Why do you use salt to melt ice?

Answer 1

Salt works by lowering the melting or freezing point of water. The effect is termed 'freezing point depression'.

http://en.wikipedia.org/wiki/Freezing-point_depression

When you add salt to water, you introduce dissolved foreign particles into the water. The freezing point of water becomes lower as more particles are added until the point where the salt stops dissolving.

Answer 2

Salt lowers the freezing point of water, if you add salt to water, it will be harder to turn it into ice. For example, you need to make metal very hot to melt it, however you don't need as much to melt ice. you don't need as much heat to melt salted ice as you do to melt ice. So salted ice melts faster.
Salt will melt Ice

Salt will dissolve in water

Salt melts ice into water by contact, as it melts the ice, it dissolves, as it dissolves into the water it changes the chemical composition of the water decreasing the temperature at which it will freeze. Technically this is changing the thermal conductivity of water... The more salt in water, the colder the water needs to be before it can freeze. This concentration of Salt in water is referred to as salinity.

Answer 3

Rock salt forces the ice surrounding the can of ice cream mix to melt. The "brine solution" or liquid that forms in the wooden bucket absorbs heat from the mix and gradually lowers the temperature of the mix until it begins to freeze. If there were no salt added to the ice, it would melt at 32 degrees Fahrenheit and eventually the ice water and mix would come to equilibrium at 32 degrees. The ice cream mix, however, does not begin to freeze until its temperature falls below 27 degrees. Therefore, in order to freeze the mix, we need a salt concentration, or a ratio of 5 cups of ice to 1 cups of salt. At this concentration, our brine temperature should remain constant at 8 to 12 degrees F. This will give the rapid cooling and freezing. Adding salt to water (or ice) lowers the melting point of ice from 32F to about 15F. What this accomplishes is making really cold water. Water conducts heat better that ice since conduction has a lot to do with surface contact. Ice cubes don't actually make very good contact with the ice cream maker since there is a lot of air between the cubes. Water however, make a great conductor. So, if you can melt the ice and lower the temperature, you can freeze the ice cream while keeping the water from freezing.

Answer 4

Salt lowers the freezing point of water which is normally 0C. So if it's -5C outside, ice would freeze, but when we add salt, the freezing point lowers to something like -10C, so the ice will melt because it's not cold enough for it to freeze.

Answer 5

It lowers the freezing point of the water like any other salt. Rock Salt is mostly used on roads and sidewalks to melt ice because rock salt is cheap, but still efficient.

Answer 6

Can I use sea salt to melt ice and will wild life come out on the highways to lick the salt

Answer 7

Because it dosent waste your time and you could go out and hang out with your friends instead of waiting home and waiting and stareing at the ice to melt

Answer 8

Sea salt is available in different grades so you have to choose.