Use the chemical reaction to answer the question.

Question

2H2 + 02 → 2H20
There are four atoms of hydrogen (H) before the reaction. How many atoms of hydrogen are present after the reaction?

Answer 1

In the chemical reaction 2H2 + O2 → 2H2O, there are four atoms of hydrogen (H) present before the reaction, as each molecule of H2 contains two hydrogen atoms, and there are two H2 molecules (2 x 2 = 4).

After the reaction, 2 molecules of water (H2O) are produced. Each molecule of H2O contains two hydrogen atoms. Therefore, in 2H2O, the number of hydrogen atoms is:

2 molecules of H2O x 2 H atoms per molecule = 4 H atoms.

So, there are still four atoms of hydrogen present after the reaction.