Name Period CRHS Academic Chemistry Stoichiometry Practice Problems Due Date Assignment On-Time (100) Late (70) 9.1 9.2 9.3 9.4 9.5 Warm-Up EC Notes, Homework, Exam Reviews and Their KEYS located on CRHS Academic Chemistry Website: https://cincochem.pbworks.com
Page 2 of 12 Unit 9 HW WARM-UPS Day 1 Day 7 Day 2 Day 8 Day 3 Day 9 Day 4 Day 10 Day 5 Day 11 Day 6 Day 12 9.1 REVIEW OF CONVERSIONS AND DIMENSIONAL ANALYSIS
Unit 9 HW Page 3 of 12 1. What is molar mass of H2SO3? 2. How many particles in 2.85 moles of Sn? 3. How many moles in 25.5 g of Ca? 4. What is the volume, at STP, of 3.65 mol H 2 5. How many particles are in 9.80 moles of HCl? 6. How many grams in 3.5 moles of Mg? 7. How many moles are in 2.55 liters of C 2H 6 gas at STP? 8. What is the number of moles in 65 g of NO 2?
Page 4 of 12 HW 9.2 Mole-Mole Conversions Unit 9 HW 1. Complete the chart. N 2 + H 2 NH 3 Conserved? Atoms + Mass + Moles + Molecules + 2. Balance the following equation C4H8 + O2 CO2 + H2O Complete the following mole ratios C4H8 O2 O2 C4H8 C4H8 O2 CO2 H2O CO2 H2O Balance the reaction, answer the questions that follow. Use dimensional analysis, show units, and show work. 3. C (s) + SO2 (g) CS2 (l) + CO (g) a. How many moles of CS 2 can be formed when 4.8 moles of solid carbon reacts with sulfur dioxide? b. How many moles of SO 2 are needed to form 3.7 moles of CO?
c. How many moles of C are needed to react with 9.2 moles of SO 2? Unit 9 HW Page 5 of 12 4. KClO3 KCl + O2 a. How many moles of potassium chloride (KCl) can be formed when 12.2 moles of potassium chlorate (KClO 3) decompose? b. How many moles of oxygen gas can be formed when 2.9 moles of KCl are formed?
Page 6 of 12 Unit 9 HW HW 9.3 MIXED STOICHIOMETRY CONVERSIONS Using the following reaction, answer questions 1-4. Use dimensional analysis, show units, and show work. K + Cl2 KCl 1. How many grams of KCl can be produced from 2.5 grams of potassium? (Hint: balance reaction, calculate molar mass of each substance) 2. How many moles of KCl can be produced from 20.0 g of chlorine gas, Cl 2? 3. How many grams of KCl can be produced from 1.0 gram of chlorine gas, Cl 2? 4. How many liters of chlorine is required to produce 16.5 g of KCl?
Unit 9 HW Page 7 of 12 Using the following reaction, answer questions 5-7. Use dimensional analysis, show units, and show work. Fe + S8 FeS 5. The most common form (allotrope) of sulfur found in nature is α-cyclo-octosulfur, S 8. What mass of iron is needed to react with 16 grams of sulfur (S 8) in this form? 6. How many grams of FeS can be produced from 16 grams of sulfur (S8)? 7. How many moles of FeS can be produced from 6.5 moles of iron? Using the following reaction, answer questions 8-10. Use dimensional analysis, show units, and show work. NaClO3 NaCl + O2 8. Sodium chlorate (NaClO 3) is a weed killer powder that can ignite at temperatures over 250 C. If 12 grams of NaClO 3 is decomposed in an open flame, how many grams of oxygen gas can be produced?
Page 8 of 12 Unit 9 HW 9. If 32 grams of sodium chloride, NaCl, are produced, how many liters of oxygen gas will also be produced? 10. If 13.5 L of oxygen are produced, how many moles of NaClO 3 were decomposed?
HW 9.4 Limiting Reactant Unit 9 HW Page 9 of 12 Balance the reaction, answer the questions that follow. Use dimensional analysis, show units, and show work. S + O2 SO2 1. If 5.00 grams of S and 8.00 grams of O 2 are used to produce SO 2, which is the limiting reactant? 2. If 24.0 grams of S and 15.0 grams of O 2 are used to produce SO 2, which is the limiting reactant? _2_KMnO4 + _1_H2SO4 _1_K2SO4 + _1_Mn2O7 + _1_ H2O 3. If 500.0 grams of KMnO 4 and 200.0 grams of H 2SO 4 are used to produce K 2SO 4, which is the limiting reactant? 4. If 400.0 grams of KMnO 4 and 700.0 grams of H 2SO 4 are used to produce Mn 2O 7, which is the limiting reactant?
Page 10 of 12 HW 9.5 Percent Yield Unit 9 HW Balance the reaction, answer the questions that follow. Use dimensional analysis, show units, and show work. Ba(NO3)2 + Na2SO4 BaSO4 + NaNO3 A chemist began with 75.00 g of Ba(NO 3) 2. After collecting and drying the product, 64.45 g of BaSO 4 was obtained. 5. What was the actual yield of BaSO 4? 6. What is the theoretical yield of BaSO 4? 7. What is the percent yield of BaSO 4? A chemist began with 150.0 g of Na 2SO 4. After collecting and drying the product, 142.8 g of NaNO 3 was obtained. 8. What was the actual yield of NaNO 3? 9. What is the theoretical yield of NaNO 3? 10. What is the percent yield of NaNO 3?
Unit 9 HW Page 11 of 12 20 Common Polyatomic Ions Name Ion Name Ion acetate C 2H 3O 2 or CH 3COO hypochlorite ClO ammonium NH 4 +1 nitrate NO 3 carbonate CO 3-2 nitrite NO 2 chlorate ClO 3 perchlorate ClO 4 chlorite ClO 2 permanganate MnO 4 chromate CrO 4-2 phosphate PO 4-3 cyanide CN phosphite PO 3-3 dichromate Cr 2O 7-2 silicate SiO 3-2 hydrogen carbonate HCO 3 sulfate SO 4-2 hydroxide OH sulfite SO 3-2
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