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AP EAMCET2002ChemistryThermodynamics (C)

Calculate the heat of combustion (in kJ ) of methane from the following data: (i) C _ (graphite) +2 H ₂(g) CH ₄(g) H=-74.8 (ii) C _ (graphite) + O ₂(g) CO ₂(g) H=-393.5 (iii) H ₂(g)+1 / 2 O ₂(g) H ₂ O (l) H=-286.2 kJ

Options

  1. A-891.9
  2. B-816.3
  3. C-965.9
  4. D-1040.7

Correct answer

A. -891.9

Step-by-step solution

CH ₄(g)+2 O ₂(g) CO ₂(g)+2 H ₂ O (l) H= ? To get this equation reverse equation (i) write equation (ii) as it is, multiply equation (iii) by 2 and add all these equations, we will get H gathered H=+74.8+(-393.5)+(-286.2 2) =-891.1 ~kJ gathered

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