Chris Halen
Mr. Kark - Chemistry
February 10, 2013
Quantitative Analysis
Purpose:
To measure the number of moles of iron consumed and copper produced in the reaction of iron with
aqueous copper (II) chloride.
To write a balanced chemical equation for the reaction.
Procedure:
As you perform the experiment, record your data in Table 12.1 and your observations in Table 12.2.
Day 1
1) Using a glass-marking pencil label a clean, dry 250-mL beaker with your name. Determine the
mass of the beaker to the nearest 0.01 g, and record the measurement in Table 12.1.
2) Add 50 mL of copper (II) chloride solution to the beaker.
3) Clean two iron nails with steel wool, to remove any rust or protective coating. Determine the
combined mass of the nails to the nearest 0.01 g and record the measurement.
4) Slide the nails carefully into the solution of copper (II) chloride. Let the beaker stand
undisturbed for at least 20 minutes. Record any evidence of a chemical reaction in Table 12.2.
5) Using crucible tongs, remove one of the nails from the reaction solution. Hold the nail over the
reaction beaker. Rinse the adherent reaction product off the nail and into the beaker, using a jet
of distilled water from a wash bottle, as shown in Figure 12.1. Repeat this procedure for the
second nail.
6) Allow the nails to dry on a paper towel in a safe place. (You will re-measure their mass later.)
7) Carefully decant the liquid portion of the reaction solution into another 250-mL beaker, as
shown in Figure 12.2. Leave the solid reaction product in the original beaker. Dispose of the
decanted solution by pouring it into the sink.
8) Use 25 mL of distilled water to wash the reaction product contained in the beaker. Decant the
wash water into the collection container. Repeat the washing and decanting procedures two
more times, being careful to avoid losing any reaction product. Pour the contents of the
collection container into the sink.
9) Give the reaction beaker containing the solid product to your teacher to be dried.
Day 2
10) Determine the combined mass of the dry nails to the nearest 0.01 g and record the
measurement.
11) Determine the mass of the beaker and the dry reaction product to the nearest 0.01 g and record
the measurement. When you are finished, dispose of the nails and the solid product in a waste
container.
Halen 2
Data Table:
Table 12.1 Mass Determinations
Items
Mass (g)
Empty Dry Beaker
82.65
Iron Nails (before reaction)
22.072
Iron Nails (after reaction)
20.659
Beaker and Dry Product
84.06
Calculations:
1) Mass of Fe Reacted
22.072g – 20.659 = 1.413g
2) Moles of Fe Reacted
1.413g (1 mol / 55.847g) = .02530 mol
3) Mass of Cu Formed
84.06g – 82.65g = 1.41 g
4) Moles of Cu Formed
1.41g (1mol / 63.55g) = .0222 mol
5) Fe(s) + CuCl2(aq)  FeCl2 (aq) + Cu(s)
Calculation mol Fe: mol Cu
.02530 : .0222
1.14 : 1.00
Halen 3
6) % Error = ((Accepted – Experimental) / 1.000mol) x 100
(1.14 – 1.00) / 1.00
.14 x 100 = 14%
7) Calculating Mass of Cu That Should Have Formed
1.413g Fe (1mol / 55.847g) (1mol Cu/ 1 mol Fe) (63.546g Cu / 1 mol Cu) = 1.608g
8) %Error = ((Accepted – Experimental) / 1.000mol) x 100
(1.608 – 1.41) / 1.608
(.20 / 1.608) x 100 = 12%
9) % Yield = (Actual / Theoretical) x 100
(1.41 / 1.608) x 100 = 87.7 %
Table of Calculations:
Description
Results
Fe Reacted (g)
1.413
Fe Reacted (mol)
.02530
Cu Formed (g)
1.41
Cu Formed (mol
.0222
Mol Fe : Mol Cu
1.41 : 1.00
Error Using Mols (%)
14
Theoretical Amount of Cu Produced (g)
1.608
Error Using Mass (%)
12
Yield (%)
87.7
Halen 4
Discussion of Results:
In the single replacement reaction of Fe and Copper (II) chloride, Fe replaces Cu2+ ions to produce Iron
(II) chloride and a copper precipitate. Theoretically, 1.608g of Cu should have formed in the reaction.
1.41g of Cu was formed which was lower than expected and caused a 12% error. There were multiple
possible places in the procedure where errors could have been committed. One possibility was pouring
Cu out of the beaker when cleaning it of other chemicals. To fix this, the Cu must be allowed to settle
after squirting it with water before pouring it out. Another contributing factor to this was scraping the
Cu off the nail into the beaker. If Cu missed the beaker, it altered the results. When the Cu was heated
to dry, a possible place for error was having the Cu pop out of the beaker. If the Cu was heated too
quickly and vigorously, the Cu would pop out and alter the results. The last main possible place for error
was leaving some Cu on the nail. If any Cu was left on the nail, it would alter the by causing less Fe
reacting and ultimately causing the results to be lower. This also caused the theoretical amount to be
higher. This could be fixed by being more thorough when removing the Cu from the nail.
Conclusion:
The purpose of the lab was to measure how many moles of iron would be consumed and copper
produced with the reaction of iron and aqueous copper (II) chloride. The procedure first involved
measuring the an empty beaker and nails before the reaction. The nails were put in a beaker with
copper (II) chloride. Copper was formed on the nails. The liquid in the beaker was poured out and the
copper on the nails scraped in the beaker. Again the nails and beaker were weighed. Theoretically,
1.608g of Cu should have formed in the reaction. 1.41g of Cu was formed which was lower than
expected and caused a 12% error. A major source of error was accidentally pouring copper out of the
beaker when getting rid of the copper (II) chloride. The results were inconclusive with a 12% error and
further experimentation is needed.