Chemistry
Clare McGrath
October 14, 2009
Pat McClelland
Cold Pack Laboratory
In this lab I was determining effective chemicals for use as cold packs. In this
experiment, the problem was finding out if the chemicals affect the temperature of the
water. While experimenting we discovered the independent variable was the type of
chemical we used in the foam cups, and the dependent variable was the temperature.
The control throughout the entire experiment was the amount of chemicals (50 mL of
water).
Purpose:
Materials:
o
10 grams of ammonium chloride (NH4C1)
o
10 grams of sodium chloride (NaCL)
o
10 grams calcium chloride (CaCL2)
o
Access to a watch or clock with a second hand
o
Access to an electronic balance
o
Access to distilled water
o
Scoopula 4 foam cups
o
1 graduated cylinder
o
1 stirrer
o
1 thermometer
o
Paper towels for cleanup
Procedure (part one):
o
Gather materials
o
Add 50 mL of water into foam cup
o
Measure 2g of each chemical
o
Add ammonium chloride to cup one
o
Take the temperature for cup one
o
Add calcium chloride to cup two
o
Take the temperature for cup two
o
Add sodium chloride to cup three
o
Take the temperature for cup three
o
Record the data, and find the coldest chemical.
Procedure (part two):
o
Gather materials
o
Fill foam cups with 50 mL of water
o
Place 1g of the coldest chemical into cup one
o
Take the temperature of cup one
o
Place 3g of the coldest chemical into cup two
o
Take the temperature of cup two
o
Place 4g of the coldest chemical into cup three
o
Take the temperature of cup three
o
Record the data, and find out what the best amount of the coldest chemical is.
Observations:
Part One
Time
0 minutes
1 minute
2 minutes
3 minutes
4 minutes
Average
Control
20 degrees Celsius
20 degrees Celsius
20 degrees Celsius
20 degrees Celsius
20 degrees Celsius
20 degrees Celsius
Ammonium chloride
20 degrees Celsius
19 degrees Celsius
19 degrees Celsius
18 degrees Celsius
18 degrees Celsius
18.8 degrees Celsius
Calcium Chloride
20 degrees Celsius
25 degrees Celsius
24.5 degrees Celsius
24 degrees Celsius
24 degrees Celsius
23.5 degrees Celsius
Sodium Chloride
20 degrees Celsius
20 degrees Celsius
20 degrees Celsius
20 degrees Celsius
20 degrees Celsius
20 degrees Celsius
3 grams
20 degrees Celsius
17 degrees Celsius
17 degrees Celsius
17 degrees Celsius
17 degrees Celsius
17.6 degrees Celsius
4 grams
20 degrees Celsius
17 degrees Celsius
17 degrees Celsius
17 degrees Celsius
17 degrees Celsius
17.7 degrees Celsius
Coldest Chemical
Part Two
Time
0 minutes
1 minute
2 minutes
3 minutes
4 minutes
Average
0 grams
20 degrees Celsius
20 degrees Celsius
20 degrees Celsius
20 degrees Celsius
20 degrees Celsius
20 degrees Celsius
1 gram
20 degrees Celsius
19.5 degrees Celsius
19 degrees Celsius
19 degrees Celsius
19 degrees Celsius
19.3 degrees Celsius
Best Amount
Conclusion
(Part one):
In this lab that my partner and I conducted, we were determining effective chemicals for
use as cold packs. Our problem was finding out if the chemicals affected the temperature of the
water. In part ones data, we found that the overall coldest chemical out of Ammonium Chloride,
Calcium Chloride, and Sodium Chloride was Ammonium chloride, which came out with the
average of 18.8 degrees Celsius, after being tested over a period of four minutes. My partner
and I believe that this conclusion is very accurate, and that we followed all of the steps correctly.
I have full confidence in my results and conclusions. The only thing that could have possibly
thrown off our data was that we occasionally moved the thermometer around causing the
chemical to be stirred up, but I don’t believe this would throw off our data by much.
(Part two):
In this lab that my partner and I conducted, we were determining effective chemicals for
use as cold packs. Our problem was finding out if the chemicals affected the temperature of the
water. In part twos data, we found that the overall Best amount out of 0 grams, 1 gram, 3
grams, or 4 grams was the three grams, which had the average of 17.6 degrees Celsius.
(Final):
As exhibited from the examples above, the coldest chemical was the Ammonium
Chloride (18.8 degrees Celsius), and the best amount would be three grams (17.6 degrees Celsius).
So in conclusion, if I were to redo this lab over again, I probably would have done it the same, with
the same lab partner because we followed all the steps clearly, and worked well together.