Gas Stoichiometry

1
Gas Stoichiometry

• I know you are SO happy you get to do
  stoichiometry again!

2
Two Types of Gas Stoichiometry Problems

1. STP gases
2. Non-STP gases

3
What to do?

• Write a reaction.
• Find moles (gram-mole conversions, molarity, and
  ideal gas law)
• Do a stoichiometric conversion between chemicals
• Answer the question
• 22.4 L/mol for STP gases
• PV nRT for non-STP gases

4
Example 1

• What volume of hydrogen gas will form at STP when
  30.0 g of sodium react with an excess of
  hydrochloric acid, HCl?

5
Example 2

• What mass of potassium chlorate will be needed to
  make 500. mL of oxygen at 25.0 oC and 800. torr?

6
Example 3

• What volume (L) of oxygen will form when 40.0g of
  calcium chlorate decompose at 352oC and 901 torr?

7
Example 4

• What volume of hydrogen at STP will form when
  2.00 g of calcium react with an excess of water?

8
Limiting Reactant Gas Stoichiometry

1. Write a reaction.
2. Find moles for both reactants (gram-mole
   conversion, molarity, or ideal gas)
3. Determine limiting (divide by coefficients,
   choose smaller one as the LR)
4. Answer the question

9
Example 5

• What volume of hydrogen will form at 30.0oC and
  790. torr when 6.60g of zinc react with 30.0 mL
  of 6.00 M HCl?

10
Example 6

• What volume of carbon dioxide at 300. oC and
  1000. mmHg will form when 50.0 g of carbon react
  with 90.0 g of oxygen?

11
Example 7

• What volume of hydrogen will form at 45.0oC and
  750. mmHg will form when 45.0 mL of 0.500M
  sulfuric acid reacts with 30.0 g of calcium?