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Question 1

How do you know if something is going through chemical change?

Answer 1

Most chemical changes can’t be reversed; as well as it creates something new.

e.g: Bread becoming toast, you can’t make toast go back to bread!

Question 2

How do you know if something is going through a physical change?

Answer 2

Most physical changes can be reversed, but just look different

e.g: A melted ice cube looks different, but the molecules are the same and the water state can be reversed after being in the freezer for awhile!

Question 3

when salt disolves in water it is a..

Answer 3

physical change, because you can filter out salt and the dissolution of salt in water is easily identified as a physical change, because if the water is allowed to evaporate, the salt remains after all the water has evaporated, meaning it has not been permanently altered. Adding salt to water changes the osmotic potential and vapour pressure of the solution3.