If the initial internal energy of a system is $U_1$,and it absorbs $450 \ J$ of heat from the surroundings and performs $600 \ J$ of work,what will be the final internal energy of the system?

$A$ gas present in a cylinder expands against a constant pressure of $1 \, atm$ from a volume of $2 \, L$ to a volume of $6 \, L$. In doing so,it absorbs $800 \, J$ of heat from the surroundings. The change in internal energy of the process is ..... $J$.

For the reaction,$C_3H_{8(g)} + 5O_{2(g)} \to 3CO_{2(g)} + 4H_2O_{(l)}$ at constant temperature,$\Delta H - \Delta E$ is

$\Delta U$ is equal to

For the reaction $CO_{(g)} + \frac{1}{2} O_{2(g)} \rightarrow CO_{2(g)}$ at constant temperature and pressure,which of the following statements is correct?

$\Delta_{vap} H^{\ominus}$ for water is $+40.49 \ kJ \ mol^{-1}$ at $1 \ bar$ and $100^{\circ} C$. The change in internal energy for this vaporization under the same conditions is . . . . . . . . . . $kJ \ mol^{-1}$. (Integer answer) (Given $R = 8.3 \ J \ K^{-1} \ mol^{-1}$)