Name: _____________________ Hr: ___ College Chemistry Unit 4: Chemical Equations and Stoichiometry Test Practice Problems Moles and Percent Composition 1. What is the percent composition of the element carbon in CH3COOH? Show your work. 2. What is the empirical formula for nickel (II) iodide, with % composition 18.8% Ni and 81.2% I? Show your work. 3. How many atoms are there in 1.5 moles of gold? Show your work. 4. How many grams are there in 0.549 mole of SiO2? Show your work. Types of Reactions and Product Prediction 5. What type of reaction is: 2H2O2  2H2O + O2 6. What type of reaction is: Zn + CuSO4  ZnSO4 + Cu 7. What type of reaction is: 2H2 + O2  2H2O 8. What type of reaction is: CuSO4 + 2NaOH  Cu(OH)2 + Na2SO4 9. Which of the following elements can replace zinc in ZnCl2: K, Pb, Al, Au? Explain why. 10. Predict the products of the following reactions: a. Ag + S8 → b. Mg + Zn(NO3)2 → c. Ca3(PO4)2 + Al2S3 → d. K + PbF2 → e. C2H2 + O2→ Stoichiometry 11. If you mix 0.995 mol of LiOH with excess CO2, how many grams of Li2CO3 would form? Use the unbalanced equation below: LiOH + CO2  Li2CO3 + H2O 12. If 5.00 g of each of the reactants is used in the equation below, how much of the product is formed? Don’t forget to balance! Na2O + CO2 + H2O  NaHCO3 13. For question #12, what is the limiting reactant? 14. For question #12, what is the % yield if 8.00 g of NaHCO3 is actually produced when you do the experiment? Show your work. Molar Volume of a Gas 15. Use the following equation to solve this problem: Cl2(g) + 2HBr(g)  Br2(g) + 2HCl(g) Beginning with 80.0 g of Cl2 and 40.0 g of HBr, what volume of Br2 will be produced at STP? 16. Write the equation for the combustion of methane (CH4). Make sure to balance it. How many liters of CO2 would be formed from burning 50.0 g of methane (at STP)? Net Ionic Equations 17. Write the net ionic equation for the following reaction: 2NaCl + Pb(NO3)2  PbCl2 + 2NaNO3 18. Write the balanced molecular equation, complete ionic equation (before canceling spectators), and net ionic equation if you mix potassium sulfate solution with strontium nitrate solution. Balanced Molecular: Complete Ionic: Net Ionic: