Question

A solution of ammonia and water contains 2.10×1025 water molecules and 7.10×1024 ammonia molecules. How many total hydrogen atoms are in this solution?

Answer 1

There are 6.33 × 10²⁵ hydrogen atoms in this solution in total.

Explanation

• There are two hydrogen atoms in each water $\text{H}_2\text{O}$ molecule.
• There are three hydrogen atoms in each ammonia $\text{NH}_3$ molecule.

2.10 × 10²⁵ water molecules and 7.10 × 10²⁴ ammonia molecules will contain

$2 \times 2.10 \times 10^{25} + 3 \times 7.10 \times 10^{24} = 6.33 \times 10^{25}$ hydrogen atoms in total.