Intro to Stoichiometry
What is stoichiometry?
Stoichiometry – Uses mole ratios from balanced equations and information about one compound to determine information about another compound in the equation.
2 H2 + O2 2 H2O
2
No coefficient = 1
2
For every 2 moles of H2…
1 mole of O2 is needed to react…
and 2 moles of H2O are produced
What do those coefficients really mean?
Q: When will I ever use this? A: Baking!
2 cups of flour + 1 stick of butter 1 dozen cupcakes
You have:4 cups of flour + 3 sticks of butterHow many cupcakes could you make?
General Mole Mole Conversion
Given x
Mole Ratio = Unknown
Amount of given substance in moles
mole unknown mole given
= Amount of unknown substance in moles
Start with the Balanced EquationExample:
If 4.2 mole of H2 reacts completely with O2, how many moles of O2 are needed?
2 H2 + 1 O2 2 H2O
Start with the Balanced EquationExample:
If 1.5 mole of H2 reacts completely, how many moles of H2O are formed?
2 H2 + 1 O2 2 H2O
Practice:How many moles of AgCl will be precipitated if
0.46 mole AgNO3 is reacts with CaCl2?
__ AgNO3 + __ CaCl2 __ AgCl + __ Ca(NO3)2
Step 1: Balance the EquationStep 2: Set up conversion
Practice:How many moles of AgCl will be precipitated if
0.46 mole AgNO3 is reacts with CaCl2?
__ AgNO3 + __ CaCl2 __ AgCl + __ Ca(NO3)2
Step 1: Balance the Equation
Practice:How many moles of AgCl will be precipitated if
0.46 mole AgNO3 reacts with CaCl2?
__ AgNO3 + __ CaCl2 __ AgCl + __ Ca(NO3)2
Step 2: Set up conversion
2 1 2 1
__H₂SO₄+ ___NaOH→ ___Na₂SO₄+ ___H₂0
1. How many moles of water will be produced if there are 10 moles of sodium hydroxide?
2. How many moles of sulfuric acid are required if 135 moles of sodium sulfate must be produced?
3. How many moles of sodium hydroxide must be available to produce 17 moles of sodium sulfate?
2 H2 + 1 O2 2 H2O
Moles Grams Conversion
Example:If 1.5 mole of H2 reacts completely, how many grams
of H2O are formed?
2 H2 + 1 O2 2 H2O
Moles Grams Conversion
Example:If 5.1 mole of H2 reacts completely with O2, how many
grams of O2 are needed?
Moles Grams ConversionPractice:
How many grams of AgCl will be precipitated if 0.46 mole AgNO3 reacts with CaCl2?
Gram to Gram CalculationsGiven Conversion Mole Ratio Conversion Unknown
Mass of given substance(grams)
X 1 mole
Molar mass of given
X Mole
unknownMole Given
XMolar mass of
unknown1 mole
= Mass of unknown substance
Gram to Gram Calculation 1H₂SO₄+ 2NaOH→ 1Na₂SO₄+ 2H₂0
If 600 grams of sodium sulfate are required, how many grams of sodium hydroxide must be used?
Gram to Gram Calculation 1H₂SO₄+ 2NaOH→ 1Na₂SO₄+ 2H₂0
• If 325 grams of sodium sulfate are required, how many grams of sulfuric acid must be used?
17
Gram to Gram Calculation 1H₂SO₄+ 2NaOH→ 1Na₂SO₄+ 2H₂0
• If 540 grams of sodium hydroxide are available, how much sodium sulfate ( in grams) will be produced?
18
Gram to Gram Calculation 1H₂SO₄+ 2NaOH→ 1Na₂SO₄+ 2H₂0
• If 540 grams of sodium hydroxide are available, how many grams of sulfuric acid must be used?
19