1. Classic Butter Cookies 2 1/2 cups all-purpose flour 1 cup butter 1/2 cup white sugar 2 eggs 1/2 teaspoon almond extract Bake at 350ºF for 10 minutes. Yields 20 3” cookies
If only one egg was available, but as much of the other ingredients as you needed, how many cookies would you make?
2. If 4 eggs were available, how many cookies could you make if you had all of the other ingredients? How much flour would you need?
3. If 40 3” cookies were baked, how many cups of flour were used?
If only one egg was available, but as much of the other ingredients as you needed, how many cookies would you make? How much sugar and butter would you use?
If 3 eggs were available, how much flour, butter, and sugar would you need? How many cookies would you make?
If 40 3” cookies were baked, how many cups of flour were used?

2. Stoichiometry
The study of the quantitative, or measurable, relationships that exist in chemical formulas and chemical reactions.

3. Write a reaction for the combustion of glucose, C6H12O6
If two moles of glucose reacts with an excess of oxygen, how many moles of water are produced?
2. If 3 moles of carbon dioxide are produced, how many moles of glucose were consumed (used)?
3. How many moles of oxygen are needed to completely react with 1.94 moles of glucose?

4. Mole ratio Ratio of moles of one substance to another
Determined from coefficients in the balanced chemical equation
Write all possible mole ratios for the combustion of glucose

5. DO NOW What is the “recipe” that we use in stoichiometry?
What are the quantities expressed in the “recipe”?
In solving stoichiometry problems, what unit equality allows us to convert from one substance to another?
Balanced chemical equation
Moles!
The mole ratio

6. Review of Mole-mole Problem
Hydrogen and oxygen gases react to produce water.
If moles of water is produced, how many moles of oxygen gas must be used?

7. Do NOW!
Write a reaction for the synthesis of ammonia, NH3, from nitrogen and hydrogen gases.
A)If 5.23 moles of ammonia is produced, how many moles of hydrogen reacted?
B)If an excess of nitrogen is reacted with 3.41 g of hydrogen, how many grams of ammonia are produced?

8. How many grams of sulfur trioxide will be produced from the reaction of 45.0 g of sulfur with an excess of oxygen?
MASS-MASS PROBLEM
Mass A ->
Moles A ->
Moles B ->
Mass B
1)Divide by molar mass of A
2)Use mole ratio
3)Multiply by molar mass of B

9. What volume of oxygen gas is required to oxidize 4
What volume of oxygen gas is required to oxidize 4.99 g of NO gas to NO2 gas? (Assume STP)
Type of problem? Volume-Mass
But you are responsible for any…
Moles- mass-particles-volume
So remember your conversion factors

10. Conversion Factors 1 mol = L 1 mol = particles
(molecules, atoms, formula units)
1 mol = g
22.4
6.02 x 1023
(molar mass)
From periodic table

11. Label Given and unit of answers immediately!!!!
Types of problems
Mole –Mole ( 1step)
Mass – Mass ( 3 steps)
Volume- Volume ( 3 steps)
Mass-Volume ( 3steps)
Volume – Mass (3 steps)
Label Given and unit of answers immediately!!!!

12. Convert moles to answer
Balanced chemical equation
Convert given to moles
Use mole ratio
Convert moles to answer

13. Magnesium reacts with hydrochloric acid to produce magnesium chloride and hydrogen gas
If 6.00g of hydrochloric acid reacts with an excess of magnesium, how much magnesium chloride will be produced?
2. If 10.0 grams of magnesium chloride is actually produced, what is the percent yield?

14. Percent = Actual Yield x 100 Yield Theoretical Yield
ACTUALLY/EXPERIMENTALLY made
Percent = Actual Yield x Yield Theoretical Yield
Based on STOICHIOMETRY

15. Why does actual = theoretical, sometimes?
Reaction may not go to completion
Competing reactions may reduce the yield of product
Material may be lost in handling

16. Classic Butter Cookies 2 1/2 cups all-purpose flour 1 cup butter 1/2 cup white sugar 2 eggs 1/2 teaspoon almond extract Bake at 350ºF for 10 minutes. Yields 20 3” cookies
Limiting Excess
Reactant Reactant
If only one egg was available, but as much of the other ingredients as you needed, how many cookies would you make? How much sugar and butter would you use?
If 3 eggs were available, how much flour, butter, and sugar would you need? How many cookies would you make?
If 40 3” cookies were baked, how many cups of flour were used?
If I have 2 eggs, 2 cups of butter, and an excess of all the other ingredients, how many cookies will I make?

17. Iron metal can be produced by reacting iron ore (Fe2O3) with carbon
Iron metal can be produced by reacting iron ore (Fe2O3) with carbon. Carbon monoxide is also produced.
Write a balanced chemical equation for this reaction.
If 50. grams of carbon is reacted with 150 g of iron III oxide, how many grams of iron are produced?

18. Sodium metal and chlorine gas produce sodium chloride.
How many grams of sodium chloride are produced if 15.9 L of chlorine gas, at STP, reacts with an excess of sodium?
What is the percent yield if 58.3 grams of sodium chloride is produced?
In a separate experiment, 25.0 g of sodium reacts with 55.0 g of chlorine, how many grams of sodium chloride are produced? What is the limiting reactant? How much excess reactant remains?