Which of the following are phase changes? select all that apply.
a) liquid freezing
b) solid melting
c) ice melting
d) sublimation of a solid
e) paper burning

Options A, B, C, and D are all representing phase changes.

Explanation:

Phase change means change in the state of a substance from one form to another that is change of a liquid into solid, liquid into gas and vice versa.

In liquid freezing, the liquid is changing into solid so here phase is changing.

In solid melting, solid is changing into liquid so here phase is changing.

In ice melting, solid is changing into liquid so here phase is changing.

In sublimation of a solid, the solid changes to gas without changing into liquid. So, here also phase is changing.

When paper is burning, it is a chemical change as a new substance is formed which cannot be reversed into paper again.

Therefore, options A, B, C, and D are all representing phase changes.

yes the answer is total mass in unchanged   : )