What is the change in internal energy when a system releases $8 \ kJ$ of heat and performs $660 \ J$ of work on the surroundings (in $J$)?

In a cylinder,$1.0 \, \text{kcal}$ of heat is added to $1.2 \, \text{L}$ of $O_2$ gas at a constant pressure of $1 \, \text{atm}$. The volume changes to $1.5 \, \text{L}$. Calculate the change in internal energy $(\Delta U)$ for this process. (in $, \text{kcal}$)

$A$ gas expands isothermally against a constant external pressure of $1 \ bar$ from $10 \ dm^3$ to $20 \ dm^3$ by absorbing $800 \ J$ of heat from the surroundings. Calculate the value of $\Delta U$. (in $J$)

Work done in vaporisation of one mole of water at $373 \ K$ and the pressure of $1 \ atm$ is approximately (for ideal gas)......$J$

Given below are two statements.
Statement-$I$ : Adiabatic work done is positive when work is done on the system and internal energy of the system increases.
Statement-$II$ : No work is done during free expansion of an ideal gas.
In the light of the above statements,choose the correct answer from the options given below.

Which of the following relations is correct for the reaction $S(s) + O_2(g) \rightarrow SO_2(g)$?