Question

How many molecules are there in 45.0 grams of CH4?

Answer 1

Answer:$16.93\times 10^{23}\ \text{molecules}$

Explanation:

Given

Mass of $CH_4$ $m=45\ gm$

Molar mass of $CH_4$ is $12+4\times1=16$

No of moles of $CH_4$ $=\dfrac{\text{Mass}}{\text{Molar mass}}=\frac{45}{16}$

No of Molecules in 45gm of $CH_4$ is

$\Rightarrow N_A\times\frac{45}{16}=6.022\times 10^{23}\times \frac{45}{16}\\\Rightarrow 16.93\times10^{23}\ \text{molecules}$