Identify the reaction for which $\Delta H \neq \Delta E$ :

The temperature of a system decreases in which of the following processes?

For the combustion of sucrose $(C_{12}H_{22}O_{11})$ at $250\,^oC$,which of the following is true?

An ideal gas is subjected to a cyclic process involving four thermodynamic states. The amounts of heat $(Q)$ and work $(W)$ involved in each of these processes are:
$Q_1 = 6000 \, J, Q_2 = -5500 \, J, Q_3 = -3000 \, J, Q_4 = 3500 \, J$
$W_1 = 2500 \, J, W_2 = -1000 \, J, W_3 = -1200 \, J, W_4 = x \, J$
The ratio of the net work done by the gas to the total heat absorbed by the gas is $\eta$. The values of $|x|$ and $\eta$ respectively are:

Calculate the change in internal energy of the system if work done by the system is $18 \ J$ and absorbs heat $50 \ J$ in a particular reaction. (in $J$)

If a system absorbs $30 \ kJ$ of heat and performs $12 \ kJ$ of work on the surroundings,what is the increase in internal energy of the system (in $kJ$)?