Enthalpy change question
hey, hope you're doing well!
I am not sure about the answer, can you check out please?
thank you!
(iii) Calculate the standard enthalpy change of formation, ∆fH ө, of hydrogen sulfide using the enthalpy change for Reaction 1, and the standard enthalpy changes of combustion below.
Substance ∆cH ө / kJ mol−1
S(s) −296.8
H2(g) −285.8
2H2S(g) + 3O2(g) --> 2SO2(g) + 2H2O(l) ∆rH = –1125 kJ mol−1 Reaction 1
my answer:
S(s) + H2(g) ------------- > H2S(g)
\ /
\ /
> combustion products <
∆fH of H2S = -582.6 + 562.5 = - 20.1 KJmol-1
At first I got -40.2 KJmol-1, unfortunately i don't have the mark scheme.
I am not sure about the answer, can you check out please?
thank you!
(iii) Calculate the standard enthalpy change of formation, ∆fH ө, of hydrogen sulfide using the enthalpy change for Reaction 1, and the standard enthalpy changes of combustion below.
Substance ∆cH ө / kJ mol−1
S(s) −296.8
H2(g) −285.8
2H2S(g) + 3O2(g) --> 2SO2(g) + 2H2O(l) ∆rH = –1125 kJ mol−1 Reaction 1
my answer:
S(s) + H2(g) ------------- > H2S(g)
\ /
\ /
> combustion products <
∆fH of H2S = -582.6 + 562.5 = - 20.1 KJmol-1
At first I got -40.2 KJmol-1, unfortunately i don't have the mark scheme.
(edited 3 years ago)
Original post by Orchard2
hey, hope you're doing well!
I am not sure about the answer, can you check out please?
thank you!
(iii) Calculate the standard enthalpy change of formation, ∆fH ө, of hydrogen sulfide using the enthalpy change for Reaction 1, and the standard enthalpy changes of combustion below.
Substance ∆cH ө / kJ mol−1
S(s) −296.8
H2(g) −285.8
2H2S(g) + 3O2(g) --> 2SO2(g) + 2H2O(l) ∆rH = –1125 kJ mol−1 Reaction 1
my answer:
S(s) + H2(g) ------------- > H2S(g)
\ /
\ /
> combustion products <
∆fH of H2S = -582.6 + 562.5 = - 20.1 KJmol-1
At first I got -40.2 KJmol-1, unfortunately i don't have the mark scheme.
I am not sure about the answer, can you check out please?
thank you!
(iii) Calculate the standard enthalpy change of formation, ∆fH ө, of hydrogen sulfide using the enthalpy change for Reaction 1, and the standard enthalpy changes of combustion below.
Substance ∆cH ө / kJ mol−1
S(s) −296.8
H2(g) −285.8
2H2S(g) + 3O2(g) --> 2SO2(g) + 2H2O(l) ∆rH = –1125 kJ mol−1 Reaction 1
my answer:
S(s) + H2(g) ------------- > H2S(g)
\ /
\ /
> combustion products <
∆fH of H2S = -582.6 + 562.5 = - 20.1 KJmol-1
At first I got -40.2 KJmol-1, unfortunately i don't have the mark scheme.
If given enthalpies of combustion, formula is: (sum of reactants) - (sum of products).
Original post by Orchard2
hey, hope you're doing well!
I am not sure about the answer, can you check out please?
thank you!
(iii) Calculate the standard enthalpy change of formation, ∆fH ө, of hydrogen sulfide using the enthalpy change for Reaction 1, and the standard enthalpy changes of combustion below.
Substance ∆cH ө / kJ mol−1
S(s) −296.8
H2(g) −285.8
2H2S(g) + 3O2(g) --> 2SO2(g) + 2H2O(l) ∆rH = –1125 kJ mol−1 Reaction 1
my answer:
S(s) + H2(g) ------------- > H2S(g)
\ /
\ /
> combustion products <
∆fH of H2S = -582.6 + 562.5 = - 20.1 KJmol-1
At first I got -40.2 KJmol-1, unfortunately i don't have the mark scheme.
I am not sure about the answer, can you check out please?
thank you!
(iii) Calculate the standard enthalpy change of formation, ∆fH ө, of hydrogen sulfide using the enthalpy change for Reaction 1, and the standard enthalpy changes of combustion below.
Substance ∆cH ө / kJ mol−1
S(s) −296.8
H2(g) −285.8
2H2S(g) + 3O2(g) --> 2SO2(g) + 2H2O(l) ∆rH = –1125 kJ mol−1 Reaction 1
my answer:
S(s) + H2(g) ------------- > H2S(g)
\ /
\ /
> combustion products <
∆fH of H2S = -582.6 + 562.5 = - 20.1 KJmol-1
At first I got -40.2 KJmol-1, unfortunately i don't have the mark scheme.
-296.8 - 285.8 + 1125/2 = -20.1 kJ
Original post by Orchard2
hey, hope you're doing well!
I am not sure about the answer, can you check out please?
thank you!
(iii) Calculate the standard enthalpy change of formation, ∆fH ө, of hydrogen sulfide using the enthalpy change for Reaction 1, and the standard enthalpy changes of combustion below.
Substance ∆cH ө / kJ mol−1
S(s) −296.8
H2(g) −285.8
2H2S(g) + 3O2(g) --> 2SO2(g) + 2H2O(l) ∆rH = –1125 kJ mol−1 Reaction 1
my answer:
S(s) + H2(g) ------------- > H2S(g)
\ /
\ /
> combustion products <
∆fH of H2S = -582.6 + 562.5 = - 20.1 KJmol-1
At first I got 40.2 KJmol-1, unfortunately idon't have the mark scheme.
I am not sure about the answer, can you check out please?
thank you!
(iii) Calculate the standard enthalpy change of formation, ∆fH ө, of hydrogen sulfide using the enthalpy change for Reaction 1, and the standard enthalpy changes of combustion below.
Substance ∆cH ө / kJ mol−1
S(s) −296.8
H2(g) −285.8
2H2S(g) + 3O2(g) --> 2SO2(g) + 2H2O(l) ∆rH = –1125 kJ mol−1 Reaction 1
my answer:
S(s) + H2(g) ------------- > H2S(g)
\ /
\ /
> combustion products <
∆fH of H2S = -582.6 + 562.5 = - 20.1 KJmol-1
At first I got 40.2 KJmol-1, unfortunately idon't have the mark scheme.
You can draw out a Hess Cycle if it helps.
2H2S(g) + 3O2(g) --> 2SO2(g) +2H2O(l)
\ / /
2S(s), 2H2(g), 3O2(g)
Filling in the relevant enthalpy changes and calculating will yield you -20.1kJ mol-1, which is the correct answer.
You may have got -40.2kJ mol-1 as your answer if you forgot that it makes 2 moles of H2S, so of course you simply need to divide by 2 for your final answer.
2H2S(g) + 3O2(g) --> 2SO2(g) +2H2O(l)
\ / /
2S(s), 2H2(g), 3O2(g)
Filling in the relevant enthalpy changes and calculating will yield you -20.1kJ mol-1, which is the correct answer.
You may have got -40.2kJ mol-1 as your answer if you forgot that it makes 2 moles of H2S, so of course you simply need to divide by 2 for your final answer.
(edited 9 months ago)
Quick Reply
Related discussions
- enthalpy change of sol more or less exo
- Chemistry ocr a level enthalpy
- Chemistry Olympiad question
- As level chemistry
- enthalpy change of sol
- Chemistry question- enthalpy of formation
- Chemistry question- energetics
- Chemistry help pleaseee !!!! 🙏🙏🙏
- Hess law and combustion
- A-level chem enthalpy question
- Enthaly Change and Hess's Law
- Enthalpy change
- Energetics Alevel chem multiple choice
- Hess cycle question
- 2Al(s) Fe2O3(s) → Al2O3(s) 2Fe(s), struggling with this question
- Bond Enthalpies Question
- Chemistry help ( please 😭😭 )
- enthalpy change of combustion alchols
- Isaac physics - essential pre-uni chemistry F3.4 question help pls!!!!!!!!!!!!!!!!!!
- Enthalpy change question help !!
Latest
Trending
Last reply 1 week ago
Im confused about this chemistry question, why does it form these productsTrending
Last reply 1 week ago
Im confused about this chemistry question, why does it form these products
