Given the following thermochemical equations:
$(i) S_{(s)} + \frac{3}{2} O_{2(g)} \rightarrow SO_{3(g)} + 2x \, kcal$
$(ii) SO_{2(g)} + \frac{1}{2} O_{2(g)} \rightarrow SO_{3(g)} + y \, kcal$
Find the heat of formation of $SO_{2(g)}$.

The difference between $\Delta H$ and $\Delta U$ $(\Delta H - \Delta U),$ when the combustion of one mole of heptane $(l)$ is carried out at a temperature $T$ is equal to (in $,RT$)

An ideal gas in a thermally insulated vessel at internal pressure $= P_1$,volume $= V_1$ and absolute temperature $= T_1$ expands irreversibly against zero external pressure,as shown in the diagram. The final internal pressure,volume and absolute temperature of the gas are $P_2, V_2$ and $T_2$,respectively. For this expansion,
$(A) \ q = 0$
$(B) \ T_2 = T_1$
$(C) \ P_2 V_2 = P_1 V_1$
$(D) \ P_2 V_2^\gamma = P_1 V_1^\gamma$

$A$ pure substance (solid,liquid,or gas) of constant composition is taken in a closed container. Select the correct plot if pressure is applied at constant temperature in the absence of non-expansion work.

Calculate the enthalpy change when $50 \ mL$ of $0.01 \ M$ $Ca(OH)_2$ reacts with $25 \ mL$ of $0.01 \ M$ $HCl$. Given that $\Delta H^o_{\text{neutralisation}}$ of strong acid and strong base is $-57.1 \ kJ \ mol^{-1}$. [Assuming that $Ca(OH)_2$ is a strong base]

$A$ gas expands from $3\, dm^3$ to $5.8\, dm^3$ against a constant external pressure of $3\, bar$. The work done during expansion is used to heat $2\, moles$ of water from $290\, K$ to a final temperature of $T\, K$. If the specific heat of water is $4.2\, J\, g^{-1}\, K^{-1}$,then $T = ......\, K$. (in $.6$)