Question

The average kinetic energy in joules of molecules in 8.0 gm of methan at ${27}^{o}C$ is____________.

• A. $6.21\times {10}^{20}J/molecule$
• B. $6.21\times {10}^{21}J/molecule$
• C. $6.21\times {10}^{22}J/molecule$
• D. $3.1\times {10}^{22}J/molecule$

Answer 1

The correct option is B $6.21\times {10}^{21}J/molecule$

As we know,
$K.E.=\frac{3}{2}nRT$
$\frac{K.E}{Molecule}=\frac{3}{2}\times \frac{8}{16}\times \frac{300\times 8.314}{N_A}\times 21$
$=6.21\times {10}^{21}J/molecule$