The temperature of the system decreases in an

Which of the following statements is correct?

$A$ gas expands from a volume of $1 \text{ dm}^3$ to $1.25 \text{ dm}^3$ against a constant external pressure of $1 \text{ bar}$. Calculate the change in internal energy $(\Delta U)$ if $150 \text{ J}$ of heat is supplied to the system. (in $\text{ J}$)

For the gaseous reaction,$N_2O_4(g) \to 2NO_2(g)$,which of the following relations is correct?

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?

$A$ gas expands isothermally from $10 \, dm^3$ to $20 \, dm^3$ at a constant external pressure of $1 \, atm$. If it absorbs $800 \, J$ of heat from the surroundings,what is the value of $\Delta U$ in $J$ for this process?