO3)2 + 2Ag 35.3g ?g Balance the equation If 35.3 moles of silver nitrate are reacted how many moles of silver are produced? 5.3gAgNO3 2molAg x 35.3molAg 1 2molAgNO3 3. Barium oxide reacts with carbon dioxide to make Barium carbonate: BaO + CO2 - BaCO3 (Balanced) 23.4mol L? Balance the equation If 23.4 moles of barium oxide react, how many liters of CO2 are required at STP? 23.4molBaO 1molCO2 22.4 LCO2 x x 524 LCO2 1 1molBaO 1molCO2 - 30 - Name 4. Car batteries are called lead storage batteries because of their use of large quantities of lead. These batteries utilize the following equation. Pb + PbO2 +2H+ + 2HSO4- 2PbSO4 + 2 H2O 34.3g g? If 34.3-g of PbO2 react how many grams of water will be formed? Assuming the same mass of PbO2, how many grams of PbSO4 will be formed? 34.3gPbO2 1molPbO2 2molH 2O 18gH 2O x x x 1 239gPbO2 1molPbO2 1molH 2O 5.16gH 2O 34.3gPbO2 1molPbO2 2molPbSO4 303gPbSO4 x x x 1 239gPbO2 1molPbO2 1molPbSO4 87.0gPbSO4 5. Ammonia, (NH3) is produced by reacting its elements with each other according to the following equation: N2 + 3H2 2NH3 34.3L L? Balance the equation. If 34.3-L of nitrogen is reacted with hydrogen, how many liters at STP of ammonia will be formed? - 31 - Name 34.3LN 2 2LNH3 x 68.6LNH3 1 molN 2 6. 32.5-g of ZnSO4 reacts to form how many grams of BaSO4 according to the following equation. Don’t forget to balance the equation. ZnSO4 + BaCl2 BaSO4 + ZnCl2 bal 32.5g g? 32.5gZnSO4 1molZnSO4 1molBaSO4 233gBaSO4 x x x 1 161gZnSO4 1molZnSO4 1molBaSO4 47.0gBaSO4 7. When sodium metal is added to water the resulting gas, Hydrogen can often explode. How many Liters of hydrogen gas is produced when 41.2-g of sodium is dropped into water. Again, you must balance the equation in order to solve the problem. 2Na + 2HOH 2NaOH + H2 41.2g L? 41.2gNa 1molNa 1molH 2 22.4LH2 x x x 1 23gNa 2molNa 1molH 2 20.1LH2 8. Propane is a gas used often for backyard grills. How many Liters of CO2 is produced when 54.9-L of propane (C3H8) is burned according to the following equation. Again, you must balance the equation in order to solve the problem. C3H8 + 5O2 3CO2 + 4H2O 54.9L L? 54.9LC3 H8 3LCO2 x 165LCO2 1 1molC3 H8 - 32 - Name Stoichiometry WS B Name Period 1. How many moles of Carbon dioxide is formed when 44-mol of CH4 is burned? CH 4 2O2 CO2 2 H 2O 44mol ?mol +4 44mol CH 4 1molCO2 x 44molCO2 1 1molCH 4 2. How many moles of calcium phosphate is formed when 32.5-mols of calcium nitrate reacts with sodium phosphate? 3Ca(NO3 )2 2Na3 PO4 Ca3 (PO4 )2 6NaNO3 32.5mol ?mol 32.5mol Ca(NO3 )2 1molCa3 (PO4 ) 2 x 10.8molCa3 (PO4 )2 1 3molCa(NO3 )2 3. 43.5-grams of barium sulfate is formed from the reaction of barium nitrate and sodium sulfate. How many moles of sodium sulfate reacted? Ba(NO3 )2 Na2 SO4 BaSO4 2NaNO3 ?mol 43.5g 43.5gBaSO4 1molBaSO4 1molNa2 SO4 x x 0.187molNa2 SO4 1 233gBaSO4 1molBaSO4 4. 32.3-L of O2 is formed when KClO3 is decomposed. How many moles of KClO3 reacted initially? 2KClO3 2KCl 3O2 ?mol 32.3L 32.3LO2 1molO2 2molKClO3 x x 0.961molKClO3 1 22.4LO2 3molO2 - 33 - Name 5. 2.5-mol of water is made from its elements. How many particles of hydrogen reacted? 2H 2 O2 2H 2O ?part 2.5mol 2.5molH 2O 2molH 2 6.02x10 23 particlesH 2 x x 1 2molH 2O 1molH 2 1.5x10 24 particlesH 2 6. 22.8-g of NaOH is reacted with hydrochloric acid. How many grams of water is formed? NaOH HCl HOH NaCl 22.8g ?g 22.8gNaOH 1molNaOH 1molHOH 18gHOH x x x 1 40gNaOH 1molNaOH 1molHOH 10.3gHOH 7. 32.5-grams of iron III chloride reacts with silver nitrate. How many grams of silver chloride are formed? FeCl3 3AgNO3 3AgCl Fe(NO3 ) 3 32.5g ?g 32.5gFeCl3 1molFeCl3 3molAgCl 143.5gAgCl x x x 1 162.5gFeCl3 1molFeCl3 1molAgCl 86.1gAgCl 8. 34.5-grams of Lithium reacts with Chromium III chloride. How many grams of lithium is formed? chloride 3Li CrCl3 3LiCl Cr 34.5g ?g 34.5gLi 1molLi 3molLiCl 42.5gLiCl x x x 209gLiCl 1 7gLi 3molLi 1molLiCl - 34 - Name 9. 43.5-grams of copper II sulfate is reacted with barium nitrate. How many grams of precipitate are formed? CuSO4 Ba ( NO3 ) 2 BaSO4 ( s ) Cu( NO3 ) 2 ( aq) 43.5 g g? 43.5gCuSO4 1molCuSO4 1molBaSO 4 233 gBaSO4 x x x 1 159.5 gCuSO4 1molCuSO4 1molBaSO4 63.5 gBaSO4 10 How many liters of hydrogen gas is formed when 13.5-grams of calcium reacts with sulfuric acid? Ca H 2 SO4 CaSO4 H 2 13.5g ?L 13.5gCa 1molCa 1molH 2 22.4LH 2 x x x 1 40gCa 1molCa 1molH 2 7.6LH 2 11. 45.6-L of H2 is formed when zinc is reacted with nitric acid. How many grams of zinc reacted? Zn 2 HNO3 Zn( NO3 ) 2 H 2 ?g 45.6L 45.6LH 2 1molH 2 1molZn 65 gZn x x x 1 22.4 LH 2 1molH 2 1molZn 132 gZn - 35 - Name 12. 14.5-g of cesium explosively reacts with water to form hydrogen and cesium hydroxide. How many molecules of hydrogen were formed? 2Cs 2 H 2O 2CsOH H 2 14.5 g ?molec 14.5gCs 1molCs 1molH 2 6.02 x1023 molecH 2 x x x 1 133gCs 2molCs 1molH 2 3.28 x1022 molecH 2 13. Calculate the mass of silver needed to react with chlorine to produce 84 g of silver chloride. 2Ag + Cl2 2AgCl ? 84g 2Ag Cl2 2AgCl 84gAgCl 1molAgCl 2molAg 108gAg x x x 63.2gAg 1 143.5gAgCl 2molAgCl 1molAg 14. A volume of 7.5 L of hydrogen gas was produced from the single replacement reaction of zinc and nitric acid (HNO3). Calculate the mass of zinc needed for this reaction. Zn + 2HCl ZnCl2 + H2 g? 7.5L 7.5LH 2 1molH 2 1molZn 65 gZn x x x 1 22.4 LH 2 1molH 2 1molZn 21.8 gZn 15. How many molecules of chlorine are needed to react with 5.6 g of iron to form iron III chloride? 3Cl2 + 2Fe 2FeCl3 Molec? 5.6g 5.6gFe 1molFe 3molCl2 6.02x10 23 molecCl2 x x x 1 56gFe 2molFe 1molCl2 9.03x10 22 molecCl2 16. What mass of ammonia, NH3, is necessary to react with 2.1 x 1024 molecules of oxygen when ammonia (NH3) reacts with oxygen to form water and nitrogen dioxide? - 36 - Name 4NH3 g? + 7O2 2.1 x 1024 molec 4NO2 + 6H2O 2.1x10 24 molecO2 1molO2 4molNH3 17gNH3 x x x 23 1 6.02x10 molecO2 7molO2 1molNH3 33.9gNH3 17. Calculate the volume of carbon dioxide produced when 250 g of pentane, C5H12, burn. Assume the carbon dioxide is cooled to STP. C5H12 + 8O2 5CO2 + 6H2O 250g ?L 250gC5 H12 1molC5 H12 5molCO2 22.4LCO2 x x x 1 72gC5 H12 1molC5 H12 1molCO2 389LCO2 18. Nitrogen gas reacts with oxygen to form dinitrogen trioxide. How many molecules of oxygen are needed to make 5.5 L of N2O3 at STP? 2N2 + 3O2 2N2O3 molec? 5.5L 23 2 3 2 3 2 5.5LN O 1molN O 3molO 6.02 x10 molecO2 x x x 1 22.4 LN 2O3 2molN 2O3 1molO2 2.2 x10 23 moleculesO2 19. Silver Nitrate reacts with sodium chloride to make the silver chloride and sodium nitrate. When 2.53 grams of silver nitrate is reacted. How many grams of silver chloride are formed? AgNO3 + NaCl AgCl + NaNO3 2.53g ?g 2.53gAgNO3 1molAgNO3 1molAgCl 143.5gAgCl x x x 1 170gAgNO3 1molAgNO3 1molAgCl 2.14gAgCl - 37 - Name 20. Methane (CH4) is burned in air. When 50.6 L of methane is burned how many grams of carbon dioxide will be formed? CH4 + 2O2 CO2 + 2H2O 50.6L ?g 50.6LCH4 1molCH4 1molCO2 44gCO2 x x x 1 22.4LCH4 1molCH4 1molCO2 99.4gCO2 21. Calcium Carbonate decomposes into calcium oxide and a common gas. When 45.5 grams of calcium oxide is formed how many liters of gas is also formed from this reaction. CaCO3 CaO + CO2 45.5g ?L 45.5gCaO 1molCaO 1molCO2 22.4LCO2 x x x 1 56gCaO 1molCaO 1molCO2 18.2LCO2 22. When 3.25 g of copper II nitrate reacts with ammonium hydroxide. How many grams of the precipitate will form. Cu(NO3)2 + 2NH4OH Cu(OH)2 (s) + 2NH4NO3 (aq) 3.25g ?g=ppt 3.25gCu(NO3 ) 2 1molCu(NO3 ) 2 1molCu(OH) 2 97.5gCu(OH) 2 x x x 1 187.5gCu(NO3 ) 2 1molCu(NO3 ) 2 1molCu(OH) 2 1.69gCu(OH) 2 +88 - 38 - Name Limiting Reactant Worksheet Do all work on a separate sheet of paper and BOX ALL ANSWERS!! 1. When 114.0 g of iron and 292.7 g of chlorine gas reacts, iron(III) chloride is formed. a. Write a balanced equation b. What is the limiting reactant? c. How many grams of Iron (III) chloride is formed a. How much excess reagent is left over at the end of the experiment? 2Fe 3Cl2 2FeCl3 114g 292.7g ?g 114gFe 1molFe 2molFeCl3 162.5gFeCl3 x x x 331gFeCl3 1 56gFe 2molFe 1molFeCl3 292.7gCl 2 1molCl 2 2molFeCl3 162.5gFeCl3 x x x 447gFeCl3 1 71gCl 2 3molCl 2 1molFeCl3 Fe is the LR because it yielded the smallest answer 114gFe 1molFe 3molCl2 71gCl2 x x x 217gCl2 used up 1 56gFe 2molFe 1molCl2 292.7 217g 75.9gCl2 left 2. 20 L of oxygen react with 1.0L of methyl alcohol, CH3OH a. Write a balanced equation b. What is the limiting reactant? c How many liters of water will be formed at STP? d. How much excess reagent will be left over? 2CH 3OH 3O2 2CO2 4H2 O 1.0L 20L ?L 1.0LCH3 OH 4LH 2 O x 2LH2 O 1 2LCH3 OH 20LO2 4LH2 O x 27LH2 O 1 3LO2 CH3OH is the LR because it yielded the smallest answer 1.0LCH3 OH 3LO2 x 1.5LO2 1 2LCH3 OH 20L 1.5L 18.5LO2 Left - 39 - Name 3. 25 g of hydrazine, N2H4(l) and 66 g of hydrogen peroxide, H2O2 (l) react exothermically to produce nitrogen gas and water. a. Write a balanced equation b. What is the limiting reactant? c. How many grams of nitrogen are produced? d. How much excess reagent is left over? N2 H4 2H2 O2 N2 4H2 O 25g 66g g? 25gN2 H4 1molN2 H4 1molN 2 28gN2 x x x 22gN 2 1 32gN2 H4 1molN2 H4 1molN 2 66gH2 O2 1molH 2 O2 1molN2 28gN2 x x x 27gN2 1 34gH 2O2 2molH2 O2 1molN2 N2 H4 is the LR because it yielded the smallest answer 25gN2 H4 1molN2 H4 2molH2 O2 34gH2 O2 x x x 53gH2 O2 1 32gN2 H4 1molN2 H4 1molH 2 O2 66g 53g 13gH2 O2 leftover 4. 22.5 grams of lithium reacts with a 33.5 grams of aqueous aluminum sulfate according to a single replacement reaction. a. Write a balanced equation. b. What is the limiting reactant? c. How many grams of lithium sulfate will be formed? d. How much excess reagent will remain? 6Li Al2 (SO4 )3 3Li2 SO4 2Al 22.5g 33.5 g? 22.5gLi 1molLi 3molLi2 SO4 110gLi2 SO4 x x x 177gLi2 SO4 1 7g 6molLi 1molLi2 SO4 33.5gAl2 (SO4 ) 3 1molAl 2 (SO4 )3 3molLi2 SO4 110gLi2 SO4 x x x 32gLi2 SO4 1 342gAl 2 (SO4 )3 1molAl2 (SO4 )3 1molLi2 SO4 Al2 (SO4 ) 3 is the LR since it yields the smaller value 33.5gAl2 (SO4 ) 3 1molAl 2 (SO4 )3 6molLi 7gLi x x x 4.1gLi 1 342gAl 2 (SO4 )3 1molAl2 (SO4 )3 1molLi 22g 4.1g 18gLiLeftover - 40 - Name 5. 33.6 grams of sulfur dioxide reacts with 55.3 grams of water to form sulfurous acid. a. Write a balanced equation. b. What is the limiting reactant? c. How many grams of sulfurous acid will be formed? d. How much excess reagent will remain? SO2 H2 O H2 SO3 33.6g 55.3g g? 33.6gSO2 1molSO2 1molH2 SO3 82gH 2 SO3 x x x 43gH2 SO3 1 64gSO2 1molSO2 1molH 2 SO3 55.3gH2 O 1molH2 O 1molH 2 SO3 82gH2 SO3 x x x 252gH2 SO3 1 18gH2O 1molH 2 O 1molH2 SO3 SO2 is the LR since it yields the smaller value 33.6gSO2 1molSO2 1molH2 O 18gH 2 O x x x 9.5gH2 O 1 64gSO2 1molSO2 1molH 2 O 55.3g 9.5g 45.8gH2 OLeftover 6. 77 g of potassium iodide react with 32 g of Lead II nitrate reacts to form a yellow precipitate. a. Write a balanced equation and identify the precipitate b. What is the limiting reactant? c. How many grams of the precipitate will be formed? d. How much excess reagent will remain? 2KI Pb(NO3 ) 2 PbI2 2KNO3 77g 32g g? 77gKI 1molKI 1molPbI2 461gPbI2 x x x 107gPbI2 1 166gKI 2molKI 1molPbI2 32gPb(NO3 )2 1molPb(NO3 )2 1molPbI 2 461gPbI2 x x x 45gPbI2 1 331gPb(NO3 )2 1molPb(NO3 ) 2 1molPbI 2 Pb(NO3 ) 2 is the LR since it yields the smaller value 32gPb(NO3 )2 1molPb(NO3 )2 2molKI 166gKI x x x 32gKI 1 331gPb(NO3 )2 1molPb(NO3 ) 2 1molKI 77g 32g 45gKILeftover - 41 - Name *7. In the following equation: NH3 + O2 ---> H2O + NO2, a. Balance the equation b. What is the limiting reactant? c. If you react 22 L of NH3 with 95 L of air (Which is 20% oxygen), how many liters of NO2, will be produced? d. How much excess reagent will remain? 4NH3 7O2 6H 2O 4NO2 22L 19L L? I got 19L of air by mulitplying 95L of air by 20% 22LNH3 4LNO2 x 22LNO2 1 4LNH3 19LO2 4LNO2 x 11LNO2 1 7LO2 O2 is the LR since it yields the smaller value 19LO2 4LNH3 x 11LNH3 1 7LO2 22L 11L 11LNH3 Leftover - 42 - Name WS D: Percent Yield Worksheet 1. 15.5-g of NH4Cl reacts with an excess of AgNO3. In the reaction 35.5-g AgCl is produced. NH4NO3 is the other product. What is the percent yield? NH4Cl + AgNO3 AgCl + NH4NO3 15.5g 35.5g 15.5gNH4 Cl 1molNH4 Cl 1molAgCl 143.5gAgCl x x x 1 53.5gNH4 Cl 1molNH4 Cl 1molAgCl 41.57gAgCl 35.5g % x100 85.3% 41.57g 2. Potassium Chlorate decomposes according to the following reaction. 2KClO3 2KCl +3 O2 In an experiment 32.5-g of KClO3 is decomposed and 15.2-g of KCl is formed. What is the percent yield? 2KClO3 2KCl + 3O2 32.5g 15.2g 32.5gKClO3 1molKClO3 2molKCl 74.5gKCl x x x 1 122.5gKClO3 2molKClO3 1molKCl 19.7gKCl 15.2g % x100 76.9% 19.7g - 43 - Name 3. Nitrogen gas reacts with hydrogen gas to make ammonia (NH3). 15.5-L of N2 reacts at STP to make 30-L of ammonia. What is the percent yield? N2 15.5L + 3H2 2NH3 30L 15.5LN 2 2LNH3 x 31LNH3 1 2LN 2 30L % x100 97% 31L 4. The Haber and Caude processes are methods by which ammonia (NH3) is synthesized from its elements (H2 and N2) What is the percent yield if 5.0-kg of ammonia (in Kilograms) is to be expected when 4000.0 L of nitrogen are used in these procedures? N2 3H 2 2NH3 4000L 5000g 4000LN 2 1molN 2 2molNH3 17gNH3 1kgNH3 x x x x 6.071kgNH3 1 22.4LN 2 1molN 2 1molNH3 1000gNH3 % 5.0kg x100 82.3% 6.07kg 5. What is the percent yield of oxygen gas if 54L of O2 can be obtained from the thermal decomposition of 500.0 g of potassium chlorate? 2KClO3 2KCl 3O2 500.0g 54L 500gKClO3 1molKClO3 3molO2 22.4LO2 x x x 137LO2 1 122.5gKClO3 2molKClO3 1molO2 % 54L x100 39.4% 137L - 44 - Name 6. It is desired to prepare 100.0g of silicon tetrafluoride by adding hydrogen fluoride to silicon dioxide. The percent yield of this process is 75%. Ho much HF do you need to react? 4 HF SiO2 SiF4 2 H 2 O ?L 100.0g(75% ) 100g x :: x 133gSiF4 75% 100% 133gSiF4 1molSiF4 4molHF 22.4 LHF x x x 114.6 LHF 1 104 gSiF4 1molSiF4 1molHF 7. When black gunpowder explodes, potassium nitrate, carbon, and sulfur react with each other to form nitrogen, carbon dioxide, and potassium sulfide. If the original mixture contains 50.0 g of potassium nitrate, if the total volume of the gases is 20L, what is the percent yield for this process? 2 KNO3 3C S N 2 3CO2 K 2 S 50g total vol of gases which are N 2 andCO2 50 gKNO3 1molKNO3 4mo lg ases 22.4 Lgases x x x 22.2 Lgases 1 101gKNO3 2molKNO3 1mo lg ases % 20 L x100 90.0% 22.2 L 8. Very hot zinc will react with steam to form zinc oxide and hydrogen. 5.4L of H2 was used to use up 20.0 g of zinc completely? What is the percent yield of this process? Zn H 2O ZnO H 2 20g ?L 20gZn 1molZn 1molH 2 22.4Lgases x x x 6.9LH 2 1 65gZn 1molZn 1molH 2 5.4L x100 78.3% 6.9L - 45 - Name WS E Molar Mass Worksheet 1. KEY Name _________________ 2.35g of metal with a charge of +2 reacts with hydrochloric acid to produce 0.598 L of gas at STP. What metal do you have? M 2 HCl H 2 MCl2 2.35 g............0.598 L grams 2.35 g MM mol mol ? 0.598 LMH 2 1molH 2 1molM x x 0.0267 molM 1 22.4 LH 2 1molH 2 grams 2.35 g 88 g / mol mol 0.0266mol Strontium 2. (NH4)3PO4 reacts with 0.0345 g of metal sulfate (M2(SO4)3) to produce 0.0399 g of (NH4)2SO4. Balance the equation. What is the molar mass of the metal? What is the metal? __M2(SO4)3 + 2(NH4)3PO4 3(NH4)2SO4 + 2MPO4 0.0345g 0.0456g MM g 0.0345 g :: FindMoles mol mol 0.0399 g ( NH 4 ) 2 SO4 1mol ( NH 4 ) 2 SO4 1molM 2 ( SO4 )3 x x 1.00757 x10 4 molM 2 ( SO4 )3 1 132 g ( NH 4 ) 2 SO4 4 3mol ( NH 4 ) 2 SO4 MM MM g 0.0345 g 0.0345 gM 2 ( SO4 )3 342 g / mol M 2 ( SO4 )3 mol mol 1.00757 x10 4 molM 2 ( SO4 )3 2 M (32 x3 16 x12) 342 M 27 g / mol Alu min um ::: mustHave 3Ch arg e( HasToBeAMe tal ) - 46 - Name 3. 3.45g of a metal hydroxide with charge + 1 reacts with excess Iron III Chloride to make 0.82g of Iron III hydroxide. What is the identity of the metal hydroxide? 3MOH FeCl3 Fe(OH ) 3 3MCl 3.45 g......................0.82 g grams 3.45 g mol mol ? 1 molFe (OH ) 3 2 0.82 gMOH 3molMOH x x 0.0230molMOH 1 107 gFe(OH ) 3 1molFe(OH ) 3 MM grams 3.45 g 150 g / mol mol 0.0230mol MOH 36 g / mol MM M 17 150 MM 133 Cs 4. 30.2L of oxygen is produced at STP when 135.9 g of metal chlorate of charge +3 decomposes into oxygen and the metal chloride. What is the identity of the metal chlorate? 2M (ClO3 ) 3 2MCl 9O2 135.9 g 30.2L 30.2O2 1molO2 2molM (ClO3 ) 3 x x 0.299molM (ClO3 ) 3 1 22.4 LO2 9molO2 MM 135.9 gM (ClO3 ) 3 grams 303g / mol mol 0.299molM (ClO3 ) 3 g M (ClO3 ) 3 454 mol M (35.5 x3 16 x9) 454 M 250 454 M 204 g / mol Tl - 47 - Name Mixed Stoichiometry Worksheet KEY 1. How many grams of water are formed when 12.5-g of hydrogen reacts with oxygen? 2H2 + O2 2H2O 12.5g ?g 12.5gH 2 1molH2 2molH 2O 18gH 2O x x x 1 2gH 2 2molH 2 1molH 2O 112.5gH 2O 2. How many liters of carbon dioxide are formed when 12.3-g of sodium carbonate reacts with 2.0-L of hydrogen chloride. The reaction is printed below: Na2CO3 + HCl NaCl + H2O + CO2 Na2CO3 + 2HCl 2NaCl + H2 O + CO2 12.3g 2.0L L? 12.3gNa2CO3 1molNa2CO3 1molCO2 22.4LCO2 x x x 1 106Na2CO3 1molNa2CO3 1molCO2 2.60LCO2 2.0LHCl 1LCO2 x 1.0LCO2 1 2LHCl 1.0LCO2 : Answer because it is the lowest 3. How many grams of precipitate are formed when 24.3-g of zinc nitratre reacts with 20.5-g of sodium phosphate? 3Zn(NO3)2 + 2Na3PO4 Zn3(PO4)2 + 6NaNO3 24.3g 20.5g ?g (ppt) 24.3gZn(NO3 ) 2 1molZn(NO3 ) 2 1molZn 3 (PO4 ) 2 385gZn3 (PO4 ) 2 x x x 1 189gZn(NO3 ) 2 3molZn(NO3 ) 2 1molZn 3 (PO4 ) 2 16.5gZn3 (PO4 ) 2 :: This is the answer b/c it is lowest 20.5gNa3 PO4 1molNa3 PO4 2molNa3 PO4 385gZn3 (PO4 ) 2 x x x 1 164gNa3 PO4 3molZn(NO3 ) 2 1molZn 3 (PO4 ) 2 32.1gZn3 (PO4 ) 2 - 48 - Name 4. How many liters of oxygen are produced when 3.25-g of KClO3 decomposes into KCl and O2? 2KClO3 2KCl + 3O2 3.25g L? 3.25gKClO3 1molKClO3 3molO2 22.4LO2 x x x 1 122.5gKClO3 2molKClO3 1molO2 0.89LO2 5. When 2.25-g of sodium chloride reacts with excess silver nitrate, 3.45-g of precipitate is formed. What is the percent yield? NaCl + AgNO3 AgCl + NaNO3 2.25g 3.45g 2.25gNacl 1molNaCl 1molAgCl 143.5gAgCl x x x 1 58.5gNaCl 1molNaCl 1molAgCl 5.51gAgCl Actual 3.45g &Yield x100 63% Theoretical 5.51g 6. 4.35-g of C5H12 reacts with 4.0-L of O2. a. How many liters of CO2 are formed? b. How much excess reactant remains? C5H12 + 8O2 4.35g 4.0L 4.35gC5 H12 1molC5 H12 5molCO2 22.4LCO2 x x x 1 72gC5 H12 1molC5 H12 1molCO2 6.76LCO2 4.0LO2 1molO2 5molCO2 22.4LCO2 x x x 1 22.4LO2 8molO2 1molCO2 2.5LCO2 Answer due to being lower 4.0LO2 1molO2 1molC5 H12 72gC5 H12 x x x 1 22.4LO2 8molO2 1molC5 H12 1.61gC5 H12 used up 4.35g 1.61g 2.74gC5 H12leftOver - 49 - 5CO2 L? + 6H2O Name 7. 3.0-g of zinc reacts with silver nitrate to form how many grams of zinc nitrate? Zn + 2AgNO3 Zn(NO3)2 + 2Ag 3.0g ?grams? 3.0gZn 1molZn 1molZn(NO3 ) 2 189gZn(NO3 ) 2 x x x 1 65gZn 1molZn 1molZn(NO3 ) 2 8.72gZn(NO3 ) 2 8. 8.2-mol of barium carbonate decomposes into how many moles of barium oxide. The other product is carbon dioxide. BaCO3 BaO + CO2 8.2mol ?mol 8.2molBaCO3 1molBaO x 8.2molBaO 1 1molBaCO3 9. 4.5-g of sodium hydroxide reacts with 2.0-g of sulfuric acid (H2SO4). How many grams of water are formed? 2NaOH + H2SO4 2HOH + Na2SO4 4.5g 2.0g G? 4.5gNaOH 1molNaOH 2molHOH 18gHOH x x x 1 40gNaOH 2molNaOH 1molHOH 2.0gHOH 2.0gH 2 SO4 1molH 2 SO4 2molHOH 18gHOH x x 1 98gH 2 SO4 1molH 2 SO4 1molHOH 0.73gHOH this is the correct answer : It is lower 10. 8.0-L of butane (C4H10) reacts with oxygen to make 50-g of carbon dioxide. What is the percent yield? 2C4H10 + 13O2 8CO2 + 10H2O 8.0L 50g 8.0LC4 H10 1molC4 H10 8molCO2 44gCO2 x x x 1 22.4LC4 H10 2molC4 H10 1molCO2 62.8gCO2 : Theoretical Actual 50.0 %Yield 79.5% Theoretical 62.8 - 50 - Name 11. 8.5-L of hydrogen reacts with 5.4-L of nitrogen to make… a. how many liters of ammonia (NH3)? b. How many liters of excess reactant remains? 3H2 + 1N2 8.5L 5.4L 2NH3 ?L 8.5LH 2 2 LNH 3 x 5.7 LNH 3 : Answer lower 1 3molH 2 5.4 LN 2 2 LNH 3 x 10.8LNH 3 1 1LN 2 8.5LH 2 1LN 2 x 2.83LN 2UsedUp 1 3LH 2 5.4 2.8 2.6 L left over 12. ** 2.25-g of aluminum sulfate reacts with 3.25-g of sodium phosphate to make 1.0-g of precipitate. What is the percent yield? Al2(SO4)3 + 2Na3PO4 2AlPO4 + 3Na2SO4 2.25g 3.25g 1.0g This is both a limiting reactant problem and a percent yield problem 2.25gAl2 (SO4 ) 3 1molAl2 (SO4 ) 3 2molAlPO4 122gAlPO4 x x x 1 339gAl2 (SO4 ) 3 1molAl2 (SO4 ) 3 1molAlPO4 1.62gAlPO4 :: this is the theoretical amount due to being smaller 3.25gNa3 PO4 1molNa3 PO4 2molAlPO4 122gAlPO4 x x x 1 164gNa3 PO4 2molAlPO4 1molAlPO4 2.41gAlPO4 %Yield Actual 1.0 x100 61.7% Theoretical 1.62 - 51 - Name Chapter 10 Review EHS Chemistry 1. 23.5-g of KClO3 decomposes in the following way: KClO3 KCl + O2 How many grams of O2 was forms? (Make sure to balance the equation) 2. In the reaction: Na2CO3 + H3PO4 Na3PO4 + H2O + CO2 How many grams of Na2CO3 react with the H3PO4 to produce 100L of CO2 at STP? 3. Mercury (II) oxide decomposes to form liquid mercury and oxygen gas. If 5.4 g of mercury (II) oxide decomposes, how many grams of mercury is formed? (Hint: You must start with a correctly balanced chemical reaction) 4. 2.5-g of C4H10 reacts with 0.59-L of O2 at STP to form CO2 and H2O. a. Write the balanced equation. b. How many grams of H2O will be formed? c. How much excess reactant remains? 5. 2.30-g of Barium chloride reacts with 5.45-g of sodium carbonate in a double displacement reaction. How many grams of precipitate will form? (Hint: These are the calculations for the lab that you did). Make sure to use the table of solubilites to determine which substance is the solid precipitate. 6. 32.5-g of Hg(NO3)2 reacts with NH4Cl to make HgCl2 and NH4NO3. When the chemicals were mixed it was discovered that 20.0-g of HgCl2 was formed. What is the percent yield? 7. BONUS: 2.52x1025 atoms of sodium react with 325-L of phosphoric acid gas (H3PO4) at STP. 302.5-L of a gas is given off. What is the percent yield of the reaction? - 52 - Name Chapter 10 Review KEY EHS Chemistry 1. 23.5-g of KClO3 decomposes in the following way: KClO3 KCl + O2 How many grams of O2 was forms? (Make sure to balance the equation) 2KClO3 23.5g 2KCl + 3O2 G? 23.5gKClO3 1molKClO3 3molO2 32gO2 x x x 1 122.5gKClO3 2molKClO3 1molO2 9.2gO2 2. In the reaction: Na2CO3 + H3PO4 Na3PO4 + H2O + CO2 How many grams of Na2CO3 react with the H3PO4 to produce 100L of CO2 at STP? 3Na2CO3 + 2H3PO4 2Na3PO4 + 3HOH + 3CO2 ?g 100L 100LCO2 1molCO2 3molNa2CO3 106gNa2CO3 x x x 1 22.4LCO2 3molCO2 1molNa2CO3 473gNa2CO3 3. Mercury (II) oxide decomposes to form liquid mercury and oxygen gas. If 5.4 g of mercury (II) oxide decomposes, how many grams of mercury is formed? (Hint: You must start with a correctly balanced chemical reaction) 2HgO 5.4g 2Hg ?g - 53 - + O2 Name 5.4gHgO 1molHgO 2molHg 201gHg x x x 1 217gHgO 2molHgO 1molHg 5.0gHg - 54 - Name 4. 2.5-g of C4H10 reacts with 0.59-L of O2 at STP to form CO2 and H2O. a. Write the balanced equation. b. How many grams of H2O will be formed? c. How much excess reactant remains? 2C4H10 + 13O2 8CO2 + 10H2O 2.5g 0.59L ?g 2.5gC4 H10 1molC4 H10 10molH 2O 18gH 2O x x x 58gC4 H10 2molC4 H10 1molH 2O 1 3.88gH 2O 0.59LO2 1molO2 10molH 2O 18gH 2O x x x 22.4LO2 13molO2 1molH 2O 1 0.364gH 2O : LowestAnswer correct 0.59LO2 1molO2 2molC4 H10 58gC4 H10 0.24gC4 H10 x x x 22.4LO2 13molO2 1molC4 H10 1 2.5 0.24 2.26gC4 H10LeftOver 5. 2.30-g of Barium chloride reacts with 5.45-g of sodium carbonate in a double displacement reaction. How many grams of precipitate will form? (Hint: These are the calculations for the lab that you did). Make sure to use the table of solubilites to determine which substance is the solid precipitate. BaCl2 + 2.30g Na2CO3 5.45g - 55 - BaCO3 + ?g:ppt 2NaCl Name 2.30gBaCl2 1molBaCl2 1molBaCO3 197gBaCO3 x x x 1 208gBaCl2 1molBaCl2 1molBaCO3 2.18gBaCO3 ::: Correct Lowest 5.45gNa2CO3 1molNa2CO3 1molBaCO3 197gBaCO3 x x x 1 106gNa2CO3 1molNa2CO3 1molBaCO3 10.1gBaCO3 6. 32.5-g of Hg(NO3)2 reacts with NH4Cl to make HgCl2 and NH4NO3. When the chemicals were mixed it was discovered that 20.0-g of HgCl2 was formed. What is the percent yield? Hg(NO3) + 2NH4C HgCl + 2NH4NO l 2 2 3 32.5g 20.0g 32.5gHg(NO3 ) 2 1molHg(NO3 ) 2 1molHgCl2 272gHgCl2 x x x 1 325gHg(NO3 ) 2 1molHg(NO3 ) 2 1molHgCl2 27.2gHgCl2 Theoretical Actual 20.0g %Yield x100 73.5% Theoretical 27.2g 7. BONUS: 2.52x1025 atoms of sodium react with 325-L of phosphoric acid gas (H3PO4) at STP. 302.5-L of a gas is given off. What is the percent yield of the reaction? 6Na + 2H3PO4 2.52E25 325L - 56 - 2Na3PO4 + 3H2 302.5L Name 2.52x10 25 atomsNa 1molNa 3molH 2 22.4LH 2 x x x 1 6.02x10 23 atomsNa 6molNa 1molH 2 468.5LH 2 325LH 3 PO4 3LH 2 x 487.5LH 2 :: LR due to lowest = theo 1 2LH 3 PO4 actual 302.5L %Yield = x100 64.5% theoretcial 468.5L - 57 -
