The molar heat capacity for an ideal gas at constant pressure is $20.785 \ J \ K^{-1} \ mol^{-1}$. The change in internal energy is $5000 \ J$ upon heating it from $300 \ K$ to $500 \ K$. The number of moles of the gas is [Nearest integer] (Given: $R = 8.314 \ J \ K^{-1} \ mol^{-1}$)

$A$ system consisting of $1 \, mole$ of an ideal gas undergoes a reversible process,$A$ $\rightarrow B$ $\rightarrow C$ $\rightarrow A$ (schematically indicated in the figure below). If the temperature at the starting point $A$ is $300 \, K$ and the work done in the process $B \rightarrow C$ is $1 \, L \, atm$,the heat exchanged in the entire process in $L \, atm$ is $....$

Heat of combustion of $CH_4, C_2H_4$ and $C_2H_6$ are $-890, -1411$ and $-1560 \ kJ/mol$ respectively. Which has the lowest calorific value?

The heats of combustion of $C_2H_4, C_2H_6$ and $H_2$ are $-1409.5 \, kJ, -1558.3 \, kJ$ and $-285.6 \, kJ$ respectively. The heat of hydrogenation of ethene is ...... $kJ$.

For the process $H_2O_{(l)} \rightarrow H_2O_{(g)}$ at $100^{\circ}C$ and $1 \ atm$ pressure,which of the following is true?

If water vapour is assumed to be a perfect gas,the molar enthalpy change for the vaporisation of $1 \ mol$ of water at $1 \ bar$ and $100^{\circ} C$ is $41 \ kJ \ mol^{-1}$. Calculate the internal energy change when $1 \ mol$ of water is vaporised at $1 \ bar$ pressure and $100^{\circ} C$.