Question

A solution of ammonia and water contains 4.20×1025 water molecules and 6.20×1024 ammonia molecules. how many total hydrogen atoms are in this solution? enter your answer numerically.

Answer 1

The molecular formula of water and ammonia is
`H_2O` and
`NH_3` respectively.

From the atomic symbol of water it is clear that 1 mole of water contains 2 moles of hydrogen.

So,
`4.20* 10^(25)` molecules of water contains
`2* 4.20* 10^(25) = 8.40* 10^(25)` atoms of hydrogen.

From the atomic symbol of ammonia it is clear that 1 mole of ammonia contains 3 moles of hydrogen.

So,
`6.20* 10^(24)` molecules of ammonia contains
`3* 6.20* 10^(24) = 18.6* 10^(24)` atoms of hydrogen.

Total number of hydrogen atoms present in the solution = number of hydrogen atoms in water + number of hydrogen atoms in ammonia.

Substituting the values,

Total number of hydrogen atoms present in the solution =
`8.40* 10^(25)+1.86* 10^(25)`

Total number of hydrogen atoms present in the solution =
`10.26* 10^(25) atoms`.

Hence, the total number of hydrogen atoms present in the solution is
`10.26* 10^(25)` atoms.