$2.2016 \ g$ of acetaldehyde produced $13.95 \ kcal$ of heat on combustion in $O_2$. Calculate the heat of combustion of $CH_3CHO$ in $kcal \ mol^{-1}$.

The heat of neutralisation will be highest in

The enthalpy change during a reaction does not depend on .......

If $C$ (diamond) $\rightarrow C$ (graphite) $+ X \ kJ \ mol^{-1}$,$C$ (diamond) $+ O_{2(g)} \rightarrow CO_{2(g)} + Y \ kJ \ mol^{-1}$,and $C$ (graphite) $+ O_{2(g)} \rightarrow CO_{2(g)} + Z \ kJ \ mol^{-1}$,at constant temperature,then which of the following relations is correct?

$CuSO_{4(s)} + 5 H_2O_{(\ell)} \rightarrow CuSO_4 \cdot 5 H_2O_{(s)} ; \Delta H = -x \ kJ$. The value of $\Delta H$ represents:

If enthalpies of formation of $C_2H_{4(g)}$,$CO_{2(g)}$ and $H_2O_{(l)}$ at $25 \ ^\circ C$ and $1 \ atm$ pressure are $52$,$-394$ and $-286 \ kJ \ mol^{-1}$ respectively,the enthalpy of combustion of $C_2H_{4(g)}$ will be.....$kJ \ mol^{-1}$.