P2C.4 From the following data, determine A,H° for diborane, B,H,(g), at 298 K: (1) B,H,(g) + 3 O,(g) → B,O,(s) + 3 H,O(g) A,H° =-1941kJ mol %3D (2) 2 B(s)+O,(g) → B,O,(s) A,H° =-2368kJ mol (3) H,(g) +0,(g) → H,O(g) A,H° =-241.8kJ mol %3D

Calculate ΔH°298 for the process Co3O4(s)⟶3Co(s) + 2O2(g)from the following information:Co(s) + (1)/(2)O2(g)⟶CoO(s)           ΔH°298 = −237.9kJ3CoO(s) +(1)/(2)O2(g)⟶Co3O4(s)    ΔH°298 = −177.5kJ

Use the following values of standard entropies and ΔSrxn to determine the missing standard entropies.

2) Which statement is true for the decomposition of 2NH3 (l)  ⟶ N2 (g) + 3H2 (g) ___________ (ΔU & ΔE mean the same).  (a)ΔH is less than ΔU because of the pressure-volume work done by the gaseous products. (b)ΔH is greater than ΔU because the pressure is constant. (c)ΔH is greater than ΔU because of the pressure-volume work done by the gaseous products. (d)ΔH is less than ΔU because the atmosphere does pressure-volume work done by the gaseous products. (e)ΔH is equal ΔU because both are state functions.

3. Given the following equations and AHO values, determine the heat of reaction (kJ) at 298 K for the reaction: 2 SO2(g) + 2 P(s) + 5 Cl2(g) → 2 SOC12 (1) + 2 POC13(1) SOC12(1)+ H₂O(1)→→ SO2(g) + 2 HCl(g) PC13(1)+1/2 O2(g) → POC13(1) P(s) + 3/2 Cl2(g) → PC13(1) 4 HCl(g) + O2(g) →2 Cl2(g) + 2 H₂O(1) ΔΗ° = +10.3 kJ ΔΗ° = -325.7 kJ ΔΗ = -306.7 kJ ΔΗ = -202.6 kJ

Calculate the value of ΔHm − ΔUm for the reaction N2(g) + 3 H2(g) → 2 NH3(g) at 298 K.

Determine the enthalpy change for the reaction: S03 (g) + H20(g) → H2SO4 (1) Given: i. H2SO4 (1) → H2SG) + 2 02 (9); ΔΗ 1236.4 kJ %3D ii. SO3 + H20(1) H2S(9) + 2 02 (9); ΔΗ1086.7 ky (g) iii. H20(1) → H20(g); AH° = 40.7 kJ

Element X has an enthalpy of fusion of 59.2 kJ mol-1 at its melting point (684°C). Calculate ΔSsys for the process,X(l) → X(s)At 1 bar and 684°C. Express your answer in units of J mol-1 K-1 to 3 significant figures.