When a sample of blue crystals is heated, a vapour is given off and a white powder remains. Analyze whether a physical or a chemical change occurred. Give reasons for your answer.

It needs to choose one of the following from each box. If its either physical chemical or incomplete meaning that it doesnt match the one from the original (the one on top).

a black solid is heated in a tube that is completely evacuated of air. hydrogen is added to the tube. an oranges powder is formed and water vapor (H2O) is seen on the outside of the tube. is this an example of a physical or chemical change? expalin

Magnesium metal is very malleable and is able to be pounded and stretched into long, thin, narrow "ribbons" that are often used in the introductory chemistry lab as a source of the metal. If a strip of magnesium ribbon is ignited in a Bunsen burner flame, the magnesium burns brightly and produces a quantity of white powder. Is the process a physical or chemical change?