Chemistry - Mole Concept Question with Solution | TestHub

The chemical formula of urea is $N{H}_{2}CON{H}_2$.

Number of moles of urea $=\frac{5.4}{60}=0.09$ mol.

One molecule of urea contains $4$ hydrogen atoms.

Number of moles of hydrogen atoms $=4\times 0.09=0.36$ mol.

Total number of hydrogen atoms $=0.36\times N_A=0.36\times 6.022\times 10^{23}=2.16792\times 10^{23}\approx 2.168\times 10^{23}$.

Answer: $2.168\times 10^{23}$