The Concept:
Solution Boiling Point of Salt and Water
Water has a boiling point of 100.0C most places on the planet when it is in its pure form. However when another solid or liquid is added to the water, the pure water now becomes a mixed solution who’s physical properties such as boiling point change. In this exercise students will investigate this physical change using a mixture of regular table salt and water. Several trials will be tested using identical amounts of water and different amounts of salt. Students will record the boiling points of each solution and analyze the results.
Students will also be required to calculate both the
solution concentration of salt in the water, and the mass percent of the salt
solution. The solution concentration
can be calculated by dividing the mass of the salt (in grams) in the solution
by the total amount of water (In milliliters) used.
So for example if a student dissolved 100.0grams of salt into
1000.0ml of water, the solution concentration in terms of salt would be…
| 100.0g of salt |
= |
0.100g of salt/ml of water |
| 1000.0ml of water |
To calculate mass percent of the salt solution, divide the
mass of salt in the solution by the total mass of the solution, and multiply by
100. The calculation is shown below,
again using the example of 100.0g of salt in 1000.0ml of water. We will be using the conversion of 1.0g of
water = 1.0ml of water for this calculation….
| Mass % |
= |
100 |
x |
 |
mass of
salt |
 |
| the total mass of the solution |
| Mass % |
= |
100 |
x |
|
100.0 g |
|
| (100.0 g of salt + 1000.0 g of water) |
| Mass % |
= |
100 |
x |
|
100.0 g |
|
| 1100.0 g |
