Question

Calculate the number of molecules in a 45.6 gram sample of C2H4.

Answer 1

Answer: The number of molecules in a 45.6 gram sample of $C_{2}H_{4}$ are $9.78 \times 10^{23}$.

Explanation:

Given: Mass of $C_{2}H_{4}$ = 45.6 g

Molar mass of $C_{2}H_{4}$ is 28.05 g/mol.

Therefore, number of moles of $C_{2}H_{4}$ are calculated as follows.

$No. of moles = \frac{mass}{molarmass}\\= \frac{45.6 g}{28.05 g/mol}\\= 1.62 mol$

According to the mole concept, 1 mole of every substance contains $6.022 \times 10^{23}$ molecules. Hence, number of molecules present in 1.62 mol are calculated as follows.

$1.62 \times 6.022 \times 10^{23}\\= 9.78 \times 10^{23}$

Thus, we can conclude that the number of molecules in a 45.6 gram sample of $C_{2}H_{4}$ are $9.78 \times 10^{23}$.