$A$ system performs mechanical work equal to $15 \ kJ$ and loses $2 \ kJ$ of heat to the surroundings. What is the change in internal energy of the system (in $kJ$)?

For the reaction $C_3H_8(g) + 5O_2(g) \rightarrow 3CO_2(g) + 4H_2O(l)$,the value of $\Delta H - \Delta U$ is:

Calculate $\Delta H$ for the following reaction at $25^{\circ} C$.
$NH_2CN_{(g)} + \frac{3}{2} O_{2_{(g)}} \longrightarrow N_{2_{(g)}} + CO_{2_{(g)}} + H_2O_{(l)}$
$(\Delta U = -740.5 \ kJ, R = 8.314 \ J \ K^{-1} \ mol^{-1})$

$q$ and $w$ are both ....... functions and $q + w$ is a ....... function.

The first law of thermodynamics is only:

For the reaction $Ag_2O_{(s)} \rightarrow 2Ag_{(s)} + \frac{1}{2}O_{2(g)}$,which of the following is true?