Find the constant external pressure required to expand a gas from $2.5 \ L$ to $4.5 \ L$ if the amount of work done is $500 \ J$ at $298 \ K$. (in $bar$)

The heat of reaction at constant pressure is given by

Identify the equation in which the change in enthalpy is equal to the change in internal energy.

One mole of an ideal gas at $300 \ K$ and $20 \ atm$ expands to $2 \ atm$ under isothermal and reversible conditions. The work done by the gas is $-x \ kJ \ mol^{-1}$. The value of $x$ is $(R = 8.3 \ J \ K^{-1} \ mol^{-1})$

An ideal gas undergoes a cyclic transformation starting from the point $A$ and coming back to the same point by tracing the path $A$ $\rightarrow B$ $\rightarrow C$ $\rightarrow D$ $\rightarrow A$ as shown in the three cases above. Choose the correct option regarding $\Delta U$.

For which of the following reactions is $\Delta U = \Delta H$?