$A$ $10 \ g$ piece of iron $(C = 0.45 \ J/g \ ^oC)$ at $100 \ ^oC$ is dropped into $25 \ g$ of water $(C = 4.2 \ J/g \ ^oC)$ at $27 \ ^oC$. Find the temperature of the iron and water system at thermal equilibrium in $^oC$.

The molar heats of fusion and vaporisation of benzene are $10.9$ and $31.0 \ kJ \ mol^{-1}$ respectively. The changes in entropy for the solid $\rightarrow$ liquid and liquid $\rightarrow$ vapour transitions for benzene are $x$ and $y \ JK^{-1} \ mol^{-1}$,respectively. The value of $(y-x)$ (in $JK^{-1} \ mol^{-1}$) is (At $1 \ atm$,benzene melts at $5.5^{\circ} C$ and boils at $80^{\circ} C$).

One mole of an ideal monoatomic gas at temperature $T$ expands adiabatically in an insulated flask from $1 \ L$ to $2 \ L$ against an external pressure of $1 \ atm$. What is the final temperature?

The molar heat of neutralization of $NaOH$ with $HCl$ in comparison to that of $KOH$ with $HNO_3$ is:

For an isothermal expansion of $2 \, \text{mol}$ of a gas at $298 \, K$ from $5 \, dm^3$ to $40 \, dm^3$ under constant external pressure,the work done $(W)$ and the reversible work $(W_{rev})$ are,respectively:

The heat change for the following reaction at $298 \ K$ and at constant pressure is $+ 7.3 \ kcal$. $A_2B_{(s)} \to 2A_{(s)} + 1/2 \ B_{2(g)}$,$\Delta H = + 7.3 \ kcal$. The heat change at constant volume would be