“The mass and energy both are conserved in an isolated system”,is the statement of

In the complete combustion of butanol $C_4H_9OH_{(l)}$,if $\Delta H$ is the enthalpy of combustion and $\Delta E$ is the heat of combustion at constant volume,then

For the gaseous reaction $A_{(g)} + 3B_{(g)} \rightarrow 3C_{(g)} + 3D_{(g)}$,the value of $\Delta U = 17 \, Kcal$ at $27 \, ^oC$. Assuming $R = 2 \, cal \, K^{-1} \, mol^{-1}$,the value of $\Delta H$ for the above reaction will be ....... $Kcal$.

In a process,a system performs $238 \ J$ of work on its surroundings by absorbing $54 \ J$ of heat. What is the change in internal energy of the system during this operation (in $J$)?

For which of the following reactions is $\Delta H \neq \Delta U$?

$A$ gas absorbs $150 \ J$ of heat and expands by $300 \ cm^3$ against a constant external pressure of $2 \times 10^5 \ N \ m^{-2}$. What is the change in internal energy $(\Delta U)$ of the system (in $J$)?