Which choices indicate a chemical change?

_ (Select all that apply.) _

two liquids mix and release an odor

two colors mix to make a new color

liquid turns to gas in the form of bubbles when boiling

two liquids form a precipitate

They all seem correct but only two should be.

Two liquids mix and release an odour.

Two liquids form a precipitate.

Step-by-step explanation:

If the two liquids mix and release an odour, that is a sign that a new substance has formed - a chemical change.

Similarly, if two liquids mix and form a precipitate, a new substance has formed - another chemical change.

B is wrong. The mixing of two colours is a physical change. The coloured substances don't change. Our eyes just combine the two colours into a new one.

C is wrong. When a liquid boils and forms bubbles of gas, the substance changes from the liquid to the liquid gaseous state, but it is still the same substance. Boiling is a hysical change.