science fair experiment on ice and salt

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christophershiney
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Joined: Tue Nov 29, 2016 4:17 pm
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science fair experiment on ice and salt

Post by christophershiney »

|I just have a few questions I need for my experiment from a pro.

1) What chemical is in salt that makes ice melt?

2) Why does the chemical reaction occur?

3)How does temperature effect the time it takes to melt the ice?

4)What are the key components of salt?

5)Why doesn't ice evaporate instead of melting when it comes to salt?
stephen_lee
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Joined: Wed Oct 12, 2016 1:40 pm
Occupation: Student

Re: science fair experiment on ice and salt

Post by stephen_lee »

Hi Christopher,

Some good questions about solutions chemistry.

1) The salt itself is making the ice melt. The salt dissolves in the ice and lowers the freezing point of the water in the ice. Since the freezing point is lower now, the water that was once frozen will melt if the temperature of the ice is now above the new freezing point.

2) So this is a technicality, but there isn't an actual reaction that occurs, the salt just dissolves in the water and no new chemicals are formed which would only happen in a chemical reaction. The salt can dissolve in the water, because water molecules have a slightly positive side and a slightly negative side. This allows the water molecules to pull apart the salt and dissolve it.

3) Temperature will affect the rate at which the ice will melt, with the greater the temperature difference between the ice and its surroundings causing a faster rate of melting. To explain this picture an ice cube in a glass of room temperature water. Then picture what would happen with an ice cube in a boiling pot of water. The ice cube in the boiling water would melt much quicker.

4) Salts are made out of ions, which are just charged particles, a positive cation and a negative anion. The two ions attract each other since they have opposite charges and form an ionic bond to make a salt.

5) Ice can evaporate depending on the environmental conditions. This is explained by what is called a phase diagram which you can look up to learn more about.

Good luck with your experiment!
Stephen
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