Question

If R = universal gas constant, the amount of heat needed to raise the temperature of 2 mole of an ideal monoatomic gas from 273 K to 373 K when no work is done

• A. 100 R
• B. 150 R
• C. 300 R
• D. 500 R

Answer 1

Answer: (C)

300 R

For an Ideal Gas, the internal energy is only a function of the gas temperature and is a measure of the mean translational kinetic energy of the gas atoms.
From the first law of thermodyanics

$\Delta Q=\Delta U+\Delta W=0\Rightarrow \Delta Q=\Delta U=\frac{n}{2}R\Delta T$

where n= degree of freedom for monoatomic gas i.e=3
$=\frac{3}{2}\times 2R(373-273)=300R.$