Stoichiometry w/Percent Yield and Limiting Reagent

Admit SlipWrite the action required for each arrow of the diagram.

AgendaAdmit SlipNotesClasswork

Product: Notes and ClassworkHomework : Problems #1-3

Today’s Objectives• Students will be able to:• Convert the mass or moles of one substance

to the mass or moles of another substance in a balanced chemical reaction ( stoichiometry)

• Calculate percent yield • Calculate the limited reagent

Percent Yield and Limited Reagent 4/22/13Often in a chemical reaction, you do NOT make

as much as you should make according to stoichiometry.For every percent yield problem, you will calculate how much you SHOULD make of a product (the theoretical amount)Also, you will be given an amount that is ACTUALLY made of that product.You compare these two amounts through this equation.Percent = Actual Amount x 100% Yield Theoretical Amount

Percent Yield Example• 4 C3H5O + 15 O2 12 CO2 + 10 H2O

• In the lab, you only produce 10 mol of CO2 from 18 mol of O2. What is the percent yield?

• a) How many mol CO2 should you make?

• b) What is the percent yield?

Limited Reagent/ReactantA limited reactant question is the same idea as the following question: You have 15 chocolate chips and 20 cups of sugar. Which one will cause you to make less cookies?

For a limited reagent question, you use the amounts of reactants given and figure out which reactant will give you less products. It doesn’t matter which product you pick, you should get the same answer either way.

Limited Reactant ExampleC3H8 + 5 O2 3 CO2 + 4 H2O

• Given 10 mol of C3H8 and 30 mol of O2, which is the limited reactant?•Determine how much these amounts would make of one of the products, (ex. CO2). Whichever reactant makes less (CO2) is the limited reactant.

ClassworkC5H12 + 8 O2 5 CO2 + 6 H2Opentane oxygen carbon dioxide water

1. How many moles of pentane would be needed to form 8 moles of water ?

8 mol H2O *

C5H12 + 8 O2 5 CO2 + 6 H2Opentane oxygen carbon dioxide water

2. Given 18 moles of O2, how many moles of CO2 will be formed?

C5H12 + 8 O2 5 CO2 + 6 H2Opentane oxygen carbon dioxide water

3. Given 200 g of C5H12 , how many moles of CO2 will be formed?

C5H12 + 8 O2 5 CO2 + 6 H2Opentane oxygen carbon dioxide water

4. Given 1.6 moles of C5H12, how many grams of H2O will be formed?

C5H12 + 8 O2 5 CO2 + 6 H2O

5. How many grams of O2 is necessary to form 106 g of CO2 ?

C5H12 + 8 O2 5 CO2 + 6 H2O

6. How many grams of water will be formed from 250 g of C5H12 ?

8. The percent yield is

___________________________________ x 100%

C5H12 + 8 O2 5 CO2 + 6 H2O

9. If you produce 7 moles of H2O from 20 moles of O2 , what is the percent yield?

C5H12 + 8 O2 5 CO2 + 6 H2O

10. If you produce 16 moles of CO2 from 4 moles of C5H12, what is the percent yield?

C5H12 + 8 O2 5 CO2 + 6 H2O

10. If you produce 16 moles of CO2 from 4 moles of C5H12, what is the percent yield?

11.In your own words, what is the limiting reactant/reagent?

 It is the reactant that _____________________________

______________________________________

 

C5H12 + 8 O2 5 CO2 + 6 H2O

12. Given 4 mol of C5H12 and 27 mol of O2 , which is the limiting reagent?

C5H12 + 8 O2 5 CO2 + 6 H2O

13. Given 210 g of C5H12 and 128 g of O2, which is the limiting reagent?

C5H12 + 8 O2 5 CO2 + 6 H2O

Exit SlipSolve and explain the following problem in words!How many grams of O2 would you need to form 165 g of C5H12 ?