Answer:
A. ΔH∘rxn = 21.9 KJ/mol
B. ΔH∘rxn = 103 KJ/mol
C. C2H5OH + 3O2 → 2CO2 + 3H2O
Explanation:
A.
The standard reaction equation is given as:
aA + bB → cC + dD
Its standard enthalpy is given as:
ΔH∘rxn = cΔH∘f(C) + dΔH∘f(D) − aΔH∘f(A) − bΔH∘f(B)
Reaction given to us is:
H2O(l) + CCl4(l) → COCl2(g) + 2HCl(g)
So, its standard enthalpy will be:
ΔH∘rxn = (1)ΔH∘f(CoCl2 (g)) + (2)ΔH∘f(HCl(g)) − (1)ΔH∘f(H2O(l)) − (1)ΔH∘f(CCl4(l))
using the values from table:
ΔH∘rxn = - 218.8 KJ/mol + (2)(- 92.3 KJ/mol) - (- 285.8 KJ/mol) - (- 139.5 KJ/mol)
<u>ΔH∘rxn = 21.9 KJ/mol</u>
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B.
Reaction given to us is:
2A + B ⇌ 2C + 2D
So, its standard enthalpy will be:
ΔH∘rxn = (2)ΔH∘f(C) + (2)ΔH∘f(D) − (2)ΔH∘f(A) − (1)ΔH∘f(B)
using the values from table:
ΔH∘rxn = (2)181 KJ/mol + (2)(- 523 KJ/mol) - (2)(- 225 KJ/mol) - (- 337 KJ/mol)
<u>ΔH∘rxn = 103 KJ/mol</u>
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C.
Balanced equation for combustion of ethanol is:
<u>C2H5OH + 3O2 → 2CO2 + 3H2O</u>
