Stoichiometric Calculations

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Stoichiometric Calculations
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Stoichiometric Calculations
It only looks hard.
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Stoichiometric Calculations
It only looks hard. Honest.
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Stoichiometric Calculations

• K H2O ? KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 1 Balance the equation.

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 1 Balance the equation.

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 2 Ask yourself,
• What do you know?

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 2 Ask yourself,
• What do you know?

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 2 Ask yourself,
• What do you know?
• I know how many moles of K

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 3 Ask yourself,
• What do you need to know?
• I know how many moles of K

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 3 Ask yourself,
• What do you need to know?
• I know how many moles of K

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 3 Ask yourself,
• What do you need to know?
• I know how many moles of K
• I need to know moles of H2

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 4 Use the equation to find the ratio of
  unknown to known

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 4 Use the equation to find the ratio of
  unknown to known
• moles H2 1
• moles K 2

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 5 multiply the known number by the ratio

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 5 multiply the known number by the ratio
• unknown
• known x known unknown

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 5 multiply the known number by the ratio
• mol H2
• mol K x mol K mol H2

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 5 multiply the known number by the ratio
• 1 mol H2
• 0.04 mol K x 2 mol K 0.02 mol H2

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 6 the answer should have the same number
  of significant digits
• 1 mol H2
• 0.04 mol K x 2 mol K 0.02 mol H2

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Stoichiometric Calculations

• 2K 2H2O ? 2KOH H2
• If you use 0.04 mol of K,
• how much H2 will you produce?
• Step 6 the answer should have the same number
  of significant digits
• 1 mol H2
• 0.04 mol K x 2 mol K 0.02 mol H2

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In-class work

1. Solve practice problems 9 10 on page 359.
2. Choose a chemical equation from chapter 10.
   Dont use one that has all the coefficients 1.
3. Write it as a problem similar to problem 9 or 10.
4. Trade with someone. You solve theirs and they
   solve yours.