Video 803 lab answers and quiz answers

Check your answers to the video lab below.

In this lab, iron and copper (II) sulfate react according to the following BALANCED equation.

Fe + CuSO4 Cu + FeSO4

mass of copper (II) sulfate = 12.50 g

mass of iron filings = 2.24 g

mass of filter paper and Cu = 3.44 g

mass of filter paper = 0.93 g

mass of Cu = 2.51 g

color of decanted liquid = blue

Conclusions:

Hover over the word Answer to check your solutions.

1. Calculate the number of moles of iron used in the reaction.

Answer

? mol Fe = 2.24 g Fe (1 mol Fe / 55.8 g Fe) = 0.0401 mol Fe

 

2. Calculate the number of moles of copper (II) sulfate used in the reaction.

Answer

? mol CuSO4 = 12.50 g CuSO4 (1 mol CuSO4 / 159.6 g CuSO4) = 0.07832 mol CuSO4

 

3. Using your answer to number 1 and the balanced equation, calculate the theoretical yield of copper produced in this lab.

Answer

? mol Cu = 0.0401 mol Fe (1 mol Cu / 1 mol Fe) x (63.5 g Cu / 1 mol Cu) = 2.55 g Cu

 

4. Using your answer to number 2 and the balanced equation, calculate the theoretical yield of copper produced in this lab.

Answer

? g Cu = 0.07832 mol CuSO4 (1 mol Cu / 1 mol CuSO4) x (63.5 g Cu / 1 mol Cu) = 4.97 g Cu

 

5. Based on your answers to numbers 3 and 4, which reactant is your limiting reactant?

Answer

iron

 

Which reactant is your excess reactant?

Answer

copper (II) sulfate

 

What is the theoretical yield of copper produced in this lab?

Answer

2.55 g Cu

 

6. In this experiment, when the copper (II) sulfate dissolved, the water turned a blue color. After the reaction was over, was the decanted liquid colorless or did some of the color remain?

Answer

color remained

 

Would that indicate that all of the copper (II) sulfate was used up in the experiment or that some of the copper (II) sulfate was unused?

Answer

some was unused

 

Based on these observations, which reactant is your limiting reactant?

Answer

iron

 

Which reactant is your excess reactant?

Answer

Copper (II) sulfate

 

7. Use your answer to number 5 and the actual amount of copper produced in the experiment from your data table to calculate the % yield of copper in the experiment.

Answer

(2.51 g / 2.55 g) x 100% = 98.4% yield of copper, Cu

 

Video Quiz Answers

An equation is said to be balanced if it follows the Law of Conservation of Mass.
False
True
All stoichiometry problems involve starting with information about one substance and finding information about a different substance. What is always involved in “making the switch?” (choose all correct answers)
the mole ration
the balanced equation
subscripts from the formulas
What is the reactant called that is completely used up in a chemical reaction?
limiting reactant
excess reactant
What is the reactant called that remains after the reaction is complete?
excessive reactant
limiting reactant

How many moles of water will be produced if two moles of Hydrogen gas are mixed with two moles of oxygen gas? 2H2 + O2 → 2H2O

Answer

2 mol H2

What is the limiting reactant in the previous question?
hydrogen
oxygen

How many moles of the excess reactant from number 3 will be left over after the reaction is complete?
2H2 + O2 → 2H2O

Answer

1 mol

 

 

 

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