Question

1 which of these is an example of a chemical reaction?
a atoms join together, causing a substance to gain mass
b atoms form a chemical bond, creating a new substance
c atoms break apart, causing a substance to lose mass

Explanation:

A chemical reaction involves the rearrangement of atoms to form new substances. In a chemical reaction, atoms form chemical bonds to create new substances. The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction, so options A and C which mention gain or loss of mass are incorrect as mass remains constant in a chemical reaction.

Answer:

B. Atoms form a chemical bond, creating a new substance