What is the number of hydrogen atoms present in 5.4 g of urea?

Number of hydrogen atoms in 5.4 g of urea

Urea has the formula CO(NH$_{2}$)$_{2}$, with a molar mass of approximately 60 g/mol (simplified from 60.062 g/mol for calculation). In one molecule, there are 4 hydrogen atoms.

The number of moles in 5.4 g is $n = \frac{5.4}{60} = 0.09$ mol.

Using Avogadro's number, $N_{A} = 6.022 \times 10^{23}$, the number of hydrogen atoms is $0.09 \times 6.022 \times 10^{23} \times 4 = 2.168 \times 10^{23}$.

This corresponds to option C.