The work done during combustion of 9 × 10-2 kg of ethane, C

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

81.

Find the correct equation

  • E2 - E1 - H2 + H1 = n2RT - n1RT

  • E2 - E1 - H2 - H1 = n2RT - n1RT

  • H2 - H1 - E2 + E1 = n2RT - n1RT

  • H2 - H1 - E2 - E1 = n2RT - n1RT


82.

Assuming enthalpy of combustion of hydrogen at 273 K is -286 kJ and enthalpy of fusion of ice at the same temperature to be +6.0 kJ, calculate enthalpy change during formation of 100 g of ice.

  • +1622 kJ

  • - 1622 kJ

  • +292 kJ

  • - 292 kJ


83.

For which among the following reactions, change in entropy is less than zero?

  • Sublimation of iodine

  • Dissociation of hydrogen

  • Formation of water

  • Thermal decomposition of calcium carbonate


84.

Which among the following is a feature of adiabatic expansion?

  • V < 0

  • U < 0

  • U > 0

  • T = 0


Advertisement
85.

What is the amount of work done when two moles of ideal gas is compressed from a volume of 1m3 to 10 dm3 at 300 K against a pressure of 100 kPa?

  • 99 kJ

  • -99kJ

  • 114.9 kJ

  • -114.9 kJ


Advertisement

86.

The work done during combustion of 9 × 10-2 kg of ethane, C2H6 (g) at 300 K is (Given R = 8.314 J deg-1 mol-1, atomic mass C = 12, H= 1).

  • 6.236 kJ

  • -6.236 kJ

  • 18.71 kJ

  • -18.71 kJ


C.

18.71 kJ

Work done in a chemical reaction, 

W = ngRT

where, ng = number of moles of gaseous products - number of moles of gaseous reactants.

Combustion of ethane is-

C2H6 (g) + 72O2 (g) → 2CO2 (g) + 3H2O (l)

ng = 2 - 4.5 = -2.5

W = (2.5 mol) (8.314 JK-1 mol-1) × 300 K

    = 6235.5 kJ = 6.2355 J

Now, 1 mole of C2H6 = 30 gm of C2H6 = 6.2355 kJ

Work done for combustion of 30 gm of C2H= 6.2355 kJ

 Work done for combustion of 90 gm of C2H

6.2355 × 9030 

= 18.7065 kJ = 18.71 kJ


Advertisement
87.

The first law of thermodynamics for isothermal process is

  • q = -W

  • U = W

  • U = qv

  • U = -qv


88.

Identify the invalid equation

  • H = ΣHproducts - ΣHreactants

  • H = U + pV

  • H°(reaction) = ΣH°(products bonds) - ΣH°(reactant bonds)

  • H = U + nRT


Advertisement
89.

For the process A (1, 0.05 atm, 32°C) → A (g, 0.05 atm, 32°C)

The correct set of thermodynamic parameters is

  • G = 0 and S = -ve

  • G = 0 and S = +ve

  • G = +ve and S = 0

  • G = -ve and S = 0


90.

The standard enthalpy of formation of H2O (l) and Fe2O3 (s) are respectively -286 kJ mol-1 and -824 kJ mol-1. What is the standard enthalpy change for the following reaction?

Fe2O3 (s) + 3H2 (g) → 3H2O (l) + 2Fe (s)

  • -538 kJ mol-1

  • +538 kJ mol-1

  • -34 kJ mol-1

  • +34 kJ mol-1


Advertisement