# Chapter 9 Chemical Equations & Reaction Stoichiometry.

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Chapter 9 Chemical Equations & Reaction Stoichiometry

2 Chemical Equations Symbolic representation of a chemical reaction that shows: 1.reactants on left side of reaction 2.products on right side of equation 3.relative amounts of each using stoichiometric coefficients

3 Chemical Equations Attempt to show on paper what is happening at the laboratory and molecular levels.

4 Chemical Equations Look at the information an equation provides:

5 Chemical Equations Look at the information an equation provides: reactants yields products

6 Chemical Equations Look at the information an equation provides: reactants yields products 1 formula unit 3 molecules 2 atoms 3 molecules

7 Chemical Equations Look at the information an equation provides: reactants yields products 1 formula unit 3 molecules 2 atoms 3 molecules 1 mole 3 moles 2 moles 3 moles

8 Chemical Equations Look at the information an equation provides: reactants yields products 1 formula unit 3 molecules 2 atoms 3 molecules 1 mole 3 moles 2 moles 3 moles 159.7 g 84.0 g 111.7 g 132g

9 Chemical Equations Law of Conservation of Matter – There is no detectable change in quantity of matter in an ordinary chemical reaction. – Balanced chemical equations must always include the same number of each kind of atom on both sides of the equation. – This law was determined by Antoine Lavoisier. Propane,C 3 H 8, burns in oxygen to give carbon dioxide and water.

10 Calculations Based on Chemical Equations Can work in moles, formula units, etc. Frequently, we work in mass or weight (grams or kg or pounds or tons).

11 Calculations Based on Chemical Equations Example 1: How many CO molecules are required to react with 25 formula units of Fe 2 O 3 ?

12 Calculations Based on Chemical Equations Example 3-2: How many iron atoms can be produced by the reaction of 2.50 x 10 5 formula units of iron (III) oxide with excess carbon monoxide?

13 Calculations Based on Chemical Equations Example 3-2: How many iron atoms can be produced by the reaction of 2.50 x 10 5 formula units of iron (III) oxide with excess carbon monoxide?

14 Calculations Based on Chemical Equations Example 2: How many iron atoms can be produced by the reaction of 2.50 x 10 5 formula units of iron (III) oxide with excess carbon monoxide?

15 Calculations Based on Chemical Equations Example 3-3: What mass of CO is required to react with 146 g of iron (III) oxide?

16 Calculations Based on Chemical Equations Example 3: What mass of CO is required to react with 146 g of iron (III) oxide?

17 Calculations Based on Chemical Equations Example 3-3: What mass of CO is required to react with 146 g of iron (III) oxide?

18 Calculations Based on Chemical Equations Example 4: What mass of carbon dioxide can be produced by the reaction of 0.540 mole of iron (III) oxide with excess carbon monoxide?

19 Calculations Based on Chemical Equations Example 3-4: What mass of carbon dioxide can be produced by the reaction of 0.540 mole of iron (III) oxide with excess carbon monoxide?

20 Calculations Based on Chemical Equations Example 3-4: What mass of carbon dioxide can be produced by the reaction of 0.540 mole of iron (III) oxide with excess carbon monoxide?

21 Calculations Based on Chemical Equations Example 5: What mass of iron (III) oxide reacted with excess carbon monoxide if the carbon dioxide produced by the reaction had a mass of 8.65 grams? You do it!

22 Calculations Based on Chemical Equations Example 5: What mass of iron (III) oxide reacted with excess carbon monoxide if the carbon dioxide produced by the reaction had a mass of 8.65 grams?

23 Limiting Reactant Concept Kitchen example of limiting reactant concept. 1 packet of muffin mix + 2 eggs + 1 cup of milk  12 muffins How many muffins can we make with the following amounts of mix, eggs, and milk?

24 Limiting Reactant Concept Mix PacketsEggsMilk 11 dozen1 gallon limiting reactant is the muffin mix 21 dozen1 gallon 31 dozen1 gallon 41 dozen1 gallon 51 dozen1 gallon 61 dozen1 gallon 71 dozen1 gallon limiting reactant is the dozen eggs

25 Limiting Reactant Concept Example 8: What is the maximum mass of sulfur dioxide that can be produced by the reaction of 95.6 g of carbon disulfide with 110. g of oxygen?

26 Limiting Reactant Concept Example 8: What is the maximum mass of sulfur dioxide that can be produced by the reaction of 95.6 g of carbon disulfide with 110. g of oxygen?

27 Limiting Reactant Concept Example 8: What is the maximum mass of sulfur dioxide that can be produced by the reaction of 95.6 g of carbon disulfide with 110. g of oxygen?

28 Limiting Reactant Concept Example 8: What is the maximum mass of sulfur dioxide that can be produced by the reaction of 95.6 g of carbon disulfide with 110. g of oxygen?

29 Limiting Reactant Concept What do we do next? You do it!

30 Limiting Reactant Concept Which is limiting reactant? Limiting reactant is O 2. What is maximum mass of sulfur dioxide? Maximum mass is 147 g.

31 Percent Yields from Reactions Theoretical yield is calculated by assuming that the reaction goes to completion. – Determined from the limiting reactant calculation. Actual yield is the amount of a specified pure product made in a given reaction. – In the laboratory, this is the amount of product that is formed in your beaker, after it is purified and dried. Percent yield indicates how much of the product is obtained from a reaction.

32 Percent Yields from Reactions Example 9: A 10.0 g sample of ethanol, C 2 H 5 OH, was boiled with excess acetic acid, CH 3 COOH, to produce 14.8 g of ethyl acetate, CH 3 COOC 2 H 5. What is the percent yield?

33 Percent Yields from Reactions

34 Percent Yields from Reactions

35 Percent Yields from Reactions

36 Percent Yields from Reactions