Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

[Q]: You call the separation of ions that occurs when a solid ionic compound dissolves dissociation.
[A]: What do you call the separation of ions that occurs when a solid ionic compound dissolves?

[Q]: Some materials have negative heats of solution; the dissolution of one of these solutes in water is called?
[A]: Some materials have negative heats of solution; the dissolution of one of these solutes in water is called?

[Q]: Matter cannot be created or destroyed in a chemical reaction.
[A]:
What cannot be created or destroyed in a chemical reaction?