Which of the following is a sign of a chemical change? * Change in shape
Melting from solid to liquid
Formation of a precipitate
Change in size

Iwould appreciate if someone could me.

What is a main difference between a mixture and a pure substance? a mixture is only a liquid, but a pure substance can be in any state.a mixture looks the same throughout, but a pure substance does not.1 a mixture can vary in composition, but a pure substance has a set composlo a mixture can be made up of a single compound, but a pure substance car

Which of the four hypothetical substances you investigated would be most harmful to living organisms? 50 points!