what is the difference between a compound and a mixture?

Question

im having a test tomorrow and i have no idea

Answer 1

A compound is a chemical combination of two or more elements. A mixture is physical combination of two substances. A mixture can be separated by physical means. A compound can only be separated into its elements by chemical means.

Water is a compound. It can only be separated into hydrogen and oxygen by an electric current. Sand and salt are a mixture. Add water, water dissolves the salt, filter the salt wateraway from the sand, evaporate the salt water, and you've separated sand and salt.