Experience 3: Limiting Reactant and Percent Yield

Which option below has the correct order of steps to complete a stoichiometric calculation to determine percent yield?

Write a balanced equation, determine the limiting reactant, calculate the theoretical yield, calculate the percent yield

Write a balanced equation, determine the excess reactant, calculate the theoretical yield, calculate the percent yield

Determine the excess reactant, write a balanced equation, calculate the theoretical yield, calculate the percent yield

Calculate the percent yield, determine the limiting reactant, write a balanced equation, calculate the theoretical yield

A) Write a balanced equation, determine the limiting reactant, calculate the theoretical yield, calculate the percent yield

A welder has 1.873 × 10^2 g Fe2O3 and 94.51 g Al in his welding kit. Which reactant will he run out of first?

A welder has 1.873 × 10^2 g Fe2O3 and 94.51 g Al in his welding kit. Which reactant will he run out of first?

Fe2O3

How many grams of aluminum oxide are produced in the reaction?

119.6 g

Hydrogen gas can be produced by the reaction of magnesium metal with hydrochloric acid by the reaction below.

Mg + 2HCl → MgCl2 + H2

If 4.00 g of Mg is reacted with 3.20 g of HCl, what is the limiting reactant?

HCI

Which reactant is the excess reactant?

Mg

How many grams of magnesium chloride is produced in the reaction?

4.18 g MgCl2

In the reaction below, 1.000 × 103 g LiOH is combined with 8.80 × 102 g CO2. The reaction produces 3.25 × 102 g H2O in an experiment.

CO2 + 2LiOH → Li2CO3 + H2O

What is the limiting reactant in this reaction?

Co2

What is the theoretical yield of water in this test reaction?

360. g water

What is the percent yield of the reaction? Type in the answer using 3 significant figures.

__%

90.3

Part 1

Part 1

If a substance is the limiting reactant, then...

because...

it will be fully consumed by the time the reaction completes...

it is the reactant that reacts completely and the reaction cannot proceed further.

However, impurities and errors can occur easily. Suppose that only 2.86 g of copper iterm-3s produced. What is the percent yield of the reaction?

81%

When you perform this reaction, what substances could remain at the end of the reaction? Check all that apply.

~excess reactant aqueous copper chloride

~excess reactant aluminum

~oxygen

~product solid copper

~carbon dioxide

~product aqueous aluminum chloride

~water

*excess reactant aqueous copper chloride

*excess reactant aluminum

*product solid copper

*product aqueous aluminum chloride

*water

Part 2

Part 2

If aluminum is the limiting reactant, ------- noneallof it will still be visible after the reaction completes.

If CuCl2 is the limiting reactant, ------- somenoneall of the aluminum will still be visible.

none

some

In Trial 1, you will use 0.50 g of aluminum, and in Trial 2, you will use only 0.25 g. Why will you vary the amount of aluminum?

changing the amount of reactants affects affects the amount of products made in a chemical reaction.

Why might the amount of copper produced be less than 100% of the expected amount? Check all possible reasons.

There are impurities in the substances.

The reaction might not go to completion.

The amount of one of the reactants might be measured incorrectly.

The expected amount might be based on measurements with error.

How can you improve the percent yield of copper in this lab? Check all possible strategies that will help you do so.

Measure reactants precisely.

Stir to help the reaction take place.

Wait patiently until the reaction completes.

Make sure to recover as much copper as possible.

The reason a filter system is used in thisexperiment is to separate and collectX the aqueous aluminum chloridethe remaining copper chlorideX the solid aluminum----- the solid copperall of the products in the reaction.

the solid copper

Put the list in chronological order (1-5).

Allow the solid/liquid mixture to drain through the filter.

Use water to rinse the filter paper containing the mixture.

Place the filter paper in the funnel, then place the funnel in the Erlenmeyer flask.

Weigh the dried filter paper and copper.

Weigh and fold the filter paper.

1. Weigh and fold the filter paper.

2. Place the filter paper in the funnel, then place the funnel in the Erlenmeyer flask.

3. Allow the solid/liquid mixture to drain through the filter.

4. Use water to rinse the filter paper containing the mixture.

5. Weigh the dried filter paper and copper.

One of the product chemicals is aluminum chloride, which is an eye and skin irritant that can cause chemical burns. What will prevent you from coming into contact with this hazard? Check all that apply.

a stir bar

filters

chemical-resistant gloves

a lab coat

fire blankets

safety glasses

chemical-resistant gloves

a lab coat

safety glasses