Question

The average kinetic energy of one molecule of an ideal gas at $27^{\circ}$C and $1 \,atm $ pressure is

• A. $900 \,cal \,K ^{-1} \,mol ^{-1}$
• B. $6.21 \times 10^{-21} \,JK ^{-1}$ molecule $^{-1}$
• C. $336.7 \,JK ^{-1}$ molecule $^{-1}$
• D. $3741.3 \,JK ^{-1}\, mol ^{-1}$

Answer 1

Answer: (B)

Average kinetic energy per molecule
$=\frac{3}{2} k T$
or $=\frac{3}{2} \frac{R}{N_{0}} T$
$=\frac{3}{2} \times \frac{8.314}{6.023 \times 10^{23}} \times 300$
$=6.21 \times 10^{-21} \,JK ^{-1}$ molecule $^{-1}$