In a combustion reaction, one of the reactants is water oxygen carbon dioxide a metal

oxygen

Explanation:

Combustion is a type of chemical reaction in which fuel is reacted with oxygen to form carbon dioxide and water.

Example:

Reactants of a chemical reaction is defined as the substances which take part in a chemical reaction and undergoes a chemical change. Reactants are written on left side of the arrow.

Thus glucose and oxygen are reactants of combustion reaction.

Products are defined as the substance which are formed at the end of the chemical reaction.Products are written on the right side of the arrow.

Thus carbon dioxide and water are products of combustion reaction.

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o