Question

how many molecules are in 2.5 mol of nacl? 1.5 molecules 1.5 x 10^24 molecules 1.5 x 10^23 molecules 4.15 molecules

Explanation:

Step1: Recall Avogadro's number

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

Step2: Calculate the number of molecules

The number of molecules $N$ in a substance is given by $N = n\times N_A$, where $n$ is the number of moles. Here, $n = 2.5\text{ mol}$. So $N=2.5\text{ mol}\times6.022\times 10^{23}\text{ molecules/mol}= 1.5055\times 10^{24}\text{ molecules}\approx1.5\times 10^{24}\text{ molecules}$.

Answer:

B. $1.5\times 10^{24}$ molecules