In a closed insulated container,a liquid is stirred with a paddle to increase its temperature. In this process,which of the following is true?

Consider the same expansion,but this time against a constant external pressure of $1 \ atm$.

Assertion : For an isothermal reversible process $Q = -W$,i.e.,work done by the system equals the heat absorbed by the system.
Reason : Enthalpy change $(\Delta H)$ is zero for an isothermal process.

Three moles of an ideal gas are compressed isothermally from $60 \ L$ to $20 \ L$ using a constant external pressure of $5 \ atm$. The heat exchange $Q$ for the compression is $....... \ L \cdot atm$.

$A$ certain mass of an ideal gas absorbs $80 \ kJ$ heat and the gas is expanded from $2 \ L$ to $10 \ L$ at a constant pressure of $25 \ bar$. What is $\Delta U$ for the gas in the process in $kJ$? $(1 \ bar-L = 100 \ J)$

When $1 \ mol$ of ice melts at $0 \ ^oC$ and a constant pressure of $1 \ atm$,the system absorbs $1440 \ cal$ of heat. If the molar volumes of ice and water are $0.0196 \ L$ and $0.0180 \ L$ respectively,calculate the change in internal energy $(\Delta U)$ of the system in $cal$.