Calculate ∆H° for the reaction,&nbs

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 Multiple Choice QuestionsMultiple Choice Questions

61.

The yield of the product in the reaction

A2(g) + 2B(g) C(g) + Q kJ would be higher at

  • high temperature and high pressure

  • high temperature and low pressure

  • low temperature and high pressure

  • low temperature and low pressure


62.

Given that Hf(H) = 218 kJ / mol, express the H-H bond energy in kcal/mol.

  • 52.15

  • 911

  • 104

  • 52153


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63.

Calculate H° for the reaction, Na2O(s) + SO3(g)  Na2SO4(g) given the following:(A) Na(s) +H2O(l)  NaOH(s) + 12H2(g) ;H°= -146 kJ(B) Na2SO4(s) +H2O(l) 2 NaOH(s) + SO3(g); H°=+ 418 kJ(C) 2 Na2O(s) +2 H2(g) 4Na(s) + 2H2O(l); H°= +259 kJ

  • +823 kJ

  • -581 kJ

  • -435 kJ

  • +531 kJ


B.

-581 kJ

By, '2A +C2- B', we getNa2O + SO3  Na2SO4;H= -2 ×146+ 2592-418H= -580.5 -581 kJ


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64.

If an endothermic reaction occurs spontaneously at constant temperature (T) and pressure (p), then which of the following is true?

  • G > 0

  • H < 0

  • S > 0

  • S < 0


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65.

A spontaneous process is one in which the system suffer

  • no energy change

  • a lowering of free energy

  • a lowering of entropy

  • an increase in internal energy


66.

When a solid melts reversibly :

  • H decreases

  • G increases

  • E decreases

  • S increases


67.

Enthalpy is equal to :

  • T2(G/T)TP

  • -T2(G/T)TP

  • T2(G/T)TV

  • -T2(G/T)TV


68.

Condition for spontaneity in an isothermal process is

  • A + W < 0

  • G + U <0

  • A + U>0

  • G -U<0


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69.

2C(s) + 2O2(g)  2CO2(g);              H= -787 kJ ....(i)H2(g) + 12O2(g)  H2O (l);              H = -286 kJ ...(ii)C2H2(g) + 212O2(g)  2CO2(g) + H2O (l) ;  H= -1310 kJ ...(iii)

The heat of formation of acetylene is :

  • -1802 kJ

  • +1802 kJ

  • +237 kJ

  • -800 kJ


70.

The standard molar heat of formation of ethane, CO2 and water (l) are -21.1, -94.1 and -68.3 kcal respectively. The standard molar heat of combustion of ethane will be

  • -372 kcal

  • 162 kcal

  • -240 kcal

  • 183.5 kcal


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