Chapter 6, Problem 19A

Summary Introduction

Introduction:

Chemical reactions happen when chemical bonds between atoms are formed or broken. The compounds that go into a chemical reaction are called the reactants, and the compounds produced at the end of the reaction are called as the products.

Answer to Problem 19A

Correct answer :

The correct answer is option A. chemical reactions.

Explanation of Solution

Explanation/justification for the correct answer :

Option A. chemical reactions. When a chemical reaction occurs, molecular bonds are broken and other bonds are formed to make different molecules. For example, the bonds of two water molecules are broken to form hydrogen and oxygen. So, the correct answer is option A.

Explanation for incorrect answer :

Option B. elements. An element is a substance made up of atoms having the same atomic number that means all atoms have the same number of protons. So, this is an incorrect answer.

Option C. isotopes. Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons, they are formed that way. So, this is an incorrect answer.

Option D. polar molecules. Polar molecules occur when there is an electronegativity difference between the bonded atoms. So, this is an incorrect answer.