Chemistry - Thermochemistry Question with Solution | TestHub
ChemistryThermochemistryEnthalpy of solution/dilution/hydrationEasy2 minQB
ChemistryEasysingle choice
Study the following thermodynamic data given by E. H. P. Cordfunke, A. S. Booji and M. Y. Furkalionk.
(i) DyCl3(s) → DyCl3(aq., in 4.0 M-HCl); ΔH0 = -180.06 kJ/mol
(ii) Dy(s) + 3HCl(aq, 4.0 M) → DyCl3(aq, in 4.0 M-HCl) + 3/2 H2(g); ΔH° = -699.43 kJ/mol
(iii) 1/2 H2(g) + 1/2 Cl2(g) → HCl(aq, 4.0 M); ΔH° = -158.31 kJ/mol
What is ΔHf0 of DyCl3(s) from these data?
Options:
Answer:
B
Solution:
The target reaction is:
Dy(s) + 3/2 Cl2(g) tarrow DyCl3(s)
To achieve this, we combine the given reactions as follows: (ii) + 3 × (iii) - (i).
The enthalpy of formation, Δ Hf, is calculated as:
Δ Hf = -699.43 + 3(-158.31) - (-180.06)
Δ Hf = -699.43 - 474.93 + 180.06
Δ Hf = -994.30 kJ/mol
This corresponds to option (b).
Stream:JEESubject:ChemistryTopic:ThermochemistrySubtopic:Enthalpy of solution/dilution/hydration
⏱ 2mℹ️ Source: QB
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