PRoblem 1: For which of the following activities might you want to hire a chemist?

Abuilding a garage

Btesting a sample of water from a well

Cfinding a comet

Dexamining the structure of plant cells

PRoblem 2: Which of the following procedures involves a physical change in one of the substances?

Acreating salt by reacting sodium metal and chlorine gas

Ballowing a nail to rust

Cbuilding a model rocket propelled by mixing baking soda and vinegar

Dgrinding chalk into a fine powder

Verified Answer :

1) B, Not 100% sure though

2)Building a rocket is a physical change technically its not changing its composition its just changing its appearance, the fuel for it causes a chemical change, there is an answer that is more clear, Grinding chalk into a fine powder only changes its shape which is a physical change.