Combustion, or __________, is an example of one of the most familiar chemical changes. Melting of ice, likewise, is one of the most common examples of physical changes. When a piece of coal burns, combines with the carbon in the coal. The products are carbon dioxide gas, water vapor, and a lot of ash. After careful measurements are taken, the of the reactants (coal and oxygen) is to the mass of the products (carbon dioxide, water vapor, and ash). During the_________ reaction, the quantity of matter is unchanged. Similarly, when 10 grams of ice__________ , grams of water is obtained. Mass is_________ in this change as well.