What is a vapor? O A. A substance that has a much higher melting point and boiling
point than other similar substances
O B. A substance that is always in the solid or liquid phase at room
temperature
C. A substance that is in the gas phase at a temperature at which it
would normally be a solid or liquid
O D. A substance that forms a gas, but only at very high temperatures

in physics, a vapor or vapour is a substance in the gas phase at a temperature lower than its critical temperature, which means that the vapor can be condensed to a liquid by increasing the pressure on it without reducing the temperature. A vapor is different from an aerosol.

Explanation:

c

Explanation:

because vapor refers to a gas- phase material that normally exits as a liquid or as a solid under a given set of conditions

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.