Abel Scheider and Bauke Kok
Summary
The effect salt has on the melting process of ice is well known, salt lowers the freazing point of ice and therefore forces it to melt. The most common used salt for this purpose is
NaCl. But other salts can be used as well. In our inquiry we had a look at the effect different kinds of salts have on the melting proces on ice. We approached this matter with the question: what influence does the
Introduction
In the winter, when the mercury of the thermometer drops below zero, ice on the roads is a very common problem.
This ice can create very dangerous situations, because the ice makes it difficult for traffic to stop quickly. To melt the ice the government uses salt.
This is effective because salts brake down the hydrogen bonds in H
2
O(s) and thereby lower the freezing point of the ice by 1.86 degree Celsius. The common salt that people use to clear the roads is NaCl which is very cheap and not very harmful to the environment. In our experiment we want to investigate if the mass of the ions in the resolution has consequences for the melting process of ice. For our experiment we used 3 different salts: BaCl
2
, MgCl
2
and CaCl
2
.
We only used salts with two Cl ions to make sure that our results weren’t asffected by this.
Our hypothesis is that the molar mass doesn’t affect the melting process and that the results of the melting-trajects mass of the ions in a salt have on the melting process? We thought it wouldn’t have any effect. But our results showed that it does make a little difference. Because of this you could say that a heavier salt should be used to clear the roads. But since there are also other requirements to a melting salt like price and influence on the environment, you can’t be sure about this. will be comparable with each other.
Salt brakes the hydrogen bonds in ice, and that makes the ice melt. The mass of the salt ions therefore shouldn’t matter, only the number of ions and the charge. Below you can see the chemical
have used. equation of the salts that we
+2Cl BaCl
2
→ Ba 2+
MgCl
2
→ Mg 2+
BaCl
2
→ Ba
Approach
2+
+2Cl
+2Cl
-
-
For our experiment we took six measure cylinders. In these cylinders we put coffee filters. Then we took
0.025 mole of MgCl
2
, which weights
2.4 gram 0.025 mole of BaCl
2
, which weights 5.2 gram and 0.025 mole of
CaCl
2
, which weights 2.8 gram. After weighing these salts we filled all three coffee filters with 100 gram of crushed ice. Then we added a different kind of salt to each filter. After that we

watched the melting process. We repeated this process twice
Data gathering
Every half a minute we watched and noted the amount of melting wather that came dripping down from the coffe filter into the cylinder. After averaging both the results we came to the following.
Results
Time(in minutes)
0
0:30
1:00
1:30
MgCl2 BaCl2 CaCl2
0
5.7
8.4
9.3
0
5.3
8.2
9.9
2:00 10.2 11
2:30 10.8 11.8
0
4.5
6.2
7
7.9
8.8
3:00
3:30
11.3 12.5 9.9
12 13.6 10.6
4:00 12.7 14.3 11.1
4:30 13.5 15.2 11.7
5:00 14.2 16 12.4
5:30 14.6 16.7 13.1
6:00 15.1 17.4 13.5
6:30 15.6 18 14
7:00 16 18.5 14.4
7:30 16.4 19.1 14.9
8:00 17 19.8 15.5
8:30 17.4 20.4 16.1
9:00 17.6 20.9 16.5
9:30 17.9 21.5 17
10:00 18.3 22 17.5
25
20
15
10
5
0
Time in minutes
Discussion and conclusion
In every experiment it is impossible to do everything perfect. We have tried hard to keep the variables constant but it is very hard if you have to work with melting ice. It is almost impossible to keep the conditions exactly the same every time you do your experiment.
The condition of the ice depends on the way it is crushes and the volume of the ice. The fact that the conditions of the weren’t exactly the same is visible in the results. You can see that there big is difference in the volume of the melted ice after one minute. The differences are to big for just one minute if you look to the rest of the results. Another thing that could have affect the results is the figure of the salts. MgCl2 for example was very fine and consist of small parts, on the contrary Cacl2 wasn’t very fine and consist of bigger parts. This could have affected the results. It is possible that it was more difficult for the bigger parts CaCl2 to brake down the hydrogen bonds as for the smaller parts of MgCl 2. As you can see in the graphic the speed of the melting ice became lower and lower. You can
MgCl2
BaCl2
CaCl2

explain this by the fact that we started our experiment with a little melt water: this melt water goes straight through the coffee filter and may have caused an abnormality in the results. We had this problem espacially in our second experiment. However, the conclusion we can draw from our inquiry is that the mass of the ions in a salt does matter for the speed of the melting proces of the ice. This is because
BaCl2, being the heaviest molecule of the three, clearly caused the most melting water.