Classic Butter Cookies 2 1/2 cups all-purpose flour 1 cup butter 1/2 cup white sugar 2 eggs 1/2 teaspoon almond extractBake at 350ºF for 10 minutes.Yields 20 3” cookies1. 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?

Stoichiometry

The study of the quantitative, or measurable, relationships that exist in chemical formulas and

chemical reactions.

Write a reaction for the combustion of glucose, C6H12O6

1.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?

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

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

Review of Mole-mole Problem

• Hydrogen and oxygen gases react to produce water.

• If 59.84 moles of water is produced, how many moles of oxygen gas must be used?

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?

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 B1)Divide

by molar

mass of A

2)Use mole ratio

3)Multiply by molar

mass of B

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-volumeSo remember your conversion factors

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

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!!!!

1. Balanced chemical equation

2. Convert given to moles

3. Use mole ratio

4. Convert moles to answer

1. 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?

Magnesium reacts with hydrochloric acid to produce magnesium chloride and hydrogen gas

Percent = Actual Yield x 100 Yield Theoretical Yield

ACTUALLY/EXPERIMENTALLY made

Based on STOICHIOMETRY

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

Classic Butter Cookies 2 1/2 cups all-purpose flour 1 cup butter 1/2 cup white sugar 2 eggs 1/2 teaspoon almond extractBake at 350ºF for 10 minutes.Yields 20 3” cookies

If I have 2 eggs, 2 cups of butter, and an excess of all the other ingredients, how many cookies will I make?

Limiting ExcessReactant Reactant

Iron metal can be produced by reacting iron ore (Fe2O3) with carbon. Carbon

monoxide is also produced.

1.Write a balanced chemical equation for this reaction.

2.If 50. grams of carbon is reacted with 150 g of iron III oxide, how many grams of iron are produced?

Sodium metal and chlorine gas produce sodium chloride.

1. How many grams of sodium chloride are produced if 15.9 L of chlorine gas, at STP, reacts with an excess of sodium?

2. What is the percent yield if 58.3 grams of sodium chloride is produced?

3. 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?