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AP EAMCET201823 Apr 2018Evening ShiftChemistryThermodynamics (C)Actual

If enthalpy of combustion of carbon to CO ₂( ~g ) is -394.0 ~kJ ~mol ⁻¹ , the enthalpy change for the formation of 17.6 ~g of CO ₂ from carbon and dioxygen at the same temperature in kJ is

Options

  1. A-157.6
  2. B315.2
  3. C157.6
  4. D-315.2

Correct answer

A. -157.6

Step-by-step solution

Reaction for combusion is C + O ₂ CO ₂, H =-394 ~kJ ~mol ⁻¹ Molar mass of CO ₂=12+(2 10) and =44 ~g 44 ~g of formation of CO ₂ gives heat =-394.0 ~kJ 17.6 ~g of formation of CO ₂ , gives heat = -394 17.6 44 =-157.6 ~kJ .

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