DO NOW: 4/27

Pick up knowledge organizer and objectives

Attach objectives in notebook Take out labs from Monday &

Tuesday

UNIT 8 - STOICHIOMETRYReaction Stoichiometry

STOICHIOMETRY-AN ANALOGY WITH CAKE(YOU DO NOT NEED TO COPY THIS

1 cake mix + 3 eggs + 1 cup water 1 cake

We can create ratios out of this: These can be used as conversion factors1 cake mix-to 1 cake 3 eggs-to-1 cake 1 cup water-to-3

eggs

1 cake mix 3 eggs 1 cup water

1 cake 1 cake 3 eggs

(remember you can flip these conversion factors when necessary)

WHERE DO WE USE STOICHIOMETRY?

To determine: how much of the other reactants are

needed how much of each product should be

produced limiting reactants

1 CAKE MIX + 3 EGGS + 1 CUP WATER 1 CAKE

If you have 6 eggs how many cakes can you make?

If you add 4 cups of water how many cake mixes will you need?

If you have 2 cake mixes, 3 cups of water and 5 eggs, how many cakes can you make? Why not more?

6 eggs x 1 cake = 2 cakes 3 eggs

4 cups water x 1 cake mix = 4 cake mixes 1 cup water

1 and 2/3 cake. You are limited by the number of eggs you have. Only have enough for 1 2/3 cakes.

MOLE RATIO IN REACTIONS

2 H2 + O2 2 H2O

Coefficients can represent moles in balanced reactions.

2 moles of hydrogen burn with 1 mole of oxygen to form 2 moles

of water.

MOLE RATIO 2 H2 + O2 2 H2O

Possible mole ratios/ conversion factors: 2 H2-to-1 O2 2 mol H2

1 mol O2

2 H2O-to-2H2 2 mol H2O

2 mol H2

2 H2O-to-1 O2 2 mol H2O

1 mol O2 3 others exist

1) Balance this equation:

HgO Hg + O2

2) What is the mole ratio between HgO and O2?

3) If you start with 10 moles of HgO, how many moles of O2 would you make?

2 2

2 mol HgO1 mol O2

10 mol HgO X 1 mol O2 = 5 mol O2

2 mol HgO

2HgO 2Hg + O2

1) What is the mole ratio between HgO and Hg?

2) If you start with 10 moles of HgO, how many moles of Hg would you make?

2 mol HgO2 mol Hg

10 mol HgO X 2 mol Hg = 10 mol Hg

2 mol HgO

2HgO 2Hg + O2

If you start with 100 g of HgO how many moles of O2 would be formed in the reaction?

100 g HgO X 1 mol HgO X 1 mol O2 = 0.23 mol O2

216.59 g HgO 2 mol HgO

DO NOW: 3/28

2HgO 2Hg + O2

If you start with 20.7 g of HgO how many moles of Hg would be formed in the reaction?

What is the mass of HgO you need to form 10.0 grams of O2 From this reaction?

HgO Hg + O2

MORE PRACTICE WITH MOLE RATIO

2 2

10.0 g O2 X 1 mol O2 X 2 mol HgO X 216.59 g HgO =135.4 g HgO

32 g O2 1 mol O2 1 mol HgO

ALL CLASS PRACTICE: H2SO4 + 2NaOH Na2SO4 + 2H2O

How many moles of NaOH do you need to react with 1.00 mole of H2SO4?

How many moles of NaOH do you need to react with 32.7 moles H2SO4?

32.7 mol H2SO4 X 2 mol NaOH = 65.4 mol NaOH

1 mol H2SO4

1.00 mol H2SO4 X 2 mol NaOH = 2.00 mol NaOH

1 mol H2SO4

ALL CLASS PRACTICE: H2SO4 + 2NaOH Na2SO4 + 2H2O

How many moles of H2SO4 do you need to react with 20.0 g NaOH?

How many grams of Na2SO4 will be produced if 27.6 g NaOH is reacted with excess H2SO4?

2O.0 g NaOH X 1 mol NaOH X 1 mol H2SO4 = 0.250 mol H2SO4

39.99 g NaOH 2 mol NaOH

27.6 g NaOH X 1 mol NaOH X 1 mol Na2SO4 X 142.04 g Na2SO4 = 49.0 g Na2SO4

39.99 g NaOH 2mol NaOH 1 mol Na2SO4