Stoichiometry Worksheet with Answers

KEY Stoichiometry Review Name - ________________ 1.) Solve for the number of grams of oxygen needed to burn 1.06 ݉‫ ݏ݈݁݋‬of methane, CH4, to produce carbon dioxide and water. Answer - CH4 + 2 O2 1.06 ݉‫ܪܥ ݈݋‬ସ × ଶ ௠௢௟ ைమ × ଵ ௠௢௟ ஼ுర CO2 + 2 H2O  ଷଶ.଴଴ ௚ ைమ ଵ ௠௢௟ ைమ = 67.8 ݃ ܱଶ 2.) A camping Lantern uses the reaction of calcium carbide, CaC2, and water to produce acetylene gas, C2H2, and calcium hydroxide. How many grams of water are required to produce 1.55 ݉‫ ݏ݈݁݋‬of acetylene gas? Answer - CaC2 + 2 H2O 1.55 ݉‫ܥ ݈݋‬ଶ ‫ܪ‬ଶ × C2H2 + Ca(OH)2  ଶ ௠௢௟ ுమ ை ଵ ௠௢௟ ஼మ ுమ × ଵ଼.଴ଶ ௚ ுమ ை = 55.862 ݃ ଵ ௠௢௟ ுమ ை 55.9 ݃ ‫ܪ‬ଶ ܱ 3.) When 7.52 ݃ of lead (II) carbonate are reacted with 27.5 ݈݉ of 3.00 ‫ ܯ‬nitric acid, what mass of PbCO3 + 2 HNO3 lead (II) nitrate will be formed? Answer - 0.0275 ‫ܱܰܪ ܮ‬ଷ × 9.32 ݃ ܾܲ(ܱܰଷ )ଶ Limiting  ଷ.଴଴ ௠௢௟ ுேைయ ଵ ௅ ுேைయ × ଵ ௠௢௟ ௉௕(ேைయ )మ ଶ ௠௢௟ ுேைయ ଵ ௠௢௟ ௉௕஼ைయ 7.52 ݃ ܾܲ‫ܱܥ‬ଷ × ଶ଺଻.ଶ ௚ ௉௕஼ைయ × Pb(NO3)2 + H2CO3  × ଷଷଵ.ଶ ௚ ௉௕(ேைయ )మ ଵ ௠௢௟ ௉௕(ேைయ )మ ଵ ௠௢௟ ௉௕(ேைయ )మ ଵ ௠௢௟ ௉௕஼ைయ × = 13.662 ݃ ܾܲ(ܱܰଷ )ଶ ଷଷଵ.ସ ௚ ௉௕(ேைయ )మ ଵ ௠௢௟ ௉௕(ேைయ )మ = 9.321 ݃ ܾܲ(ܱܰଷ )ଶ 4a.) For the reaction of zinc metal and hydrochloric acid, how many moles of hydrochloric acid are needed to completely react with 12.35 ݃ of zinc? Answer - 12.35 ݃ ܼ݊ × ଵ ௠௢௟ ௓௡ ଺ହ.ଷଽ ௚ ௓௡ × Zn + 2 HCl ଶ ௠௢௟ ு஼௟ ଵ ௠௢௟ ௓௡  ZnCl2 + H2 = 0.3777 ݉‫݈ܥܪ ݈݋‬ b.) What volume of 3.00 ‫ ܯ‬hydrochloric acid is required to react with 12.35 ݃ of zinc? Answer - 12.35 ݃ ܼ݊ × ଵ ௠௢௟ ௓௡ ଺ହ.ଷଽ ௚ ௓௡ × ଶ ௠௢௟ ு஼௟ ଵ ௠௢௟ ௓௡ × ଵ ௅ ு஼௟ ଷ.଴଴ ௠௢௟ ு஼௟ = 0.126 ‫݈ܥܪ ܮ‬ c.) How many moles of hydrogen are produced when 12.35 ݃ of zinc are reacted with the correct amount of hydrochloric acid? Answer - 12.35 ݃ ܼ݊ × ଵ ௠௢௟ ௓௡ ଺ହ.ଷଽ ௚ ௓௡ × ଵ ௠௢௟ ுమ ଵ ௠௢௟ ௓௡ = 0.1889 ݉‫ܪ ݈݋‬ଶ 1 KEY 5a.) If 10.45 ݃ of aluminium is reacted with 66.55 ݃ of copper (II) sulphate, which reactant is in excess? 2 Al + 3 CuSO4 Answer - 10.45 ݃ ‫× ݈ܣ‬ Al Excess  Al2(SO4)3 + 3 Cu  ଵ ௠௢௟ ஺௟ ଶ଺.ଽ଼ ௚ ஺௟ × ଷ ௠௢௟ ஼௨ ଶ ௠௢௟ ஺௟ 66.55 ݃ ‫ܱܵݑܥ‬ସ × × ଺ଷ.ହହ ௚ ஼௨ ଵ ௠௢௟ ஼௨ ଵ ௠௢௟ ஼௨ௌைర × ଵହଽ.଺ଵ ௚ ஼௨ௌைర = 36.9217 ݃ ‫ݑܥ‬ ଷ ௠௢௟ ஼௨ ଷ ௠௢௟ ஼௨ௌைర × ଺ଷ.ହହ ௚ ஼௨ ଵ ௠௢௟ ஼௨ = 26.4974 ݃ ‫ݑܥ‬ b.) Calculate the mass of the excess reactant. Answer - 66.55 ݃ ‫ܱܵݑܥ‬ସ × ଵ ௠௢௟ ஼௨ௌைర × ଵହଽ.଺ଵ ௚ ஼௨ௌைర ଶ ௠௢௟ ஺௟ ଷ ௠௢௟ ஼௨ௌைర × 10.45 ݃ − 7.4996 ݃ = 2.9503 ݃ ଶ଺.ଽ଼ ௚ ஺௟ ଵ ௠௢௟ ஺௟ = 7.4996 ݃ ‫݈ܣ‬ 2.95 ݃ ‫݈ܣ‬ c.) Calculate the mass of each product. Answer – Cu = 26.4908 ݃ 66.55 ݃ ‫ܱܵݑܥ‬ସ × ଵ ௠௢௟ ஼௨ௌைర ଵହଽ.଺ହ ௚ ஼௨ௌைర × ଵ ௠௢௟ ஺௟మ ௌைర ଷ ௠௢௟ ஼௨ௌைర × ଷସଶ.ଵସ ௚ ஺௟మ (ௌைర )య ଵ ௠௢௟ ஺௟మ ௌைర = 47.54 ݃ ‫݈ܣ‬ଶ (ܱܵସ )ଷ 6.) If 111.7 ݃ of iron (II) and 212.7 ݃ of chlorine gas completely react, how many grams of product are formed? Answer - Fe + Cl2  111.7 ݃ ‫× ݁ܨ‬ FeCl2 ଵ ௠௢௟ ி௘ ହହ.଼ହ ௚ ி௘ 212.7 ݃ ‫݈ܥ‬ଶ × × ଵ ௠௢௟ ஼௟మ ଻଴.ଽ଴ ௚ ஼௟మ ଵ ௠௢௟ ி௘஼௟మ × ଵ ௠௢௟ ி௘ × ଵ ௠௢௟ ி௘஼௟మ ଵ ௠௢௟ ஼௟మ ଵଶ଺.଻ହ ௚ ி௘஼௟మ × ଵ ௠௢௟ ி௘஼௟మ ଵଶ଺.଻ହ ௚ ி௘஼௟మ ଵ ௠௢௟ ி௘஼௟మ = 253.5 ݃ ‫݈ܥ݁ܨ‬ଶ = 380.3 ݃ ‫݈ܥ݁ܨ‬ଶ Lower amount is correct amount . . . . so 253.5 ‫݈ܥ݁ܨ‬ଶ 2 KEY 7.) If you mix 15.50 ݃ of lead (II) nitrate and 3.81 ݃ of sodium chloride, what mass of each product is produced? Pb(NO3)2 + 2 NaCl Answer - 15.50 ݃ ܾܲ(ܱܰଷ )ଶ × Limiting  3.81 ݃ ܰܽ‫× ݈ܥ‬ 3.81 ݃ ܰܽ‫× ݈ܥ‬ 2 NaNO3 + PbCl2  ଵ ௠௢௟ ௉௕(ேைయ )మ ଷଷଵ.ଶ ௚ ௉௕(ேைయ )మ ଵ ௠௢௟ ே௔஼௟ ହ଼.ସସ ௚ ே௔஼௟ ଵ ௠௢௟ ே௔஼௟ ହ଼.ସସ ௚ ே௔஼௟ × × × ଶ ௠௢௟ ே௔ேைయ ଵ ௠௢௟ ௉௕(ேைయ )మ ଶ ௠௢௟ ே௔ேைయ ଶ ௠௢௟ ே௔஼௟ ଵ ௠௢௟ ௉௕஼௟మ ଶ ௠௢௟ ே௔஼௟ × × × ଼ହ.଴଴ ௚ ே௔ேைయ ଼ହ.଴଴ ௚ ே௔ேைయ ଵ ௠௢௟ ே௔ேைయ ଼ହ.଴଴ ௚ ௉௕஼௟మ ଵ ௠௢௟ ௉௕஼௟మ ଵ ௠௢௟ ே௔ேைయ = 7.995 ݃ ܱܰܽܰଷ = 5.542 ݃ ܱܰܽܰଷ = 9.065 ݃ ܾܲ‫݈ܥ‬ଶ 5.54 ݃ ܱܰܽܰଷ 9.07 ݃ ܾܲ‫݈ܥ‬ଶ 8.) 2.0 ‫ ܮ‬of 0.60 ‫ ܯ‬FeCl3 solution are mixed with 1.0 ‫ ܮ‬of 0.90 ‫ ܯ‬BaCl2 solution. No reaction occurs. What is the concentration of each compound in the final solution? Answer – FeCl3  ‫ܥ‬ௗ௜௟ = ஼೎೚೙೎ ×௏೎೚೙೎ BaCl2  ‫ܥ‬ௗ௜௟ = ஼೎೚೙೎ ×௏೎೚೙೎ ௏೏೔೗ ௏೏೔೗ ‫ܥ‬ௗ௜௟ = ‫ܥ‬ௗ௜௟ = (଴.଺଴)(ଶ.଴) (ଶ.଴ ାଵ.଴) (଴.ଽ଴)(ଵ.଴) (ଶ.଴ ାଵ.଴) ‫ܥ‬ௗ௜௟ = 0.40 ‫݈ܥ݁ܨ ܯ‬ଷ ‫ܥ‬ௗ௜௟ = 0.30 ‫݈ܥܽܤ ܯ‬ଶ 3