Question

Consider following unit values of energy
I. $1\, L$ atm,
II. $1$ erg,
III. $1 \,J$
IV. kcal,
Increasing order of these values is

• A. I = II = Ill = IV
• B. I < II < III < IV
• C. II < III < I < IV
• D. IV < l < III < II

Answer 1

Answer: (C)

$R=0.0821 \,L \,atm\, mol ^{-1} \,K ^{-1}$
$=8.314 \times 10^{7}$ ergs $mol ^{-1} \,K ^{-1}$
$=8.314\, J \,mol ^{-1} K ^{-1}$
$=0.002 \,kcal\, mol ^{-1}\, K ^{-1}$
$\therefore \,1\, L$ atm $=\frac{R}{0.0821}$ mol $k $
$1$ erg$=\frac{R}{8.314 \times 10^{7}}$ mol $k$
$1 \,J =\frac{R}{8.314} $ mol $K$
$1$ kcal $=\frac{R}{0.002}$ mol $K$
Thus, $ I < II < I < IV$