Calculate the change in enthalpy in a chemical reaction when work done is $-800 \ J$ and increase in internal energy is $600 \ J$. (in $J$)

At a certain temperature, T(K), during a process, 500 J is absorbed by the system and work of 200 J is done by the system. Then change in internal energy of the system is:

At $300 \ K$,the enthalpy change for the reaction $C_3H_8(g) + 5O_2(g) \rightarrow 3CO_2(g) + 4H_2O(l)$ is $-2800 \ kJ \ mol^{-1}$. Calculate the internal energy change $(\Delta U)$ for the reaction at the same temperature.

Assuming that water vapour is an ideal gas,the internal energy change $(\Delta U)$ when $1\, mol$ of water is vaporised at $1\, bar$ pressure and $100\, ^{\circ}C$,(given: molar enthalpy of vaporisation of water at $1\, bar$ and $373\, K = 41\, kJ\, mol^{-1}$ and $R = 8.3\, J\, mol^{-1}\, K^{-1}$) will be .............. $kJ\, mol^{-1}$

When a system is supplied with $60 \ J$ of heat,it performs $15 \ J$ of work. The change in the internal energy of the system is ......... $J$.

Two litres of an ideal gas at a pressure of $10 \ atm$ expands isothermally at $25^{\circ}C$ into a vacuum until its total volume is $10 \ litres$. How much heat is absorbed and how much work is done in the expansion?