For a reaction,$A_{(g)} \to A_{(l)}$; $\Delta H = -3RT$. The correct statement for the reaction is

Which of the following is the correct mathematical expression for the first law of thermodynamics?

$A$ gas expands against a variable pressure given by $P = \frac{20}{V}$ ($P$ in $atm$ and $V$ in $L$). During expansion from volume of $1 \ L$ to $10 \ L$,the gas undergoes an increase in internal energy of $400 \ J$. How much heat is absorbed by gas during expansion (in $J$)? (Given: $1 \ L \cdot atm = 101.3 \ J$)

In a $1 \, L$ container,$2 \, mol$ of $CO$ and $1 \, mol$ of $O_2$ are taken. They react according to the equation: $2CO(g) + O_2(g) \rightarrow 2CO_2(g)$,$\Delta H = -560 \, kJ$. Given that $1 \, atm \cdot L = 0.1 \, kJ$,and the pressure changes from $70 \, atm$ to $40 \, atm$ at $500 \, K$,calculate the value of $\Delta U$ in $kJ$.

$A$ certain system is exothermic by $260 \ kJ$ and does $10 \ kJ$ of work. What is the change in internal energy (in $kJ$)?

When $1 \, \text{mol}$ of a gas is heated at constant volume,the temperature increases from $298 \, K$ to $308 \, K$. If the heat supplied to the gas is $500 \, J$,which of the following statements is correct?