How salt saturation affect boiling point? Experiment?

Question

I have a science assignment which is an experiment. The aim is to assess how salt affects boiling point of water. I am using 100 ml of water. Is it better to use % saturation eg like add 25ml saturated solution and 75ml water, 50ml saturated 50ml water etc. Or just use 100ml of water and add 5g of salt each time. Is percentage saturation accurate as each time you increase % saturation in 100ml of water, you are changing the amount of water (but perseve mass of 100g).

Answer 1

I assume you are investigating boiling point elevation.

If that is indeed the case, the simplest method would be to keep the volume of water constant and salt composition as the variable. Eg: Keep 100ml of water for use with 5g, 10g, 15g, 20g, etc salt.

Mixing saturated solutions into portions of water is actually exactly like adding salt into 100ml water. For the former, you mixed salt into water first, then diluted it again. For the latter, you just added the same amount of salt once into your fixed total amount of water.

Therefore, percentage saturation is accurate because you merely just broke an equation into more expressions, for eg:

x + 100

broken into

(x + 50) + 50

is still equivalent to the first equation.