Question

61.4 g n₂
express your answer using three significant figures.
n =
molecules

Explanation:

Step1: Calculate moles of \(N_2\)

Molar mass of \(N_2\) is \(2\times14.01 = 28.02\space g/mol\). Moles \(n=\frac{mass}{molar\space mass}=\frac{61.4\space g}{28.02\space g/mol}\approx2.191\space mol\).

Step2: Calculate number of molecules

Using Avogadro's number \(N_A = 6.022\times10^{23}\space molecules/mol\), number of molecules \(N = n\times N_A=2.191\space mol\times6.022\times10^{23}\space molecules/mol\approx1.32\times10^{24}\space molecules\).

Answer:

\(1.32\times10^{24}\)