Aluminum and Copper (II) Chloride Lab
Purpose: By reacting aluminum with copper (II) chloride, you will make a reaction.
If you know the grams of aluminum to be reacted you should be able to predict how many grams of a “brown substance” will be produced by using a process known as stoichiometry.
Pre-Lab: Make 15 mL of a 9.92 x 10-1 M solution of Copper (II) Chloride in water. On your data table, record the GRAMS of Copper (II) Chloride you will need to add to the
15 mL of water. Put your solution in your small beaker
1. Obtain a length of aluminum wire from your teacher. Then, coil it up into a loose coil with a little left over as a “handle”. See drawing on front board
2. Find the mass of your Al wire and record on your data table.
3. Find the mass of your small beaker and record it on your data table.
4. Make the solution of Copper (II) chloride as specified in the pre-lab
5. Dip the coil into the Copper (II) Chloride solution and allow it to collect copper for about 1 minute. BE CAREFUL NOT TO BREATHE THE FUMES PRODUCED The wire will be coated with a brown substance (what is that substance? What is the gas produced?)
6. Using your water bottle, squirt a strong stream of water on the coil to remove the brown substance so it falls into the beaker. You want the brown substance to fall into the beaker! WEAR YOUR GOGGLES TO AVOID SPLASHING INTO YOUR EYES. If you cannot get all of the brown substance off of the wire, you might try putting on a rubber glove and “squeezing” the substance off into the beaker. DON’T use your bare hands since the chemicals are poisonous.
7. Dry the Al coil with a paper towel and reweigh it. Record the mass after the reaction on your data table.
8 Decant the blue liquid from your small beaker down the drain. BE CAREFUL NOT TO LET ANY OF THE BROWN SUBSTANCE GO DOWN THE DRAIN.
9. Squirt some water (about 20-30 mL) from your water bottle into your beaker to clean the brown substance. Decant this also into the sink. AGAIN, BE CAREFUL NOT TO LET ANY OF THE BROWN SOLID GO DOWN THE SINK.
10. Put your beaker on one of the hot plates in the fume hood and let it dry out.
11. While your beaker is “drying”, answer the questions posed to you in the question section. Do not copy the questions, but show all work!
12. WHEN THE BEAKER IS COOL, reweigh it and record its mass on the data table.
13. Determine the mass of the brown substance in the beaker and record this on your data table.
Mass of Al wire _________g
Mass of empty small beaker _________g
Grams of Copper (II) Chloride to be added to 15 mL of water ________g
Mass of Al wire after it was dipped in Copper (II) Chloride solution ________g
Mass of Beaker & Brown Substance after heating/drying/cooling _______g
Mass of brown substance by itself ___________g (this is the actual mass of the copper after drying)
Predicted mass of brown substance _______g (from question #8)
1. Write out a balanced equation for this reaction.
2. Is this reaction: Combustion, Single replacement, Double replacement, Synthesis or Decomposition?
3. By looking at your balanced equation and the Coefficients in that equation, how many Aluminum moles are on the Reactant side of the equation?
4. By looking at the balanced equation, how many Copper moles on the Product side of the reaction?
5. Determine how many moles of Aluminum were used in this reaction. To do this, subtract the mass of the Aluminum wire AFTER the reaction from the mass of the original Aluminum wire. Then, convert the grams of aluminum wire used up in this reaction into moles of aluminum.
6. Divide your answer to number 5 by the number of moles of Aluminum you have on the reactant side. (see your answer to #3)
7. Multiply your answer to number 6 by the number of moles of copper you have on the product side. (see your answer to #4)
8. Your answer to number 7 is the number of moles of copper you should expect to create in this experiment. Convert the answer to question #7 to grams of copper and you should have the amount of copper that will come out of this experiment.
9. Subtract your answer from #8 from the grams of “brown substance” you got to see how far off you were.
10. Find the percentage error of your results by using the following formula:
Percentage error = êPredicted grams of brown sub. - Actual grams of brown sub.ê x100
Predicted grams of brown sub.