1. Stoichiometry Chapter 9 Table of Contents
Section 1 Calculating Quantities in Reactions
Section 2 Limiting Reactants and Percentage Yield
Section 3 Stoichiometry and Cars

2. Write the quantities of ingredients you would use to make a sandwich.
Chapter 9
Section 1 Calculating Quantities in Reactions
Write the quantities of ingredients you would use to make a sandwich.
Then determine how many sandwiches you could make from 24 slices of bread.
Calculate how much of each other ingredient is needed.

3. Explain why mole ratios are central to solving stoichiometry problems.
Section 1 Calculating Quantities in Reactions
Chapter 9
Objectives
Use proportional reasoning to determine mole ratios from a balanced chemical equation.
Explain why mole ratios are central to solving stoichiometry problems.
Solve stoichiometry problems involving mass by using molar mass.
Solve stoichiometry problems involving the volume of a substance by using density.

4. Chapter 9: Stoichiometry
The branch of chemistry that deals with quantities of substances in chemical reactions is known as stoichiometry.
Stoichiometry is the proportional relationship between
two or more substances during a chemical reaction.
How much of a reactant is needed to produce a given quantity of product
How much of product is formed from a given quantity of reactant

5. Sec 1: Calculating quantities in reaction
4 different types of problems
Mole  mole
Mass  mass
Volume  Volume
Particle  Particle

6. Remember! 1 mol = 6.022 x particles
Molar mass = mass (g) of 1 mol of atoms (atomic mass)
Volumes of Gases: at STP (standard
temperature and pressure) 1 mol of ANY gas = 22.4 L

7. Interpreting Chemical equations
Balanced equation (given)
Particles: 2 atoms Na react with 1 molecule (2 atoms Cl) to form 2 molecules of NaCl.
Moles: 2 mol Na react with 1 mol (2 mol Cl) to form 2 mol of NaCl.
Mass: 2 mol Na x g/mol = g Na
2 mol Cl x g/mol= g
2 mol NaCl x ( )g/mol = g NaCl
So, g Na reacts with g to form g NaCl

8. Mole Ratios The only way to relate different chemicals.
Must have a balanced equation.
2 mol NO reacts with 1 mol O to form 2 mol NO
No matter how much you have of each, the same Ratio will react. The following are Mole Ratios for the reaction above.
2 mol NO mol O mol NO2
1 mol O mol NO mol NO

9. Interpret this equation
Hint: Balance first!
Particles:
Moles:
Masses:

10. Mole  Mole problems Use mole ratios to solve problems.
How many mol of O2 will react with 7.22 mol NO?
This process is called Stoichiometry– figuring out quantities of substances in chemical reaction

11. The steps of Stoichiometry
Start with what you have and convert to mole.
Use the mole ratio from the balanced chemical equation to find the moles of the new substance you’re interested in.
Convert from moles to desired units.

12. Solving Mass-Mass Problems
Section 1 Calculating Quantities in Reactions
Chapter 9
Solving Mass-Mass Problems

13. What mass of NH3 can be made from 1221 g H2 and excess N2?
Section 1 Calculating Quantities in Reactions
Chapter 9
Problems Involving Mass
Example
What mass of NH3 can be made from 1221 g H2 and excess N2?
N2 + 3H NH3

14. Problems Involving Mass
Section 1 Calculating Quantities in Reactions
Chapter 9
Problems Involving Mass
Example

15. Solving Volume-Volume Problems
Section 1 Calculating Quantities in Reactions
Chapter 9
Solving Volume-Volume Problems

16. Problems Involving Volume
Section 1 Calculating Quantities in Reactions
Chapter 9
Problems Involving Volume
Example
What volume of H3PO4 forms when 56 mL POCl3 completely react? (density of POCl3 = 1.67 g/mL; density of H3PO4 = 1.83 g/mL)
POCl3(l) + 3H2O(l) H3PO4(l) + 3HCl(g)

17. Problems Involving Volume, continued
Section 1 Calculating Quantities in Reactions
Chapter 9
Problems Involving Volume, continued
example

18. Problems Involving Particles,
Section 1 Calculating Quantities in Reactions
Chapter 9
Problems Involving Particles,
For Number of Particles, Use Avogadro’s Number
You can use Avogadro’s number,
6.022  1023 particles/ mol, in stoichiometry problems.
If you are given particles and asked to find particles, Avogadro’s number cancels out.
For this kind of calculation you use only the coefficients from the balanced equation.

19. Solving Particle Problems
Section 1 Calculating Quantities in Reactions
Chapter 9
Solving Particle Problems

20. Problems Involving Particles
Section 1 Calculating Quantities in Reactions
Chapter 9
Problems Involving Particles
Example
How many grams of C5H8 form from 1.89 × 1024 molecules C5H12?
C5H12(l) C5H8(l) + 2H2(g)

21. Problems Involving Particles, continued
Section 1 Calculating Quantities in Reactions
Chapter 9
Problems Involving Particles, continued
Example