All the naturally occurring processes, i.e., spontaneous proceed spontaneously in a direction that leads to:

  • decrease of free energy                     

  • increase of free energy

  • decrease of entropy                           

  • increase of enthalpy

A gaseous system changes from state A(P1, V1, T1) to B(P2,V2,T2), B to C(P3, V3, T3) and finally from C to A. The whole process may be called:

  • reversible process                           

  • cyclic process

  • isobaric process                               

  • spontaneous process

Warming ammonium chloride with sodium hydroxide in a test tube is an example of:

 

  • closed system

  • Isolated system

  • open system

  • None of these

Work done in the reversible adiabatic process is given by:

  • 2.303 RT log (V2/V1)                     

  •  nR (γ-1)(T2-T1)

  • 2.303 RT log(V1/V2)                     

  • none of these

Change in enthalpy for reaction,

2H2O2(l) 2H2O(l) + O2(g)

If the heat of formation of H2O2(l) and H2O(l) are -188 and -286 kJ/mol respectively is -          

  • -196 kJ/mol             

  • + 196 kJ/mol

  • +948 kJ/mol             

  • -948 kJ/mol

One mole of a non-ideal gas undergoes a change of state (2.0 atm, 3.0 L, 95 K)(4.0 atm, 5.0 L, 245 K) with a change in internal energy, U = 30.0 L atm. The change in enthalpy (H) of the process in L atm is:

  • 40.0

  • 42.3

  • 44.0

  • not defined, because pressure is not constant

At absolute zero, the entropy of a perfect crystal is zero. This is........... of thermodynamics.

  • The first law               

  • Second law

  • Third law             

  • None of the above

At constant pressure and temperature, the direction of any chemical reaction is one where the...... decrease.

  • Entropy               

  • Enthalpy

  • Gibbs energy       

  • None of the above

The work done by a mass less piston in causing an expansion V (at constant temperature), when the opposing pressure, P is variable, is given by:

  • W= -PV               

  • W=0

  • W= -PV                     

  • none of these

Entropy decreases during:

  • crystallization of sucrose from solution

  • rusting of iron

  • melting of ice

  • vaporization of camphor

Entropy change of vaporization at constant pressure is given by:

  •  S(p)= HpT

  •  S(v)=UvT

  •  S(v)= HvP

  • None of the above

What is the entropy change for the reaction given below, 

2H2 (g) + O2 (g) 2H2O(l)

at temperature 300 K? Standard entropies of H2 (g), O2(g) and H2O(l) are 126.6, 201.20 and 68.0 JK-1mol-1 respectively.

  • -318.4 JK-1mol-1                           .

  • 318.4 JK-1mol-1 

  • 31.84 JK-1mol-1                             

  • none of these

If S° for H2, Cl2 and HCl are 0.13, 0.22 and 0.19 kJ K-1mol-1 respectively. The total change in standard entropy for the reaction, H2 + Cl2 2HCl is:

  • 30 J K-1mol-1                         

  • 40 J K-1mol-1

  • 60 J K-1mol-1                         

  • 20 J K-1mol-1

When one mole of monoatomic ideal gas at TK undergoes reversible adiabatic change under a constant external pressure of 1 atm changes volume from 1 litre to 2 litre. The final temperature in kelvin would be:

  • T/(2)2/3                                         

  • T + 2/(3x0.0821)

  • T                                                   

  • T - 3/(2x0.0821)

Which is not a spontaneous process?

  • Expansion of gas into the vacuum

  • Water flowing downhill

  • Heat flowing from a colder body to a hotter body

  • Evaporation of water from clothes during drying

The direct conversion of A to B is difficult and thus it is converted by path ACDB. Given

SAC=50 e.u; SCD=30 e.u; SBD=20 e.u.

Where e.u. is the entropy unit, then SAB is:

  • +60 e.u                                       

  • +100 e.u

  • -60 e.u                                       

  • -100 e.u

In a flask, colourless N2O4(g) is in equilibrium with brown coloured NO2(g). At equilibrium when the flask is heated to 100°C, the brown colour deepens and on cooling it becomes less coloured. Which statement is incorrect about this observation?

  • The H for the reaction N2O4(g) 2NO2(g) is +ve

  • Paramagnetism increases on heating

  • The H-U at 100°C is equal to 200 cal

  • Dimerisation is reduced on heating

Enthalpy of the reaction,

 CH4(g) + 1/2 O2(g) CH3OH (l), is negative. If the enthalpy of combustion of CH4 and CH3OH are x and y respectively, then which relation is correct?                                 

  • x>y         

  • x<y         

  • x=y           

  • xy

In the reaction, H and S both are positive. The condition under which the reaction would not be spontaneous is -

  •  H>TS                             

  •  S=H/T

  •  H=TS                               

  • All of the above

When an ideal gas is compressed adiabatically and reversibly, the final temperature is:

  • higher than the initial temperature

  • lower than the initial temperature

  • the same as the initial temperature

  • dependent on the rate of compression

1 liter-atmosphere is equal to:

  • 101.3 J                           

  • 24.206 cal

  • 101.3 x 107 erg               

  • All of the above

The standard change is Gibbs energy for the reaction,

H2OH+ + OH- at 25°C is:

  • 100 kJ                         

  • -90 kJ

  • 90 kJ                           

  • -100 kJ

The entropy change in the fusion of one mole of a solid melting at 27°C  is  -       

(the latent heat of fusion is 2930 J mol-1)                                                                                   

  • 9.77 JK-1mol-1               

  • 19.73 JK-1mol-1               

  • 2930 JK-1mol-1               

  • 108.5 JK-1mol-1          

The maximum work done in expanding 16 g oxygen at 300 K and occupying a volume of 5 dm3 isothermally until the volume becomes 25 dm3 is:

  • 2.01 x 103 J                       

  • +2.81 x 103 J

  • 2.01 x 10-3 J                     

  • +2.01 x 10-6 J

1 mole of an ideal gas at 25°C is subjected to expand reversibly ten times of its initial volume. The change in entropy of expansion is:

  • 19.15 JK-1mol-1                         

  • 16.15 JK-1mol-1

  • 22.15 JK-1mol-1                         

  • None of the above

For the process

H2O(l) H2O(g)

 at T=100°C and 1 atmosphere pressure, the correct choice is:

  •  Ssystem>0 and Ssurrounding>0

  •  Ssystem>0 and Ssurrounding<0

  •  Ssystem<0 and Ssurrounding>0

  •  Ssystem<0 and Ssurrounding<0

 During an adiabatic process:

  • pressure is maintained constant

  • gas is isothermally expanded

  • there is perfect heat insulation

  • the system changes heat with surroundings

Heat of combustion H° for C(s), H2(g) and CH4(g) are -94, -68 and -213 kcal/mol. Then, H° for 

C(s) + 2H2(g) CH4(g) is                                                                 

  • -17 kcal/mol                         

  • -111 kcal/mol

  • -170 kcal/mol                       

  • -85 kcal/mol

If 50 calorie are added to a system and system does work of 30 calorie on surroundings, the change in internal energy of system is:

  • 20 cal                             

  • 50 cal

  • 40 cal                             

  • 30 cal

For the process:

H2O(l)[1 bar, 373 K] H2O(g)[1 bar, 373 K] the correct set of thermodynamic parameters are:

  •  G=0; S=+ve

  •  G=0; S=-ve

  •  G=+ve; S=0

  •  G=-ve; S=+ve

0:0:1


Answered Not Answered Not Visited Correct : 0 Incorrect : 0

Practice Chemistry Quiz Questions and Answers