“Phase Change of Water vs Salt Water” Answers
Data & Analysis:
Note that this experiment does not always give the same results. There are other
factors which are not controlled in this simple experiment that can change the
outcome.
1) Substance that boiled first Water (hopefully)
Initial Water Final Water Number of mL Line Level Line Level Vaporized Water Salt Water Ideally, more mL of water than salt water vaporized.
2) Before you started to heat the two liquids, why was the location of the salt water line not the
same as the regular water line even though the same amount of mass was contained in each
beaker?
Some of the salt fills in the empty spaces in the water, so the same mass of salt water has
less volume than water.
3) Based on your observations, which substance has the higher specific heat capacity, fresh
water or salt water? Describe the proof you have for this.
Salt Water (hopefully)
The substance that began to boil last is the one that has the higher specific heat capacity
because it required more energy to change temperature and reach the boiling point.
4) Based on your experiment, which has a higher latent heat of fusion vaporization, regular
water or salt water? Describe the proof you have for this.
Salt Water (hopefully)
The substance that changed phase the least is the one that has the higher latent heat of
vaporization. This substance requires more energy than the other to change phase.
Ciardi, T Water vs Salt Water 1 General Question:
1) Regarding adding salt to water to make pasta cook faster, when do you think you should add
the salt?
a. Add the salt before the water boils
b. Add the salt after the water boils
c. Do not add salt
Defend your answer.
Ideally, your water began to boil first. Boiling allows heat to be transferred throughout
the fluid. It is best to allow the water to begin boiling before adding the salt so that it
begins transferring heat as quickly as possible to your pasta. Once the water is boiling,
adding salt will bring the boiling water to a higher temperature which will cook your
pasta faster.
Ciardi, T Water vs Salt Water 2