Chapter 9 Objectives:To understand the molecular and mass information given in a balanced equation.

Chapter 9

Objectives:To understand the molecular and mass information given in a balanced equation.

NOW LET’S GET BACK to…

CO(g) + 2H2(g) CH3OH(l)

9.2 Mole-Mole Relationships

Objectives: To learn to use a balanced equation to determine relationships between moles of reactants and moles of products.

Mole-Ratio:

2H2O 2H2(g) + O2(g)

4H2O 4H2(g) + 2O2(g)

5.8H2O 5.8H2(g) + ?O2(g)

Mole-Ratio:

CH4(g) + 2O2(g) CO2(g) + 2H2O(g)

What number of moles of oxygen gas is

required to react with 7.4 mol of methane?

How many moles of carbon dioxide gas will

be produced by reacting 2.6 mol of oxygen

with excess methane?

Mole-Ratio:

2H2S(g)+3O2(g) 2SO2(g) + 2H2OHow many moles of oxygen gas are required to

react with 5.6 mol of hydrogen sulfide?

How many moles of sulfur dioxide gas will

be produced by reacting 7.3 mol of hydrogen

sulfide with excess oxygen? How many moles of sulfur dioxide gas will be produced by reacting 7.3 mol of oxygen with excess hydrogen sulfide?

Mole-Ratio: HW SC9.1

4FeO(s) + O2(g) 2Fe2O3(s)What number of moles of oxygen gas is

required to react with 2.4 mol of iron(II) oxide?

What number of moles of iron(III) oxide will be

produced by reacting 9.2 mol of iron(II)oxide

with excess oxygen? What number of moles of iron(III) oxide will beproduced by reacting 9.2 mol of oxygen withexcess iron(II) oxide?

9.3 Mass Calculations

Objective: To learn to relate masses of reactants and products in a chemical reaction.

9.3 Mass Calculations

BACK TO THE DELI

2 pieces of bread+3 slices of meat+ 1 cheese

1 sandwich

If each slice of bread weighs ½ of a slice of meat and the total meat = 6 oz, what is the weight of bread necessary for 1 sandwich?

9.3 Mass Calculations

C3H8(g) + O2(g) CO2(g) + H2O(g).

What mass of oxygen is needed to react exactly with 44.1 g of propane?

Step1: Balance the equation

C3H8(g) + 5O2(g) 3CO2(g) + 4H2O(g).

9.3 Mass Calculations

C3H8(g) + 5O2(g) 3CO2(g) + 4H2O(g).

44.1 g ? g O2

? moles ? mol O2

44.1 g C3H8 X 1mol C3H8 = 1.00 mol C3H8

44.09 g C3H8

Step 2

5 mol of O2= 1molC3H8 Step 3

5 mol x 32.0g O2

1 molANSWER

9.3 Mass Calculations

2NaOH(aq)+CO2(g) Na2CO3(g) + H2O(l)

10 g ? g CO2

? moles ? mol CO2

Step 2

Step 3

ANSWER5.5 g CO2

9.3 Mass Calculations

10 g ? g CO2

? moles ? mol CO2

Step 2

Step 3

ANSWER5.5 g CO2

Homework: Self-check exercises 9.2, 9.3, and 9.4

9.5: Mass Calculations-Comparing 2 Reactions

Objectives: To compare the stoichiometry of two reactions

Which is better……………… Baking soda or Milk of Magnesia

9.5: Mass Calculations-Comparing 2 Reactions

How many moles of HCl will react with 1.00 g of each antacid?

Baking soda

NaHCO3(s) + HCl(aq) NaCl(aq)+ H2O + CO2(g)

Milk of MagnesiaMg(OH)2(s) + 2HCl(aq) 2H2O + MgCl2(aq)

Section 9.4: Mass Calculations using Scientific Notation

Objectives: To carry out mass calculations that involve scientific notation.

Stoichiometry: process of using a chemical equation to calculate the relative masses of reactants and products involved in a reaction.

Section 9.4: Mass Calculations using Scientific Notation

1) Divide into 3 or 4 teams p.264

2) Using the equation provided calculate the mass of the substance produced if you use up all of that Top Ten chemical.

Ca3(PO4)2 + H2SO4 H3PO4

N2 + H2 NH3

C2H4 + O2 CO2 + H2OCaCO3 CaO+CO2

NaOH + H3PO4 Na3PO4 + H2OC3H7 + O2 CO2 + H2ONa + Cl2 NaCl

9.6: The Concept of Limiting Reactants

Objective: To understand the concept of limiting reactants

9.6: The Concept of Limiting Reactants

Deli: 20 slices of bread24 slices of meat12 slices of cheese

2 pieces of bread + 3 meat + 1 cheeseHow many sandwiches?What is limiting?NCSSM Distance Learning T.I.G.E.R. - Chemistry page 2#

stoich

Before the Reaction

Before and after the reaction.

Example #2

Before and after the reaction.

Limiting reactant

• NCSSM Distance Learning T.I.G.E.R. - Chemistry page 2#stoich

Section 9.7: Calculations involving a Limiting Reactant

Objectives:To learn to recognize the limiting reactant in a reaction.

To learn to use the limiting reactant to do stoichiometric calculations.

Section 9.7: Calculations involving a Limiting Reactant

Objectives:To learn to recognize the limiting reactant in a reaction.

To learn to use the limiting reactant to do stoichiometric calculations.

9.7 Limiting Reactant

CH4(g) + H2O(g) 3H2(g) + CO(g)

249 g ? g H2O

? moles ? mol H2O

Step 2

Step 3

ANSWER279g H2O

15.5 mol

15.5 mol

9.7 Limiting Reactant

CH4(g) + H2O(g) 3H2(g) + CO(g)

249 g 300 g H2O

? moles ? mol H2O

9.7 Limiting Reactant

CH4(g) + H2O(g) 3H2(g) + CO(g)

249 g 300 g H2O

? moles ? mol H2O

Figure 9.2: A map of the procedure used in Example 9.7.

9.7 Examples

Aluminum reacts with chlorine gas to form aluminum chloride according to the following reaction:

2Al(s) + 3Cl2(g) 2 AlCl3(s)

In a certain experiment, 10.0 g of aluminumIs reacted with 35.0 g of chlorine gas.

What mass of aluminum chloride will be Produced, assuming a complete reaction?

What mass of which reactant is left after the reaction?

43.9 g AlCl3

1.1 g Al(s)

9.8 Percent Yield

Objectives: To learn to calculate actual yield

as a percentage of theoretical yield

Actual yield Theoretical Yield x 100 = percent yield

9.8 Percent Yield

Suppose 6.85x104g of CO(g) reacts with 8.60 kg of H2(g).

Calculate the theoretical yield of methanolIf 3.57x 104 g of CH3OH is produced what is the percent yield?

9.8 Percent YieldUrea is formed by the reaction of ammonia and carbon dioxide:2NH3(g) + CO2(g) CN2H4O(s) + H2O(l)

In a certain experiment 100.0 g of ammonia is reacted with 100.0 g of carbon dioxide, and 120.0 g of urea is produced. Determine the percent yield for this reaction.

88.23 %

The Nuts and Bolts of Chemistry

Do Activity on p. 254

Do this in 3 groups

Answer the questions in number 8.

Turn in the assignment once it’s done.

You have 20 minutes.

We are going to a DELI!

You are making a sandwich.

What do you need?

2 pieces of bread + 3 slices of meat + 1 slice cheese

1 SANDWICH

NOW,HOW MUCH WOULD YOU NEED TO FEED THIS CLASS?