Evidence of a chemical change

All four of them

Color change

One evidence of a chemical change is color change. Sometimes if you mix two substances together they will form a new and diffrent color.

Gas being released

A different kind of chemical change occurs when you mix two or more substances

together, gas being released. Some chemicals when exposed to others release carbon dioxide making bubbles and or fizzing.

Temperature change

Some chemicals when exposed experience a chemical change known as a temperature change. Say for example when ice is exposed to warm weather it will change in temperature.

When a precipitate forms

Rarely when two liquds (and only liquids) are exposed to each other they form a solid mass.

An example would be silver nitrate (AgNO3) and sodium chloride (NaCl) when combined forms a precipitate.