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Moderate

Free Energy Change Calculation

APCHEM-LXNI1O

When chlorine gas and phosphorus gas is bubbled through water to create $PCl_3$, what is the free energy change of the system per mole at standard conditions?

Substance at 25 $^{\circ}C$, 1 atm $ \Delta H_f$ (kJ/mol) $ \Delta G_f$ (kJ/mol) $ \Delta S_f$ (kJ/mol-K)
$O_{2(g)}$ 0 0 205
$H_2O_{(I)}$ -286 -237 69.9
$P_{2(g)}$ 144 104 218
$PCl_3$ -288 -270 312
$POCl_3$ -542 -502 325
$S_{(S)}$ 0 0 31.9
$SO_{2(g)}$ -270 -300 249
$SO_{3(g)}$ -395 -370 256
$Cl_{2(g)}$ 0 0 223
$Cl^{-}_{(aq)}$ -167 -131 56.5
A

-644 kJ/mol

B

-374 kJ/mol

C

-251 kJ/mol

D

-243 kJ/mol