If 115 g of a substance reacts with 84 g of another substance, what will be the mass
of the products after the reaction?

199 g

Explanation:

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

Explanation:

This law was given by french chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

For example:

In given reaction:

Reactant A = 115 g

Reactant B = 84 g

Product AB = ?

A      +      B    →    AB

115 g + 84 g  = 199 g

199 g =  199 g

i think that the answer is c