Question

18.0 mL of water contains 6.022 x 1023 water molecules. How many hydrogen atoms are in 1.00 L of water? (Each water molecule, H2O, contains two hydrogen atoms.)

Answer 1

Solution :

lt is given that in 18 mL of water their are $6.022\times 10^{23}$ water molecules.

We know, that 1 molecule of water contains 2 atoms of hydrogen.

Hydrogen atom in 18 mL water is,

$2\times 6.022\times 10^{23} = 12.044 \times 10^{23}$ .

So, number of hydrogen atoms in 1 L = 1000 mL are :

$N = \dfrac{1000}{18}\times 12.044\times 10^{23}\\\\N = 6.69 \times 10^{25}\ atoms$

Hence, this is the required solution.