Question

How many molecules are in 42.3g sample of water, H2O?

Answer 1

Answer: There are 14.152 molecules in 42.3 g sample of water,
`H_(2)O`.

Step-by-step explanation:

According to the mole concept, 1 mole of every substance contains
`6.022 * 10^(23)` atoms.

As mass of water (molar mass = 18 g/mol) is given as 42.3 g. Therefore, moles of water are as follows.

`No. of moles = (mass)/(molar mass)\\= (42.3 g)/(18 g/mol)\\= 2.35 mol`

Hence, molecules of water are calculated as follows.

`2.35 * 6.022 * 10^(23) molecules\\= 14.152 molecules`

Thus, we can conclude that there are 14.152 molecules in 42.3 g sample of water,
`H_(2)O`.