1. CHAPTER 12 STOICHIOMETRY
Chemistry 12.1
CHAPTER 12
STOICHIOMETRY

2. The Arithmetic of Equations
12.1
The Arithmetic of Equations
More than 3000 cocoons are needed to produce enough silk to make just one elegant Japanese kimono. Like silk manufacturers, chemists must know how much reactant they need to make a certain amount of product. Determining the quantities of reactants and products in a reaction requires a balanced chemical equation.

3. Using Everyday Equations
12.1
Using Everyday Equations
Using Everyday Equations
How is a balanced equation like a recipe?

4. Using Everyday Equations
12.1
Using Everyday Equations
A balanced chemical equation provides the same kind of quantitative information that a recipe does.
A cookie recipe tells you the number of cookies that you can expect to make from the listed amounts of ingredients. Using Models How can you express a cookie recipe as a balanced equation?

5. Using Balanced Chemical Equations
12.1
Using Balanced Chemical Equations
Using Balanced Chemical Equations
How do chemists use balanced chemical equations?

6. Using Balanced Chemical Equations
12.1
Using Balanced Chemical Equations
Chemists use balanced chemical equations to calculate how much reactant is needed or how much product is formed in a reaction.
The calculation of quantities in chemical reactions is a subject of chemistry called stoichiometry.

7. Interpreting Chemical Equations
12.1
Interpreting Chemical Equations
A balanced chemical equation can be interpreted in terms of different quantities, including numbers of atoms, molecules, or moles; mass; and volume.

8. Interpreting Chemical Equations
12.1
Interpreting Chemical Equations
Number of Atoms
The balanced chemical equation for the formation of ammonia can be interpreted in several ways. Predicting How many molecules of NH3 could be made from 5 molecules of N2 and 15 molecules of H2?

9. Interpreting Chemical Equations
12.1
Interpreting Chemical Equations
Number of Molecules
The balanced chemical equation for the formation of ammonia can be interpreted in several ways. Predicting How many molecules of NH3 could be made from 5 molecules of N2 and 15 molecules of H2?

10. Interpreting Chemical Equations
12.1
Interpreting Chemical Equations
Moles
The balanced chemical equation for the formation of ammonia can be interpreted in several ways. Predicting How many molecules of NH3 could be made from 5 molecules of N2 and 15 molecules of H2?

11. Interpreting Chemical Equations
12.1
Interpreting Chemical Equations
Mass
The balanced chemical equation for the formation of ammonia can be interpreted in several ways. Predicting How many molecules of NH3 could be made from 5 molecules of N2 and 15 molecules of H2?

12. Chemical Calculations
12.2
Chemical Calculations
The effectiveness of car’s air bags is based on the rapid conversion of a small mass of sodium azide into a large volume of gas. The entire reaction occurs in less than a second. You will learn how to use a balanced chemical equation to calculate the amount of product formed in a chemical reaction.

13. Writing and Using Mole Ratios
12.2
Writing and Using Mole Ratios
In chemical calculations, mole ratios are used to convert between moles of reactant and moles of product, between moles of reactants, or between moles of products.

14. Writing and Using Mole Ratios
12.2
Writing and Using Mole Ratios
Mole-Mole Calculations
A mole ratio is a conversion factor derived from the coefficients of a balanced chemical equation interpreted in terms of moles.

15. 12.2
Manufacturing plants produce ammonia by combining nitrogen with hydrogen. Ammonia is used in cleaning products, fertilizers, and in the manufacture of other chemicals.

16. 12.2

17. for Sample Problem 12.2
Problem Solving Solve Problem 12 with the help of an interactive guided tutorial.

18. Writing and Using Mole Ratios
12.2
Writing and Using Mole Ratios
Mass-Mass Calculations

19. 12.3
In this Hubble Space Telescope image, clouds of condensed ammonia are visible covering the surface of Saturn.

20. 12.3

21. Limiting Reagent and Percent Yield
12.3
Limiting Reagent and Percent Yield
If a carpenter had two tabletops and seven table legs, he could only build one four-legged table. The number of table legs is the limiting factor in the construction of four-legged tables. Similarly, in chemistry, the amount of product made in a chemical reaction may be limited by the amount of one or more of the reactants.

22. Limiting and Excess Reagents
12.3
Limiting and Excess Reagents
In a chemical reaction, an insufficient quantity of any of the reactants will limit the amount of product that forms.
The limiting reagent is the reagent that determines the amount of product that can be formed by a reaction.

23. Limiting and Excess Reagents
12.3
Limiting and Excess Reagents
In the reaction of nitrogen and hydrogen, hydrogen is the limiting reagent. Nitrogen is the reagent that is not completely used up in the reaction. The reagent that is not used up is called the excess reagent.

24. 12.7

25. 12.7 1 2

26. 12.7 3

27. 12.8

28. 12.8

29. 12.8

30. Percent Yield 12.3 What does the percent yield of a reaction measure?

31. A batting average is actually a percent yield.
12.3
Percent Yield
The percent yield is a measure of the efficiency of a reaction carried out in the laboratory.
A batting average is actually a percent yield.
A batting average is actually a percent yield.

32. 12.3
Percent Yield
The percent yield is the ratio of the actual yield to the theoretical yield expressed as a percent.

33. 12.9

34. 12.9

35. 12.9

36. 12.10

37. 12.10