how many carbon atoms are there on the reactant side of this equation? ch4 + 2o2 -> co2 + 2h2o

0

2

1

4

4 carbon atoms on the reactant side.

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

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.

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 there are 4 carbon atoms on the reactant side.

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.