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Thermodynamics and Enthalpy of Formation

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I need some help with this problem, see attached file for full problem description with proper symbols:
2. a) Use only the following data to determine delta H°f for NO2 (g):
- delta H°f for NO (g) is +90.4 kJ/mol
- delta H = -56.6 kJ/mol for the reaction: NO (g) + 1/2 O2 (g) ---> NO2 (g)
b) Find delta H for the reaction: 4 CO (g) + 2 NO2 (g) ----> 4 CO2 (g) + N2 (g)
using only your answer to (a) and the fact that
delta H = -283.0 kJ/mol for the reaction: CO (g) + 1/2 O2 (g)------> CO2 (g)
c) A 10.0-liter vessel contains 5.0 atm of CO and 3.0 atm of NO2 at 25°C. How
much heat (in Joules) will be liberated if this is allowed to react to completion
according to the reaction in part (b)?
d) With Appendix C from your text, calculate H for the combustion of C4H10 (l).

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Solution Summary

This solution gives step-by-step calculations to determine delta H for NO2, conversion of carbon monoxide to carbon dioxide and also how much heat is liberated if a reaction is allowed to react to completion. Full workings and explanations are provided.

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Light energy
(eV )
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(eV )

3.87 no —
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3.89 yes 0
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What is the enthalpy change when 0.2500 moles of B5H9 are combusted?
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n = 1, l = 2, ml = 3, ms = 4

n = 3, l = 2, ml = -2, ms = 1/2

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Substance ΔH ∘ f (kJ/mol)

CF 4 (g)
− 679.9

CH 4 (g)
− 74.8

− 268.61

Keep in mind that the enthalpy of formation of an element in its standard state is zero.
Part A
Calculate the enthalpy change, ΔH ∘ , for the "expansion" of methane:CH 4 (g)→C(g)+4H(g)
Express your answer to one decimal place and include the appropriate units.
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Substance ΔH f ∘ (kJ/mol)


Al(OH) 3 (s)

H 2 O(l)

AlCl 3 (s)

H 2 O(g)

Part A
Determine the enthalpy for this reaction:Al(OH) 3 (s)+3HCl(g)→AlCl 3 (s)+3H 2 O(l)
Express your answer in kilojoules per mole to four significant figures.
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Substance ΔH ∘ f

218 kJ/mol

H 2 (g)
0 kJ/mol

0 kJ/mol

Ba 2+ (aq)
− 538.4 kJ/mol

71 kJ/mol

0 kJ/mol

473 kJ/mol

O 2 (g)
0 kJ/mol

249 kJ/mol

S 2 (g)
129 kJ/mol

Part A
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Express your answer as a chemical equation.
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Substance ΔH ∘ f
(kJ/mol )

ClO 2 (g)
O 2 (g)
O 3 (g)
Part A
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