For the complete combustion of methanol
$CH_3OH_{(l)} + \frac{3}{2} O_{2(g)} \rightarrow CO_{2(g)} + 2H_2O_{(l)}$
the amount of heat produced as measured by a bomb calorimeter is $726 \ kJ \ mol^{-1}$ at $27^{\circ}C$. The enthalpy of combustion for the reaction is $-x \ kJ \ mol^{-1}$,where $x$ is $.....$ (Nearest integer).
(Given: $R = 8.3 \ J \ K^{-1} \ mol^{-1}$)

Which of the following is/are true about the reversible isothermal expansion of an ideal gas?
$(a) \ \Delta U = 0$
$(b) \ q = 0$
$(c) \ \Delta T = 0$
$(d) \ q = 2.303 \ nRT \ \log_{10} \left( \frac{V_2}{V_1} \right)$

Which of the following relations between enthalpy change $(\Delta H)$ and internal energy change $(\Delta U)$ is correct for the given reactions?

Calculate $\Delta S_{total}$ for the following reaction at $300 \ K$.
$NH_4NO_{3(s)} \longrightarrow NH_4^+{(aq)} + NO_3^-{(aq)}$ $(\Delta H = 28.1 \ kJ \ mol^{-1}, \Delta S_{sys} = 108.7 \ J \ K^{-1} \ mol^{-1})$

Given below are two statements:
Statement-$I$: For isothermal irreversible change of an ideal gas,$q = -w = P_{\text{ext}} (V_{\text{final}} - V_{\text{initial}})$
Statement-$II$: For adiabatic change,$\Delta U = W_{\text{adiabatic}}$
The correct answer is

Fill in the blanks given below:
$(i)$ The law of thermodynamics is actually the law of ......... .
$(ii)$ $A$ thermometer measures temperature according to the ......... law of thermodynamics.
$(iii)$ The foundation of thermochemistry is based on the ......... law of thermodynamics.
$(iv)$ The amount of heat required to raise the temperature of a substance by $1^{\circ}C$ is called the ......... of that substance.