Are these a compound, element, mixture of compounds, mixture of elements, and compounds or mixture of elements.

Which is a chemical property of iron? a. it forms iron oxide (rust) when exposed to moisture and air. b. it is a gray–black metal that is hard to the touch. c. it has a melting point of 2795°f (1536°c). d. it is a good conductor of heat

The formation of a solid, also known as a is an indication of a chemical change. precipitate particulate particle powder

How does a nuclear reactor produce electricity?