| ⇦ | 
| ⇨ |
Heat of combustion ΔH for C(s) , H₂(g)and CH₄(g) are -94, -68 and -213 kcal/mol. Then ΔH for C(s) + 2H₂(g) → CH₄(g)is
Options
(a) -17 kcal
(b) -111kcal
(c) -170 kcal
(d) -85 kcal
Correct Answer:
-17 kcal
Explanation:
(i) C(s) + O₂ = CO₂ ; ΔH(i) = -94 kcal/mol,
(ii) 2H₂ + O₂ = 2H₂O ; ΔH(ii) = -68 x 2 kcal/mol,
(iii) CH₄ + 2O₂ = CO₂ + 2H₂O ; ΔH(iii) = -213 kcal/mol,
(iv) C(s) + 2H₂(g) = CH₄(g) ; ΔH(iv) = ?,
By applying Hess’s law we can compute ΔH(iv), (i) + (ii) – (iii), we have
C + O₂ + 2H₂ + O₂ – CH₄ – 2O₂ = CO₂ + 2H₂ O – CO₂ – 2H₂ O,
C+ 2H₂ = CH₄,
Therefore ΔH(iv) = ΔH(i) + ΔH(ii) – ΔH(iii) = (-94 – 68 x 2 + 213 ) kcal = -17 kcal.
Related Questions: - If avagadro number is changed what changes
- Biochemical oxygen Demand ,(BOD) is a measure of organic material present in water
- The standard electrode potential is measured by
- Hexoses and pentoses are
- ArH + N₂ + H₃PO₃ + HX are the products of the following reaction
Topics: Thermodynamics
(179)
Subject: Chemistry
(2512)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- If avagadro number is changed what changes
- Biochemical oxygen Demand ,(BOD) is a measure of organic material present in water
- The standard electrode potential is measured by
- Hexoses and pentoses are
- ArH + N₂ + H₃PO₃ + HX are the products of the following reaction
Topics: Thermodynamics (179)
Subject: Chemistry (2512)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
18000+ students are using NEETLab to improve their score. What about you?
Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.
Share this page with your friends
Leave a Reply