Problem: Pentaborane-9, B5H9, will combust when exposed to oxygen into B2O3(s) and water at 25°C and 1 atm. Determine the energy in the form of heat released at constant pressure per gram of B5H9, given the following ΔH°f values: B5H9(l), 73.2 kJ•mol-1; B2O3(s), -1263.6 73.2 kJ•mol-1; H2O(l), -285.873.2 kJ•mol-1; H2O(g), -241.818 kJ•mol -1;a) -9000 kJ•g-1b) 145 kJ•g-1c) 8900 kJ•g-1d) -140 kJ•g-1e) -71 kJ•g-1

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Pentaborane-9, B5H9, will combust when exposed to oxygen into B2O3(s) and water at 25°C and 1 atm. Determine the energy in the form of heat released at constant pressure per gram of B5H9, given the following ΔH°f values: B5H9(l), 73.2 kJ•mol-1; B2O3(s), -1263.6 73.2 kJ•mol-1; H2O(l), -285.873.2 kJ•mol-1; H2O(g), -241.818 kJ•mol -1;

a) -9000 kJ•g-1

b) 145 kJ•g-1

c) 8900 kJ•g-1

d) -140 kJ•g-1

e) -71 kJ•g-1

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