Molar Ratios

WEDNESDAY: mole ratios

▪ Phones up by the bell!
▪ Friday 1/6 Unit 7 Quiz 1

▪ Thursday 1/12 Unit 7 Quiz 2
▪ Thursday 1/19 Unit 7 test

ANNOUNCEMENTS/REMINDERS:

Bellwork

PPT- mole ratios

AGENDA:

Bellwork:

1. On GC

Mole-Mole Relationship

• Uses a BALANCED chemical equation to predict the moles of

products that a given number of moles of reactants will yield

• Coefficients in an equation can represent:

– Relative # moles
– Relative # molecules
– Relative volumes
– Does NOT represent grams (mass)

Ex.

C3H8(g) + 5O2(g) 🡪 3CO2(g) + 4H2O(g)

Remember that this means:

1 mole C3H8(g)and 5 moles O2(g) combine to form 3 moles CO2(g) and 4 moles H2O(g)

Multiple Choice

Mole ratios are obtained from the

• balanced chemical equation

• periodic table

• molar mass

CHOCOLATE CHIP COOKIES!!

1 cup butter
.5 cup white sugar
1 cup packed brown sugar
1 teaspoon vanilla extract
2 eggs
2.5 cups all-purpose flour
1 teaspoon baking soda
1 teaspoon salt
2 cups semisweet chocolate chips
Makes 3 dozen

How many eggs are needed to make 3 dozen cookies?

How much butter is needed for 4 cups of chocolate chips?

How many eggs would we need to make 9 dozen cookies?

How much brown sugar would I need if I had 2 cups white sugar?

How much butter is needed for 3 cups of chocolate chips?

CHEMISTRY RECIPES

•Looking at a reaction tells us how much of
something you need to react with something
else to get a product (like the cookie recipe)

•Be sure you have a balanced reaction before
you start!

• Based on this balanced equation:

What number of moles of CO2(g) will be produced from

1.8 mol C3H8(g) reacting with excess O2(g)?

C3H8(g) + 5O2(g) 🡪 3CO2(g) + 4H2O(g)

• Based on this balanced equation:

What number of moles of CO2(g) will be produced from

1.8 mol C3H8(g) reacting with excess O2(g)?

C3H8(g) + 5O2(g) 🡪 3CO2(g) + 4H2O(g)

• Solution:

1.8 mol C3H8(g) x 3 mol CO2(g) = 5.4 mol CO2(g)

1 mol C3H8(g)

1

2

3

4

Ellie

jude

Jake K

Anna

Dylan

Banks

Taylor

Cassidy

Will Jones

Emma

Will RameyMason

Dallas

Garrett

Sarah

Owen

Jake S

Trinity

Bevan

Coleman

Tez

Hartford

Ella

Simi

Multiple Choice

True or False. You must convert grams to moles to do stoichiometry.

• True

• False

Multiple Choice

2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O

Ethane (C₂H₆) combusts in the above reaction. What is the mole ratio of carbon dioxide to water?

Multiple Choice

What is the mole ratio of H₂O to H₃PO₄ in the following chemical equation?   P₄O₁₀ + 6 H₂O --> 4 H₃PO₄ 

• 6:4

• 4:6

• 1:3

• 3:1