i.e., w = 0
$\because\text{w}=-\text{P}_\text{ext}\times\Delta\text{V}=0\times\Delta\text{V}=0$
$\Delta\text{U}=\text{q}+\text{w}$
q = 0 because gas chamber is insulated
$\therefore\Delta\text{U}=0+0=0$
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
$3\text{C(graphite)}+4\text{H}_2\text{O}\overrightarrow{\ \ \ \ \ \ \ }\ \text{C}_3\text{H}_8(\text{g})$
$\Delta_\text{f}\text{H}^\circ$ for propane, C3H8(g) is -103.8kJ mol-1
Given: $\text{S}^\circ_\text{m}\text{C}_3\text{H}_8(\text{g})=270.2\text{JK}^{-1}\text{mol}^{-1},$ $\text{S}^\circ_\text{m}\text{C}_{(\text{graphite})}=5.70\text{JK}^{-1}\text{mol}^{-1}$ and $\text{S}^\circ_\text{m}\text{H}_2(\text{g})=130.7\text{JK}^{-1}\text{mol}^{-1}$| Elements | $\Delta H _1$ | $\Delta H _2$ | $\Delta_{ eg } H$ |
| I | 520 | 7300 | - 60 |
| II | 419 | 3051 | - 48 |
| III | 1681 | 3374 | - 328 |
| IV | 1008 | 1846 | - 295 |
| V | 2372 | 5251 | + 40 |
| VI | 738 | 1451 | - 40 |
4d, 4f, 5s, 5p
5p, 5d, 5f, 6s, 6p
$\Delta\text{U}^\ominus$of combustion of methane is – X kJ mol–1. The value of $\Delta\text{H}^\ominus$ is:
$=\Delta\text{U}^\ominus$
$>\Delta\text{U}^\ominus$
$<\Delta\text{U}^\ominus$
$=0$