Question

Question 10 Calculate AHpxn for the reaction below given: AH+ (AsH3(g) - 66.4 kJ/mol; AH [HAS HgAsO4(aq) + 4H2(g) => AsH3(g) + 4H2O(1) Selected Answer: Correct Answer: D. 685.2 kJ B.-172.2 kJ Question 11 Data: 2Fe(s) + O2(g) => 2FeO(s) AH = -544.0 kJ 4Fe(s) + 3020) => 2Fe2O3(s) AH = -1648,4 kJ Fe3O4(s) => Fe(s) +2026) AH = +1118.4 kJ Given the data above, determine the heat of reaction, AH, for the reaction below: Reaction: Fe2O3(s) + FeO(s) => Fe3O4(s) Selected Answer: Correct Answer: A. -1074.0 kJ B.-22.2 kJ Question 12 The following statements concerning petroleum are all true except: Selected Answer: A. All of its hydrocarbon chains contain the same number of carbon ator Correct Answer: A. All of its hydrocarbon chains contain the same number of carbon aton Monday, October 28, 2019 2:14:58 PM CDT MacBook Air.

Answer 1

Given

H3AsO4(aq) + 4H2(g) → AsH3(g) + 4H2O(l)

ΔHf [AsH3(g)] = 66.4 kJ/mol

ΔHf [H3AsO4(aq)] = -904.6 kJ/mol

ΔHf [H2O(l)] = -285.8 kJ/mol

ΔHf [H2 (g)] = 0 kJ/mol

Now

ΔH°rxn = (∑ΔHf(products)) - (∑ΔHf(reactants))

=( ΔHf [AsH3(g)]+ 4*ΔHf [H2O(l)]) - (ΔHf [H3AsO4(aq)]+ 4*ΔHf [H2])

= (66.4 kJ/mol+4*-285.8 kJ/mol) – (-904.6 kJ/mol+0)

= -1076.8 kJ/mol + 904.6 kJ/mol

= -172.2 kJ/mol

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Given

2Fe(s) + O2(g) --> 2 FeO(s) ΔH=-544.0 kJ ------------------(1)

4Fe(s) + 3O2(g) --> 2 Fe2O3(s) ΔH= -1648.4 kJ------------------(2)

Fe3O4(s) --> 3Fe(s) + 2O2(g) ΔH= +1118.4 kJ------------------(3)

Now

reverse (1) and divide by

FeO(s) --> Fe(s) + 1/2O2(g) ΔH = 544.0/2 kJ --------------(4)

reverse (2) and divide by 2

Fe2O3(s) --> 2Fe(s) + 3/2O2(g) ΔH= 1648.4/2 kJ --------------(5)

reverse (3)

3Fe(s) + 2O2(g) --> Fe3O4(s) ΔH= -1118.4 kJ --------------(6)

Add (4) (5) (6)

FeO(s) --> Fe(s) + 1/2O2(g) ΔH = 272.0 kJ

Fe2O3(s) --> 2Fe(s) + 3/2O2(g) ΔH= 824.2 kJ

3Fe(s) + 2O2(g) --> Fe3O4(s) ΔH= -1118.4 kJ

Now

FeO(s) + Fe2O3(s) --> Fe3O4(s)

ΔH= 272.0 kJ + 824.2 kJ -1118.4 kJ

= -22.2 kJ