Question

a student adds 15 g of baking soda to 10 g of acetic acid in a beaker. a chemical reaction occurs and a gas is given off. after the reaction, the mass of the remaining in beaker is 23 g. has mass been converserved in the reaction? explain.

Answer 1

The chemical equation representing the reaction between baking soda and acetic acid :

$NaHCO_{3}(aq)+CH_{3}COOH(aq)-->CH_{3}COONa(aq)+H_{2}O(l)+CO_{2}(g)$

According to the Law of conservation of mass, the overall mass is conserved in a chemical reaction. That is total mass of reactants is equal to the mass of the products.

Given here Mass of Baking soda = 15 g

Mass of acetic acid = 10 g

Total mass of the reactants = 15 g +10 g = 25 g

After the reaction, total mass of products = 23 g

This difference in masses must be because one of product carbon dioxide is a gas, which is lost and hence the mass of products is lower than the mass of reactants. Therefore, the mass is conserved in this reaction.