The document provides instructions on stoichiometry calculations using the decomposition of hydrogen peroxide as an example. It explains how to write and balance chemical equations, determine the mole ratios from coefficients, and use mole ratios to convert between amounts of reactants and products in moles, grams, and liters. Sample calculations are shown for determining moles, liters, and grams of reactants or products given amounts of other substances.

1. Stoichiometry

2. You already know... In a balanced equation the coefficients are MOLES. 2H 2 + O 2 -> 2H 2 O 2 moles Hydrogen, 1 mole Oxygen, 2 moles H 2 O How to Calculate Molar Mass: H 2 O = H 2 x 1.01 = 2.02 O 1 x 16.00 = 16.00 18.02 g/mol 1 mole of anything is 22.42 L examples: 1 mole water = 22.42 L 1 mole H 2 SO 4 = 22.42 L 1 mole acetic acid = 22.42 L

3. Before the Math Balance the equation. You need the coefficients. Look at what numbers the question provides. Start with the number given. Look at what the question is asking for. This is where you stop. It is also the correct label.

4. The Math Step 1: Get to the mole. Step 2: Mole to mole ratio from the balanced equation. Step 3: Use the mole to get to what you want. *KEEP LIKE TERMS DIAGONAL.

5. Finding Moles (this is going to be the first step in all the other types of problems) How many moles of oxygen are formed if 1.34 moles of H 2 O 2 completely decomposes? 1) Write and balance: 2H 2 O 2 -> 2H 2 O + O 2 2:2:1 2) Do the math = .67 mol O 2 1.34 mol H 2 O 2 (from the problem) 1 mol O 2 (from equation) 2 mol H 2 O 2 (from equation)

6. Finding Liters If I produce 2.4 L of oxygen in the decomposition of H 2 O 2 , how many L of H 2 O 2 did I start with? 1) Write and balance: 2H 2 O 2 -> 2H 2 O + O 2 2:2:1 2) Do the math: = 4.8 L H 2 O 2 2.4 L O 2 1 mol O 2 2 mol H 2 O 2 22.42 L H 2 O 2 22.42 L O 2 1 mol O 2 1 mol H 2 O 2

7. Finding Grams In the decomposition of H 2 O 2 , how many grams of H 2 O 2 are required to produce 3.7g of water? 1) Write and balance: 2H 2 O 2 -> 2H 2 O + O 2 2:2:1 2) Because it is grams you need molar masses: O 2 = 32.00 g/mol, H 2 O = 18.02 g/mol, H 2 O 2 = 34.02 g/mol 3)Do the math. = 7.02 g H 2 O 2 3.7 g H 2 O 1 mol H 2 O 2 mol H 2 O 2 34.02 g H 2 O 2 18.02 g H 2 O 2 mol H 2 O 1 mol H 2 O 2

8. Grams to Liters? The mole allows for any calculation. In the decomposition of H 2 O 2 , how many L of H 2 O 2 are required to produce 1.5 g of water? 1) Write and balance: 2H 2 O 2 -> 2H 2 O + O 2 2:2:1 2) Do the math: = 1.87 L H 2 O 2 1.5 g H 2 O 1 mol H 2 O 2 mol H 2 O 2 22.42 L H 2 O 2 18.02 g H 2 O 2 mol H 2 O 1 mol H 2 O 2