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 $kJ$)?

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 change in internal energy equals

Which of the following statements is true regarding the universe according to the laws of thermodynamics?

One mole of an ideal gas expands isothermally and reversibly from $10 \ dm^3$ to $20 \ dm^3$ at $300 \ K$. $\Delta U$,$q$ and work done in the process respectively are $:$ Given $: R=8.3 \ J \ K^{-1} \ mol^{-1}$,$\ln 10=2.3$,$\log 2=0.30$,$\log 3=0.48$

Observe the following reaction: $ABO_{3(s)} \xrightarrow{1000 \ K} AO_{(s)} + BO_{2(g)}$. $\Delta_{r} H$ for this reaction is $x \ kJ \ mol^{-1}$. What is its $\Delta_{r} U$ (in $kJ \ mol^{-1}$) at the same temperature? $(R = 8.3 \ J \ mol^{-1} \ K^{-1})$