Stoichiometry:Percent Yield and Limiting Reactant

In a lab, a scientist calculate he should produce 12.3 grams of product in his experiment. When he is finished collecting his product it weighs 10.1 grams. What is his percent yield?

• 82%
• 0.82%
• 10.1 %
• 100%

Theoretical yield = 73g
Actual yield = 62g
Calculate the percent yield.

• 1.16%
• 116%
• 85%
• 76%

When reacting Na with Cl₂, we calculated that the theoretical yield should be 13 grams. Our actual yield was 12.5 grams. What is the percent yield?

• 90.4%

• 104%

• 96.15%

• 1.04%

The limiting reactant

• slows the reaction down
• is used up first
• is the reactant that is left over
• controls the speed of the reaction

Use the equation 2 Al + 3 Cl₂ ---> 2 AlCl₃.  If 2 moles of aluminum and 2 moles of chlorine are reacted, identify the limiting reactant. (hint: you have 2 givens)

• AlCl3
• Cl2
• Al

When does a chemical reaction stop?

• When the lab is finished
• When the excess reactant is used up
• When the limiting reactant is used up
• Chemical reactions never stop

What is an excess reactant?

• Substance you end with

• Substance that determines the rate of reaction

• Substance that is not used up completely

• Substance that is used up completely

In order to make a turkey sandwich for your customers, you will need:

2. 2 slices of bread, 23g of Mayo, and 56g of Turkey

You only have 58 slices of bread, 368 g of Mayo and 672g of Turkey

What do you run out of FIRST? (this will be your LIMITING ingredient)

In order to make a turkey sandwich for your customers, you will need:

2. 2 slices of bread, 23g of Mayo, and 56g of Turkey

You only have 58 slices of bread, 368 g of Mayo and 672g of Turkey

How many sandwiches will you be able to make?

• 29

• 16

• 12

• 58