Question

Objective

Find the ratio of moles of reactant to moles of a product for the reaction below. Compare mass and mole amounts of reactants to determine the amount of products that can be/are made.

Background

Chemical reactions are represented by balanced chemical equations. Proper interpretation of an equation provides a great deal of information about the reaction it represents and about the substances involved in the reaction. For example, the coefficients in a balanced equation indicate the number of moles of each substance. Thus, the ratio of moles of a substance to moles of any other substance in the reaction can be determined at a glance.

In this experiment, iron metal will be added to an aqueous solution of copper(II) sulfate. A single replacement reaction will occur, the products being iron(II) sulfate and copper metal. The balanced equation for the reaction is:

Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)

The limiting reactant is the reactant that is used up completely in the reaction. It “limits” the amount of product that can be made. As the equation shows, the number of moles of copper produced should be equal to the number of moles of limiting reactant, since all mole ratios are 1 to 1.

Procedure

Make sure to record your observations carefully throughout the experiment. Record all masses on the same balance and tare any items you will need the mass of in calculations.

Precisely weigh about 8.0 grams of CuSO4 • 5H2O crystals into a 100 mL (or greater) beaker. Add 50.0 mL of DI water and heat with a Bunsen Burner to less than boiling. Due to the reactive nature of elemental iron, quickly (but not hurriedly) weigh about 1.2 grams of iron fillings and add in small portions to the heated copper solution while stirring with a glass stirring rod. After the addition is complete, allow the solution to sit for 10 minutes before proceeding.

Wash the solid in the beaker with 3 portions of 5 – 10 mL of DI water; decant the wash water off the solids. Using a gravity filtration apparatus, collect all solids on a piece of filter paper, rinse gently with DI water, and place the filter paper in the drying oven. After drying record the mass of the substance on the filter paper for your calculations.

Questions

1) What is the theoretical yield of product from the reactant amounts you used?

2) Which reactant was limiting? That is, which product limits the amount of product that is formed? Is there any indication that your calculation matches observation?

3) How many grams of excess reactant should there be left?

4) What is the yield of product made?

5) What is the percent yield of product made?

6) Why do you think your yield was/was not 100%?

Here is the video for the weights

https://www.youtube.com/watch?v=acsveQ1Q7oA&feature=emb_title