Physical Chemistry MCQ with Answers

Physical Chemistry MCQ with Answers

186) For a reaction at 25^oC, enthalpy change ΔH and entropy change ΔS are −11 x 10³ and 10⁵ J⁄mol K respectively, then which of the following statements is true?

Answer is:

Non−spontaneous reaction

187) Enthaply of carbon, hydrogen and ethyl alcohol on combsution at 25^oC are −94, −68.4 and −327 kcal⁄mol, then the formation enthalpy of ethyl alcohol will be:

Answer is:

−66.2 kcal⁄mol

188) The work of expansion for a system is 500 cal. The heat given to the system is 80 cal. The change in internal energy in the process will be:

Answer is:

−420 cal

Explanation:

ΔE = q + w

189) The heat capacity for a bomb calorimeteris 500 J⁄^oC. In an experiment, in the combustion of 0.1 gm methane, the temperature rise was by 2^oC. What is the value of ΔE per mol?

Answer is:

+160 KJ

190) For a certain reaction, the change in enthalpy and the change in entropy are 40.63 kJ⁄mol and 100 J⁄K. What is the value of ΔG at 27^oC? Also, indicate whether the reaction is possible or not.

Answer is:

+10630 J⁄mol; not possible

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