<p> Unit 8- STOICHIOMETRY PreAP REVIEW </p><p>2 H2S (g) + 3 O2 (g)  2 SO2 (g) + 2 H2O (g) </p><p>1. In the equation above, 2 molecules react with ____ molecules of O2 to produce ____molecules of sulfur dioxide and ____molecules of water.</p><p>Mole-Mole Calculations </p><p>4Al + 3O2  2Al2O3 2. How many moles of Al are needed to form 2.3 mol of Al2O3? </p><p>3. How many moles of O2 are required to react completely with 0.84 mol of Al?</p><p>4. Calculate the number of moles of Al2O3 formed when 17.2 mol of O2 react with Al.</p><p>Mass-Mass Calculations </p><p>N2 (g) + 3H2 (g)  2NH3 (g)</p><p>5. Calculate the grams of NH3 produced by the reaction of 5.40 grams of H2 with excess N2</p><p>6. How many grams of nitrogen are needed to produce 30.6 grams of ammonia?</p><p>Mixed Stoichiometry Calculations electricity 2 H2O (l)  2 H2 (g) + O2 (g)</p><p>7. How many liters of oxygen are produced @STP when 29.2 grams of water is decomposed?</p><p>8. How many liters of hydrogen are produced when 29.2 grams of water is decomposed? 2 SO2 (g) + O2 (g)  2 SO3 </p><p>9. Assuming STP, how many liters of oxygen are needed to produce 19.8 L of SO3? </p><p>10. How many grams of SO3(g) are formed if 8.45 L of oxygen are used? </p><p>11. How many molecules of oxygen are used to form 160.14 g of sulfur trioxide?</p><p>12. Calcium hydroxide and hydrochloric acid react to form calcium chloride and water as shown in the chemical reaction. If the chemicals are present in exactly the correct ratios to fully use all of the ingredients, how many moles of water would be formed from 5 moles of HCl?</p><p>__ Ca(OH)2 + __ HCl → __ CaCl2 + __ H2O </p><p>13. A student burns 1.50 mol C3H8 according to the following reaction:</p><p>C3H8 + 5O2 3CO2 + 4H2O How many grams of carbon dioxide are produced?</p><p>14. 85 grams of iron reacts with sulfuric acid according to the equation:</p><p>_____ Fe(s) + _____ H2SO4  _____ Fe2(SO4)3(aq) + _____ H2 (g)</p><p> a. How many moles of iron were given?</p><p> b. How many grams of sulfuric acid will be required?</p><p> c. How many grams of iron(III) sulfate will be produced?</p><p> d. How many moles of hydrogen will be produced? e. How many liters, at STP, of hydrogen will be produced?</p><p>Limiting Reagent </p><p>2 Na (s) + Cl2 (g)  2 NaCl (s)</p><p>6.70 mol of Na reacts with 3.20 mol of Cl2 15. What is the limiting reagent?</p><p>16. How many moles of NaCl are produced?</p><p>Mg (s) + 2HCl (aq)  MgCl2 (aq) + H2 </p><p>17. How many grams of H2 can be produced when 4.00 g of HCl is added to 3.00 g of Mg?</p><p>18. What is the volume of the hydrogen when 4.00 g of HCl is added to 3.00 g of Mg?</p><p>19. In the reaction A + B → C + D, if element B is in excess, then the limiting reagent is:</p><p>20. 52 grams of magnesium and grams of hydrochloric acid are placed in a container. Write and balance this reaction in the space provided below:</p><p> a. Which reactant is limiting?</p><p> b. Which reactant is in excess?</p><p> c. How many grams of each product will be created?</p><p> product 1 (______):</p><p> product 2 (______): d. How many grams of the excess reactant will remain when the reaction is complete? </p><p>Percent Yield (You must show all work for stoichiometry as well as the percent yield) </p><p>21. Fe2O3 + 3CO  2Fe + 3CO2 What is the percent yield when 84.8 g of Fe2O3 reacts with an excess of CO and actually yields 57.8 g of Fe ?</p><p>D 22. SiO2 + 3C 揪 SiC + 2CO </p><p>What is the percent yield of silicon carbide when 50.0 g of SiO2 is heated with an excess of C and yields 32.2 g of SiC? </p><p>Questions 23. How much does one mole of an element weigh?</p><p>24. What is the mass of one mole of a compound?</p><p>25. How much space does one mole of a gas occupy?</p><p>26. How many molecules does it take to make a mole?</p><p>27. What is a limiting reagent?</p><p>28. What is theoretical yield? Where do you get it? Can it be affected by sloppy lab technique?</p><p>29. How does actual yield differ from theoretical? Which is usually larger? </p><p>30. Should you use the coefficients when figuring molar mass? Should you use the subscripts?</p>