Chemistry (4/25)

Objectives: Complete Chemical Quantities ExamPerform Hydrate Lab

Homework:Answer post lab questions.

Chemistry (4/26)Objectives: Complete Hydrate Lab and post-lab questions.

Homework:Complete post lab questions. Due Monday

Chemistry (4/29)Objectives: • Complete post-lab questions for Hydrate Lab.

• Identify and apply stoichiometry with substances in a chemical equation.

Homework:Stoichiometry Problems

Hydrate Lab Cu(SO4) . H2O ----> Cu(SO4) + H2O

Post-Lab questions:Use the equation above to help answer the following

questions:1. What was the hydrate salt in this experiment?2. What was the anhydrous salt in this experiment?3. What was the difference between the hydrated salt

and the anhydrous salt in this experiment?4. Was this a physical or chemical reaction? Validate your

answer with data from your lab.

Hydrate Lab Cu(SO4) . H2O ----> Cu(SO4) + H2O

Copper Sulfate Hydrate

What is Stoichiometry?

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Stoichiometry N2 + 3H2 ----------> 2NH3

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(NH3 ) (N2)

Chemistry (5/1)Infinite Campus Update:• Chemical Quantities Exam (37pts)• Hydrate Lab (10pts.)

Objectives: • Identify and apply stoichiometry with substances in a

balanced chemical equation.

Homework:Stoichiometry Problems

Bell Ringer 1. Calculate the percent composition of water in this

hydrate: Mg(SO4) . 7H2O (Epsom Salt)

2. What is stoichiometry?

3. N2H4 + O2 -----> N2 + H2O

a. Balance the chemical equation.

b. How many moles of rocket fuel (N2H4) are needed to produce 8 moles of N2?

Bell Ringer 1. Calculate the percent composition of water in this

hydrate: Mg(SO4) . 7H2O (Epsom Salt)

2.What is stoichiometry?3. N2H4 + O2 -----> N2 + H2Oa. Balance the chemical equation.b. How many moles of rocket fuel (N2H4) are needed to

produce 8 moles of N2?

Bell Ringer 1. Calculate the percent composition of water in this

hydrate: Mg(SO4) . 7H2O (Epsom Salt)

2. What is stoichiometry?

3. N2H4 + O2 -----> N2 + H2O

a. Balance the chemical equation.b. How many moles of rocket fuel (N2H4) are needed to

produce 8 moles of N2?

Stoichiometry N2 + 3H2 ----------> 2NH3

Stoichiometry: •Converting between substances in a balanced chemical equation using mole conversions.

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(NH3) (N2)

Stoichiometry H2O ----------> H2 + O2

1. What type of reaction is this?2. Balance the chemical equation if needed. 3. If you start with 100 moles of H2O how many moles of H2

would be produced?

3. If you want to produce 3.8moles of O2, how much H2O will you need to start with?

Chemistry (5/2)

Objectives: • Identify and apply stoichiometry with substances in

a balanced chemical equation.

Homework:Stoichiometry Problems

Stoichiometry: Mole to Mole

Stoichiometry N2 + 3H2 ----------> 2NH3

Stoichiometry: •Converting between substances in a balanced chemical equation using mole conversions.

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Stoichiometry Problems

N2H4 + O2 -----> N2 + 2 H2O

• If 13.8 grams of water were produced how much rocket fuel (N2H4) in grams would have been used up?

Chemistry (5/6)

Objectives: • Identify and apply stoichiometry with substances in a

balanced chemical equation.

Homework:Stoichiometry Problems (due Wed.)Gas Laws Graphing Assignment (due Wed.)

Quiz: Wednesday (Stoichiometry conversions: mole to mole or grams to grams.)

Stoichiometry N2 + 3H2 ----------> 2NH3

Stoichiometry: •Converting between substances in a balanced chemical equation using mole conversions.

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Stoichiometery Problems

Pre-AP Chemistry (4/25)Objectives: •Apply stoichiometry conversions with substances in chemical equations. •Identify and apply limiting reactants in chemical reactions. •Calculate StoichiometryHomework: •Stoichiometry and Limiting Reactants

Stoichiometry N2 + 3H2 ----------> 2NH3

Stoichiometry: •Converting between substances in a balanced chemical equation using mole conversions.

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Stoichiometry: Limiting Reactants• Limiting Reactant:

• Excess Reactant:

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Stoichiometry: Limiting Reactants• Limiting Reactant: completely consumed

• Excess Reactant: partially consumed

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Stoichiometry: Limiting Reactant HCl + Mg -------> MgCl2 + H2

1. What type of reactions is this?2. Balance equation if needed.3. If 6.8 moles of Mg react with 7.5 moles of HCl which is

considered the limiting reactant? excess reactant?Reactants Have (moles) Need (moles)

Stoichiometry: Limiting Reactant 2HCl + Mg -------> MgCl2 + H2

1.If 6.8 moles of Mg react with 7.5 moles of HCl how many moles of MgCl2 can be produced?

Reactants Have (moles) Need (moles)

HCl (limited) 7.5 mol 13.6

Mg (excess) 6.8 mol 3.75

Pre-AP Chemistry 4/26

Objectives: • Identify and apply limiting reactants in

stoichiometric calculations. • Distinguish between theoretical and actual

yield.• Calculate % yield. Homework: Limiting and % Yield worksheets.

Theoretical vs. Actual Yield of Products • Theoretical yield: maximum amount that can be

produced according to the limiting reactant. (calculated yield)

• Actual yield: actual amount produced in the lab.

Stoichiometry: Limiting Reactant4. Limiting Reactant: Al Theoretical Yield of AlCl3: 3.0 moles

5. Limiting Reactant: C2H4

Theoretical yield of H2O: 5.4 moles

6. Limiting Reactant: N2

Theoretical yield of NH3: 34 g

Limiting Reactant

Stoichiometry: Percent Yield4. Theoretical Yield of AlCl3: 3.0 moles

Actual yield from lab of AlCl3: 2.8 mole

% Yield of AlCl3 :

5. Theoretical yield of H2O: 5.4 moles

Actual yield from lab of H2O: 4.9 moles

% Yield of H2O:

6. Theoretical yield of NH3: 34 g

Actual yield from lab of NH3: 31.5 g

% yield of NH3:

Stoichiometry: Percent Yield % Yield of Product: Accuracy of product formation in the lab.

% Yield of product: actual yield x 100 theoretical yield Actual yield: actual amount formed in lab

Theoretical yield: maximum amount that can be produced according to the limiting reactant. (calculated yield)

Pre-AP Chemistry (4/29)Objectives:• Identify and apply limiting reactants in a chemical

equation. • Calculate percent yield of products in a chemical

equation. • Identify what molarity is. Homework:• Complete Limiting and % Yield worksheet. • Read over lab and complete hypothesis section.

*Quiz: Wednesday over stoichiometry, limiting reactants, and percent yield of products.

Bell Ringer: Limiting Reactants and % Yield C2H2 + O2 --- CO2 + H2O

1. Balance the equation if needed.2.If 2.40 moles of C2H2 reacts with 7.40 moles of

O2 how many grams of water can be produced?

a. What is the limiting reactant?b.Use limiting reactant to calculate theoretical

yield of H2O in grams.

c. If the actual yield of H2O in the lab was 40.1 grams, calculate what the % yield of H2O would be.

Stoichiometry

Objectives:• Identify what stoichiometry is in chemistry.• Apply stoichiometry calculations in chemical

reactions. • Identify and apply limiting reagents in

chemical reactions.• Calculate % yield of products in a chemical

reaction.