Respuesta :
Answer: Chemical change; Chemical property of heat of combustion
Explanation:
A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions.
Example: Melting of ice
Physical property is defined as the property of a substance which becomes evident during physical changes. Example: Melting point
A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions.
Example: combustion
[tex]C+O_2\rightarrow CO_2[/tex]
Chemical property is defined as the property of a substance which becomes evident during chemical changes. Example: Reactivity with other substances
Thus when a piece of coal and a piece of wood is burnt , there is formation of new substances and thus is a chemical change. Combustion is a chemical property as it is reactivity of a substance with oxygen.