An electric heater of power $600 \, W$ takes $8 \, \text{minutes}$ to evaporate $80 \, mL$ of water. The enthalpy of vaporization of water is ......... $kJ \, mol^{-1}$.

The heat of vaporisation and heat of fusion of $H_2O$ are $540 \, cal/g$ and $80 \, cal/g$. The ratio of $\frac{\Delta S_{vap}}{\Delta S_{fusion}}$ for water is :-

For a spontaneous process, the correct statement$(s)$ is (are):

Change in entropy for an ideal gas in a reversible isothermal process is given by:

$200 \ mL$ of $0.2 \ M \ HCl$ is mixed with $300 \ mL$ of $0.1 \ M \ NaOH$. The molar heat of neutralization of this reaction is $-57.1 \ kJ \ mol^{-1}$. The increase in temperature in $^{\circ}C$ of the system on mixing is $x \times 10^{-2}$. The value of $x$ is ....... . (Nearest integer)
[Given : Specific heat of water $= 4.18 \ J \ g^{-1} \ K^{-1}$
Density of water $= 1.00 \ g \ cm^{-3}$]
(Assume no volume change on mixing)

What is the difference between $\Delta H$ and $\Delta U$ for the combustion of methane at $25\,^oC$?