$A$ calorimeter contains $0.2 \ kg$ of water at $30^{\circ} C$. $0.1 \ kg$ of water at $60^{\circ} C$ is added to it,the mixture is well stirred and the resulting temperature is found to be $35^{\circ} C$. The water equivalent of the calorimeter is $:-$ (in $J / K$)

$A$ gas (Molar mass $= 280 \ g \ mol^{-1}$) was burnt in excess $O_2$ in a constant volume calorimeter and during combustion the temperature of calorimeter increased from $298.0 \ K$ to $298.45 \ K$. If the heat capacity of calorimeter is $2.5 \ kJ \ K^{-1}$ and enthalpy of combustion of gas is $9 \ kJ \ mol^{-1}$,then the amount of gas burnt is $...... \ g$. (Nearest Integer)

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: $R = 8.314 \ J \ K^{-1} \ mol^{-1}$)

The work done during the combustion of $9 \times 10^{-2} \ kg$ of ethane,$C_2H_{6(g)}$ at $300 \ K$ is (Given $R = 8.314 \ J \ K^{-1} \ mol^{-1}$,atomic mass $C = 12$,$H = 1$). (in $kJ$)

$9.0 \ g$ of $H_2O$ is vaporised at $100 \ ^oC$ and $1 \ atm$ pressure. If the latent heat of vaporisation of water is $x \ J/g$,then $\Delta S$ is given by

For an endothermic reaction where $\Delta H$ represents the enthalpy of the reaction in $kJ/mole$,the minimum value for the energy of activation $(E_a)$ will be: