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 H 2 + O 2  2 H 2 O 2 No coefficient = 1 2 For every 2 moles of H 2 … 1 mole of O 2 is needed to react… and 2 moles of H 2 O 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 butter How many cupcakes could you make?

General Mole  Mole Conversion Given xMole Ratio= Unknown Amount of given substance in moles mole unknown mole given = Amount of unknown substance in moles

Start with the Balanced Equation Example: If 4.2 mole of H 2 reacts completely with O 2, how many moles of O 2 are needed? 2 H O 2  2 H 2 O

Start with the Balanced Equation Example: If 1.5 mole of H 2 reacts completely, how many moles of H 2 O are formed? 2 H O 2  2 H 2 O

Practice: How many moles of AgCl will be precipitated if 0.46 mole AgNO 3 is reacts with CaCl 2 ? __ AgNO 3 + __ CaCl 2  __ AgCl + __ Ca(NO 3 ) 2 Step 1: Balance the Equation Step 2: Set up conversion

Practice: How many moles of AgCl will be precipitated if 0.46 mole AgNO 3 is reacts with CaCl 2 ? __ AgNO 3 + __ CaCl 2  __ AgCl + __ Ca(NO 3 ) 2 Step 1: Balance the Equation

Practice: How many moles of AgCl will be precipitated if 0.46 mole AgNO 3 reacts with CaCl 2 ? __ AgNO 3 + __ CaCl 2  __ AgCl + __ Ca(NO 3 ) 2 Step 2: Set up conversion 2 1

__H ₂SO₄+ ___ NaOH → ___ Na ₂SO₄+ ___ H ₂0 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 H O 2  2 H 2 O Moles  Grams Conversion Example: If 1.5 mole of H 2 reacts completely, how many grams of H 2 O are formed?

2 H O 2  2 H 2 O Moles  Grams Conversion Example: If 5.1 mole of H 2 reacts completely with O 2, how many grams of O 2 are needed?

Moles  Grams Conversion Practice: How many grams of AgCl will be precipitated if 0.46 mole AgNO 3 reacts with CaCl 2 ?

Gram to Gram Calculations GivenConversionMole RatioConversionUnknown Mass of given substance (grams) X 1 mole Molar mass of given X Mole unknown Mole Given X Molar mass of unknown 1 mole = Mass of unknown substance

Gram to Gram Calculation 1 H ₂SO₄+ 2 NaOH → 1 Na ₂SO₄+ 2 H ₂0 If 600 grams of sodium sulfate are required, how many grams of sodium hydroxide must be used?

Gram to Gram Calculation 1 H ₂SO₄+ 2 NaOH → 1 Na ₂SO₄+ 2 H ₂0 If 325 grams of sodium sulfate are required, how many grams of sulfuric acid must be used? 17

Gram to Gram Calculation 1 H ₂SO₄+ 2 NaOH → 1 Na ₂SO₄+ 2 H ₂0 If 540 grams of sodium hydroxide are available, how much sodium sulfate ( in grams) will be produced? 18

Gram to Gram Calculation 1 H ₂SO₄+ 2 NaOH → 1 Na ₂SO₄+ 2 H ₂0 If 540 grams of sodium hydroxide are available, how many grams of sulfuric acid must be used? 19