Review Answers with step-by-step examples

1. Review Answers with step-by-step examples

2. Vocabulary Terms • Stoichiometry: • the calculation of quantities in chemical equation. • Limiting Reagent: • the reactant that determines the amount of product in a reaction. • Excess Reagent: • A quantity of a reactant that is more than enough to react with a limiting reagent.

3. Percent Yield: • the ratio of the actual yield to the theoretical yield. • Actual Yield: • the amount of product formed when a reaction is carried out in the lab. • Theoretical Yield: • the calculated amount of product formed during a reaction.

4. Important Things To Remember: • Always start with a balanced equation! • Remember that you have to go through moles to convert from substance A to substance B.

5. 1. _1_ CaCl2 + _2_ AgNO­3_1_ Ca(NO3)2 + _2_ AgCl • How many grams of silver chloride are produced when 45 g of calcium chloride react with excess silver nitrate? = = = 0.405 molCaCl2 0.811 mol AgCl 116.38 g AgCl

6. __ C3H8+ _5_ O2­ _4_H2O + _3_CO2 • How many moles of O2­ should be supplied to burn 1 mol of C3H8 (propane) molecules in a camping stove? (write down the equation first; this is a simple Combustion equation and remember that it must be balanced before you continue.) If I had asked for grams instead of molecules, then the last step would be: = 5 mol O2 = Molecules = 160 g O2

7. _4_ Al + _3_ O2 _2_ Al2O3 • Calculate the mass of alumina (Al2O3) produced when 100 g of aluminum burns in oxygen. (write down the equation first; this is a simple Decomposition equation and remember that it must be balanced before you continue.) = 3.7 mol Al = 1.85 mol Al2O3 = 188.7 g Al2O3

8. Review Answers