Why does adding salt to icewater make it colder?

Question

I understand about lowering the freezing point of H2O. But if cold is the absence of heat then adding salt doesn't remove any energy/heat. Why doesn't it simply melt into liquid and stay the same temperature?

Answer 1

Does adding salt to ice and water cause a temperature drop? Yes. This is how old-fashioned ice cream makers lowered the temperature of the ice cream below water's ordinary freezing point. A mixture of rock salt, ice, and water packed in the bucket around the ice cream mix can bring the temperature down as low as -21°C.

Why does the temperature drop? Energy is required to snap the hydrogen bonds that hold the ice together. The melting ice draws that energy from the surrounding solution as heat.

Answer 2

It lowers the melting point as you said. However, it also changes the latent heat of fusion. You know, the large amount of energy used to hold the ice together? Where when melting, the ice temperature do not change for some time ~

Answer 3

Salt melts some of the ice, drawing heat from the rest, making it colder.

Answer 4

It doesn't make it colder. Salt freezes at a lower temperature than water, so when mixed in water, in means that it has to be colder before the salt/water mixture will freeze.

Answer 5

Salt does not make water less warm. It lowers the freezing factor. So say organic water freezes at 32 levels F. including some salt won't make the water less warm, what it does is decrease the freezing factor slightly, in step with probability to 31 or 30 levels.

Answer 6

Just wondering that when I made homemade ice cream today. Why am I adding salt to the ice cubes???? Especially when you put salt on ice outside in the winter to help it melt!!!

Answer 7

Yes, right on..

Want to see something cool???

Take a glass of salt water, and put in some cubes of dry ice (solid CO2).. Freeze away!!!

It's perfect when you have warm beer less than 10 mins before a party!!

Answer 8

Because salt needs energy to become diluted by the water