Question

Use the ΔH°f and ΔH°rxn information provided to calculate ΔH°f for IF: ΔH°f (kJ/mol) IF7(g) + I2(g) → IF5(g) + 2 IF(g)

ΔH°rxn = -89 kJ

IF7(g) -941

IF5(g) -840

Answers:

(a) -190 KJ/mol

(b) 101 KJ/mol

(c) 24 KJ/mol

(d) -95 KJ/mol

(e) -146 KJ/mol

Answer #1

**IF _{7}(g) + I_{2}(g) → IF_{5}(g)
+ 2 IF(g) , ΔH°_{rxn} = - 89 kJ**

ΔH°rxn = (sum of ΔH°f products) - (sum of ΔH°f reactants)

given ΔH°rxn = -89 kJ

ΔH°f (IF7) = -941 kJ

ΔH°f(I_{2}) = 0 (elements in their standard state have
zero ΔH°f)

ΔH°f(IF5) = -840 kJ

ΔH°f(IF) = ?

so ΔH°rxn = [ ΔH°f(IF5) + 2 X ΔH°f(IF) ] - [ ΔH°f(IF7) +
ΔH°f(I_{2}) ]

-89 = [ -840 + 2 X ΔH°f(IF) ] - [ -941 + 0 ]

-89 = -840 + 2 X ΔH°f(IF) + 941

-89 = 101 + 2 X ΔH°f(IF)

2 X ΔH°f(IF) = -89 - 101 = -190

ΔH°f(IF) = -190/2 = -95

Answer is **(d) -95 kJ/ mol**

Use the ΔH°f and ΔH°rxn information provided to calculate ΔH°f
for IF: ΔH°f (kJ/mol) IF7(g) + I2(g) → IF5(g) + 2 IF(g) ΔH°rxn =
-89 kJ IF7(g) -941 IF5(g) -840

Use the following information to find ΔH°f
of gaseous HCl:
N2(g) + 3H2(g) →
2NH3(g)
ΔH°rxn = - 91.8 kJ
N2(g) + 4H2(g) +
Cl2(g) →
2NH4Cl(s)
ΔH°rxn = - 628.8 kJ
NH3(g) + HCl(g) →
NH4Cl(s)
ΔH°rxn = - 176.2 kJ

Given the following data, calculate, ΔH rxn, ΔS rxn, and Δ rxn,
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What direction is the spontaneity of this system?
Mg (s) +HCl (aq) <---> H2 (g) +
MgCl2 (aq)
Mg(s)
HCl(aq)
H2 (g)
MgCl2(aq)
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0
-167.2
0
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S°(J/(mol K)
130.7
56.5
32.7
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HCl(g) given the standard enthalpies of formation
(ΔH⁰f ) shown in the table below. (Include the sign of the
value in your answer.)
kJ
Compound
ΔH⁰f
(kJ/mol)
TiCl4(g)
−763.2
H2O(g)
−241.8
TiO2(s)
−944.0
HCl(g)
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Use standard enthalpies of formation to calculate ΔH∘rxn for the
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1.Using the enthalpies of formation given below, calculate
ΔH°rxn in kJ, for the following reaction.
Report your answer to two decimal places in standard
notation.
H2S(g) + 2O2(g) → SO3(g) +
H2O(l)
H2S (g): -20.60 kJ/mol
O2 (g): 0.00 kJ/mol
SO3 (g): -395.77 kJ/mol
H2O (l): -285.83 kJ/mol
2. Calculate the amount of heat absorbed/released (in kJ) when
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Report your answer to two decimal places, and use appropriate signs
to...

Given the values of ΔH∘rxn, ΔS∘rxn, and
T below, determine ΔSuniv.
Part A
ΔH∘rxn= 117 kJ , ΔS∘rxn=− 263 J/K ,
T= 291 K .
ΔSuniv=
−1.3•102
J/K
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Incorrect; Try Again; 3 attempts remaining
Part B
ΔH∘rxn=− 117 kJ , ΔS∘rxn= 263 J/K ,
T= 291 K .
ΔSuniv=
J/K
SubmitMy AnswersGive
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Part C
ΔH∘rxn=− 117 kJ , ΔS∘rxn=− 263 J/K ,
T= 291 K.
ΔSuniv=
J/K
SubmitMy AnswersGive
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Part D
ΔH∘rxn=− 117 kJ ,...

Given the values of ΔH∘rxn, ΔS∘rxn, and
T below, determine ΔSuniv.
Part A
ΔH∘rxn= 115 kJ , ΔS∘rxn=− 263 J/K ,
T= 301 K .
ΔSuniv=
J/K
SubmitMy AnswersGive
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Part B
ΔH∘rxn=− 115 kJ , ΔS∘rxn= 263 J/K ,
T= 301 K .
ΔSuniv=
J/K
SubmitMy AnswersGive
Up
Part C
ΔH∘rxn=− 115 kJ , ΔS∘rxn=− 263 J/K ,
T= 301 K .
ΔSuniv=
J/K
SubmitMy AnswersGive
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Part D
ΔH∘rxn=− 115 kJ , ΔS∘rxn=− 263 J/K ,
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m =
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Express your answer using five significant figures.
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