Given that H, (g) + F, (g) –→ 2 HF(g) AHixn -546.6 kJ 2 H, (g) + O,(g) 2 H, O(1) AHixn -571.6 kJ calculate the value of AHxn for 2F, (g) + 2H,O(1) –→ 4 HF(g) + O,(g) > ΔΗΚ rxn

What is the significance of the sign of ΔHºrxn?

If a system has 5.00×102 kcal5.00×102 kcal of work done to it, and releases 5.00×102 kJ5.00×102 kJ of heat into its surroundings, what is the change in internal energy (Δ? or Δ?)(ΔE or ΔU) of the system?

PCI5(s) can be prepared by the reaction PCI3(1) + Cl2(g) - PCI5(s). Calculate the enthalpy change (in kJ) that accompanies the production of 100.0 g of PCI5(s) by the above reaction, given the following data. P4(s) + 6 Cl2(g) - 4 PC|3(1) AH° = -1280 kJ per mole of P4(s) %3D P4(s) + 10 Cl2(g) – 4 PCI5(s) ΔΗ AH° = -1774 kJ per mole of P4(s) +59.3 -59.3 +124 -124 -258

When 0.430 g of biphenyl (C12H10)(  undergoes combustion in a bomb calorimeter, the temperature rises from 26.8 ∘C to 29.7 ∘C   Find  ΔErxn for the combustion of biphenyl. The heat capacity of the bomb calorimeter, determined in a separate experiment, is 5.86 kJ/∘C Express the energy in kilojoules per mole to three significant figures.

Calculate the internal energy change (ΔE) for a system undergoing an exothermic process in which 24.9 kJ of heat flows out of the system and where 13.6 kJ of work is done on the system. Show all work and units in your answer, Ex: (-12.4) + (-3.0) = -15.4 kJ.