Calculate the change in internal energy of the system if $20 \ kJ$ work is done on the system and it releases $10 \ kJ$ heat in a particular reaction. (in $kJ$)

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 $J$)

Give the mathematical expression for the first law of thermodynamics.

One mole of an ideal gas is allowed to expand reversibly and adiabatically from a temperature of $27\,^{\circ}C$. If the work done during the process is $3\, kJ$,then the final temperature of the gas is $(C_v = 20\, J/K)$ .....$K$

The law of conservation of energy states that

According to the first law of thermodynamics,which of the following is correct? (Where $q =$ heat supplied to the system and $W =$ work done by the system)