calculate the number of molecules in 0.75 moles of ch₄. x 10²³ molecules 8.0 4.5

Explanation:

Step1: Recall Avogadro's number

Avogadro's number $N_A = 6.022\times 10^{23}\text{ molecules/mol}$.

Step2: Calculate number of molecules

The number of molecules $N$ in a substance is given by $N=n\times N_A$, where $n = 0.75\text{ mol}$. So $N=0.75\text{ mol}\times6.022\times 10^{23}\text{ molecules/mol}$. $N = 4.5165\times 10^{23}\approx4.5\times 10^{23}\text{ molecules}$

Answer:

$4.5\times 10^{23}$ molecules