Question

Which sample at STP has the same number of molecules as 5 liters ${NO}_2\left(g\right)$ at STP?

• A. 5 gram of $H_2\left(g\right)$
• B. 5 liters of ${CH}_4\left(g\right)$
• C. 5 moles of $O_2\left(g\right)$
• D. $5\times {10}^{23}$ molecules of ${CO}_2\left(g\right)$

Answer 1

Answer: (B)

5 liters of ${CH}_4\left(g\right)$

$5lN{O}_2$ at STP

No. of molecules$=\frac{5}{22.4}mol=\frac{5}{22.4}\times N_A$ molecules

A) $5ℊ$ of $H_2\left(g\right)$

No. of moles$=\frac{5}{2}mol=\frac{5}{2}\times N_A$ molecules

B) $5l$ of $C{H}_4\left(g\right)$

No. of moles of $C{H}_4=\frac{5}{22.4}mol=\frac{5}{22.4}{N}_A$ molecules

C) $5mol$ of $O_2=5N_A{O}_2$ molecules

D) $5\times {10}^{23}$ molecules of $C{O}_2\left(g\right)$

Molecules of $5lN{O}_2\left(g\right)$ at STP$=5l$ of $C{H}_4\left(g\right)$ molecules at STP

Therefore, option $B$ is correct.