Is argon an example of an element, compound, heterogeneous mixture, or a homogeneous mixture

List four observations that indicate that a chemical reaction may be taking place

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

Particle model to predict what will happen if a sharp object creates a hole in the soccer ball