Lab: Moles of Iron and Copper
Introduction:
In this experiment, you will observe the reaction of iron nails with a solution of copper (II) chloride and
determine the ratio of moles iron to moles copper involved in the reaction. This reaction will create an iron
chloride compound with an unknown charge for the iron ion (remember: transition metals can have multiple
charges). Look on your periodic table – because iron can be either a +2 or a +3, the product could be either iron
(II) chloride; FeCl2, or iron (III) chloride; FeCl3. The goal of this experiment is to determine which iron
compound is produced.
Purpose:
1. Determine moles of copper produced in the reaction of iron and copper (II) chloride.
2. Determine moles of iron used in the reaction of iron and copper (II) chloride.
3. Determine the ratio of moles of iron to moles of copper.
4. Determine whether iron (II) chloride or iron (III) chloride is produced in the reaction by using the Fe:Cu
mole ratio.
Materials:
Day 1:
100 mL volumetric flask & stopper
Wash bottle with dH2O
Copper (II) chloride, CuCl2
Electronic balance
Weigh boat
Scoopula
Large test tube
Iron nail
Day 2:
Electronic balance
Crucible tongs
Wash bottle with distilled H2O
Stir rod
Buchner funnel
Pressure tubing
Aspirator
Ring stand
Filter paper
250 mL side arm flask
Procedure (be sure to wear goggles at all times!):
Day 1: The Reaction
1. Make 100 mL of 0.3 M copper (II) chloride solution using the 100 mL volumetric flasks provided for both
groups at each lab table. Be careful with these flasks as they are expensive…you break it, you
buy it! (approx. $25 each)
2. Split the solution (50 mL each for each group at the table) and pout into a large test tube and record the
color of the solution in the data table.
3. Using the labeling tape put your and your partners initials on the tape and then place the tape on the
test tube.
4. Obtain a nail from the teacher. If the nail is not clean, use a piece of steel wool to make the surface
shiny.
5. Mass the nail and record in the data table.
6. Place the nail in the test tube with copper (II) chloride solution and record observations in the data
table.
7. Leave this reaction undisturbed overnight.
8. Clean the volumetric flask and return all other materials.
Day 2: Separating the Products
1. Note any colors present in your test tube and record in your data section.
2. Use crucible tongs to carefully pick up the nail and use distilled water in a wash bottle to rinse off any
remaining copper from the nail into the test tube before removing it completely from the tube. If
necessary, use a stirring rod to scrape any excess copper from the nail back into the test tube. Set the
nail on a paper towel to dry.
3. Set up a vacuum filter apparatus as shown in the figure to the right.
4. Prepare a piece of filter paper for funneling by writing your initials on the edge with pencil.
5. Weigh the piece of filter paper and record in the data table.
6. After hooking up the pressure tubing to the aspirator on the sink faucet, turn the water on and decant
(pour) the liquid out of the test tube so that the solid remains at the bottom of the tube.
7. Once all of the liquid has passed through the funnel, add solid from the test tube into the funnel. (Be
careful not to puncture the filter paper. In case your filter paper should break, hang on to the filter paper
and the filtrate, which is the solution captured in the flask.)
8. After filtering, rinse the solid on the filter paper with a little distilled water from your wash bottle. Repeat
this two or three times, being sure to rinse down the sides of the filter paper as well.
9. After the final washing with water, place the filter paper in the drying oven for 5-10 minutes.
10. After the nail is completely dry, find the mass of the nail and record it in the Data Table. Return the nail
to the teacher.
11. Clean and dry your glassware.
12. When the copper solid on the filter paper is completely dry, find the mass of the filter paper plus the
copper and record it on the data table.
13. Clean and put away the rest of your materials.
Pre-lab Questions: Show all work and round answers to the appropriate number of significant figures. Be sure
to include units!
1. How many grams of copper (II) chloride are needed to make 50 mL of 0.30 M solution?
2. How many moles are present in a sample of 34.0 g of iron metal?
3. How many atoms of iron are present in 2.00 moles of iron?
4. What is a filtrate?
5. Why are repeated washings of the solid in the filter paper necessary in the filtration process?
6. In the reaction between iron and copper (II) chloride, copper metal and an iron chloride is produced.
There are two possible oxidation numbers for iron in the product, +2 or +3.
a. Write the balanced reaction for this experiment, assuming that iron is a
+2
in the product.
b. Write the balanced reaction for this experiment, assuming that iron is a
+3
in the product.
7. What type of reaction is occurring between iron and copper (II) chloride?
Data:
Day 1
Mass (g)
Day 1 Colors
Mass of CuCl2
CuCl2 solution:
Mass of iron nail
Nail:
Solution + Nail:
Day 2
Mass of dry filter paper
Mass of dry iron nail
Mass (g)
Day 2 Colors
Solution:
Mass of dry filter paper and copper
Nail:
Mass of copper produced
Wet Cu:
Mass of iron consumed
Dry Cu:
Calculations: Show ALL work and round answers to the appropriate number of significant figures. Be sure to
include units!
1.
Find the following masses by the appropriate subtractions.
a. Mass of iron metal used up in the reaction
b. Mass of copper metal produced
2.
Find the number of moles of the following:
a. Moles of iron used up
b. Moles of copper produced
3. Calculate the whole number ratio of moles of copper produced to moles of iron used.
(Hint: divide each number by the smallest number of moles)
Analysis Questions:
1. Think about the colors you observed. Was there any evidence that some of the copper (II) chloride was
leftover when the reaction had finished? Explain.
2. Which reactant (iron or copper (II) chloride) was left over at the end of this reaction? Explain your
reasoning.
3. Based on the mole ratio you calculated in this experiment, what is the correct balanced equation for this
reaction? Choose from one of the two reactions you generated in the pre-lab and write it below.
4. Calculate the percent composition of iron in the iron chloride, based on your results.