Energetics / Thermochemistry

$313.5 \, J$

$62.7 \, J$

$750.0 \, J$

$3135 \, J$

$J \cdot K^{-1}$

$kJ \cdot mol^{-1}$

$J \cdot g^{-1} \cdot K^{-1}$

$kJ \cdot g^{-1}$

The reaction is exothermic and $\Delta H$ is positive.

The reaction is endothermic and $\Delta H$ is positive.

The reaction is exothermic and $\Delta H$ is negative.

The reaction is endothermic and $\Delta H$ is negative.

$-150 \text{ kJ}$

$-300 \text{ kJ}$

$+300 \text{ kJ}$

$+75 \text{ kJ}$

$C(s) + 4H(g) + O(g) \rightarrow CH_3OH(l)$

$CH_4(g) + \frac{1}{2}O_2(g) \rightarrow CH_3OH(l)$

$C(graphite) + 2H_2(g) + \frac{1}{2}O_2(g) \rightarrow CH_3OH(l)$

$CO(g) + 2H_2(g) \rightarrow CH_3OH(l)$

$\Delta H_1 - \Delta H_2$

$\Delta H_2 - \Delta H_1$

$\Delta H_1 + \Delta H_2$

$(\Delta H_1 + \Delta H_2) / 2$

Solid

Liquid

Gaseous

Aqueous

$\Delta H = \sum (\text{bond enthalpies of bonds broken}) - \sum (\text{bond enthalpies of bonds formed})$

$\Delta H = \sum (\text{bond enthalpies of bonds formed}) - \sum (\text{bond enthalpies of bonds broken})$

$\Delta H = \sum \Delta H_f^{\theta}(\text{products}) - \sum \Delta H_f^{\theta}(\text{reactants})$

$\Delta H = \sum (\text{bond enthalpies of reactants}) + \sum (\text{bond enthalpies of products})$

Bond breaking is endothermic ($\Delta H$ is positive) and bond formation is exothermic ($\Delta H$ is negative).

Bond breaking is exothermic ($\Delta H$ is negative) and bond formation is endothermic ($\Delta H$ is positive).

Both bond breaking and bond formation are endothermic processes.

Both bond breaking and bond formation are exothermic processes.

Larger ionic radii and lower ionic charges

Smaller ionic radii and lower ionic charges

Larger ionic radii and higher ionic charges

Smaller ionic radii and higher ionic charges

Enthalpy of ionization

Enthalpy of atomization of sodium

Lattice enthalpy

Enthalpy of formation

$Mg^{2+}$

$Na^{+}$

$Ca^{2+}$

$K^{+}$

$N_{2}(g) + 3H_{2}(g) \rightarrow 2NH_{3}(g)$

$C(s) + O_{2}(g) \rightarrow CO_{2}(g)$

$2CO(g) + O_{2}(g) \rightarrow 2CO_{2}(g)$

$Ba(OH)_{2} \cdot 8H_{2}O(s) + 2NH_{4}SCN(s) \rightarrow Ba(SCN)_{2}(aq) + 10H_{2}O(l) + 2NH_{3}(g)$

The reaction is spontaneous at all temperatures.

The reaction is non-spontaneous at all temperatures.

The reaction is only spontaneous at high temperatures.

The reaction is only spontaneous at low temperatures.

$kJ \cdot mol^{-1}$

$J \cdot K^{-1} \cdot mol^{-1}$

$kJ \cdot K \cdot mol^{-1}$

$J \cdot mol^{-1}$