Work done in the reversible adiabatic process is given by:
1. 2.303 RT log (V2/V1)
2.
3. 2.303 RT log(V1/V2)
4. none of these
Determine the enthalpy change for the specified reaction:
2H2O2(l) 2H2O(l) + O2(g).
(Given the heat of formation of H2O2(l) and H2O(l) are –188 and –286 kJ/mol respectively)
1. | –196 kJ/mol | 2. | +196 kJ/mol |
3. | +948 kJ/mol | 4. | –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:
1. 40.0
2. 42.3
3. 44.0
4. not defined, because pressure is not constant
According to the law, a perfect crystal's entropy is 0 at absolute zero, which is:
1. The first law
2. Second law
3. Third law
4. None of the above
At constant pressure and temperature, the direction of any chemical reaction is one where the...... decrease.
1. Entropy
2. Enthalpy
3. Gibbs energy
4. 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:
1. W=
2. W=0
3. W= -PV
4. none of these
Entropy decreases during:
1. crystallization of sucrose from solution
2. rusting of iron
3. melting of ice
4. vaporization of camphor
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.
1. -318.4 JK-1mol-1 .
2. 318.4 JK-1mol-1
3. 31.84 JK-1mol-1
4. 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:
1. 30 J K-1mol-1
2. 40 J K-1mol-1
3. 60 J K-1mol-1
4. 20 J K-1mol-1
Change in entropy is negative for:
1. Bromine (l)Bromine(g)
2. C(s) + H2O(g) CO(g) + H2(g)
3. N2(g,10 atm)N2(g,1 atm)
4. Fe ( 1mol, 400 K) Fe( 1mol, 300 K)
Which statements are correct?
1. is called Clausius-Clapeyron equation
2. is called Trouton's rule
3. Entropy is a measure of unavailable energy, i.e.,
unavailable energy = entropy x temperature
4. All of the above
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:
1. reversible process
2. cyclic process
3. isobaric process
4. spontaneous process
All the naturally occurring processes, i.e., spontaneous proceed spontaneously in a direction that leads to:
1. decrease of free energy
2. increase of free energy
3. decrease of entropy
4. increase of enthalpy
Warming ammonium chloride with sodium hydroxide in a test tube is an example of:
1. closed system
2. Isolated system
3. open system
4. None of these
Predict which of the following reaction(s) has a positive entropy change?
(i) Ag+ (aq) + Cl-(aq) AgCl(s)
(ii) NH4Cl(g) NH3(g) + HCl(g)
(iii) 2NH3(g)N2(g) + 3H2(g)
(1) i & ii
(2) iii
(3) ii & iii
(4) ii
For given following equations and values, determine the enthalpy of reaction at 298 K for the reaction
C2H4(g) + 6F2(g) 2CF4(g) + 4HF(g)
H2(g) + F2(g) 2HF(g) = -537 kJ
C(s) + 2F2(g) CF4(g) =-680 kJ
2C(s) + 2H2(g) C2H4(g) = 52 kJ
1. -1165
2. -2486
3. +1165
4. +2486
If (C2H4) and (C2H6) are x1 and x2 kcal/mol then heat of hydrogenation of C2H4 is :-
(1) x1 + x2
(2) x1 - x2
(3) x2 - x1
(4) x1 + 2x2
For the reaction, X2O4(l) 2XO2(g)
U = 2.1 kcal, S = 20 cal K-1 at 300 K. Hence, G is
1. 2.7 kcal
2. -2.7 kcal
3. 9.3 kcal
4. -9.3 kcal
The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at 0 °C is:
1. 10.52 cal/(mol K)
2. 21.04 cal/(mol K)
3. 5.260 cal/(mol K)
4. 0.526 cal/(mol K)
The enthalpy and entropy change for the reaction :
Br2 (l) + Cl2 (g) 2BrCl (g)
are 30 kJ mol-1 and 105 J K-1 mol-1 respectively.
The temperature at which the reaction will be in equilibrium is :
1. | 285.7 K | 2. | 273.4 K |
3. | 450.9 K | 4. | 300.1 K |
The temperature of the system decreases in an
(1) Adiabatic compression
(2) Isothermal compression
(3) Isothermal expansion
(4) Adiabatic expansion
Mark the correct statement
1. For a chemical reaction to be feasible, ΔG should be zero
2. Entropy is a measure of order in a system
3. For a chemical reaction to be feasible, ΔG should be positive
4. The total energy of an isolated system is constant
Which of the following is not a state function
(1) Internal energy
(2) Enthalpy
(3) Work
(4) Entropy
The work done in ergs for the reversible expansion of one mole of an ideal gas from a volume of 10 liters to 20 liters at 25°C is -
1.
2.
3.
4.
An ideal gas expands in volume from 1 × 10–3 m3 to 1 × 10–2 m3 at 300 K against a constant pressure of 1 × 105 Nm–2. The work done is [AIEEE 2004]
(1) 270 kJ
(2) –900 kJ
(3) –900 J
(4) 900 kJ
The mixing of non-reacting gases is generally accompanied by
1. Decrease in entropy
2. Increase in entropy
3. Change in enthalpy
4. Change in free energy
An irreversible process occuring isothermally in an isolated system leads to
(1) Zero entropy
(2) An increase in the total entropy of the system
(3) A decrease in the total entropy of the system
(4) None of these
The enthalpy and entropy change for a chemical reaction are
–2.5 × 103 cal and 7.4 cal deg–1 respectively. Predict the reaction at 298 K is
1. Spontaneous
2. Reversible
3. Irreversible
4. Non-spontaneous
The entropy changed involved in the conversion of 1 mole of liquid water at 373 K to vapour at the same temperature will be [MP PET 2002]
(1) 0.119 kJ
(2) 0.109 kJ
(3) 0.129 kJ
(4) 0.120 kJ
When a liquid boils, there is [JIPMER 2002]
(1) An increase in entropy
(2) A decrease in entropy
(3) An increase in heat of vaporization
(4) An increase in free energy
For a carnot engine, the source is at 500 K and the sink at 300 K. What is efficiency of this engine
(1) 0.2
(2) 0.4
(3) 0.6
(4) 0.3
A solution of 500 ml of 0.2 M KOH and 500 ml of 0.2 M HCl is mixed and stirred; the rise in temperature is T1. The experiment is repeated using 250 ml each of solution, the temperature raised is T2. Which of the following is true
(1) T1 = T2
(2) T1 = 2T2
(3) T1 = 4T2
(4) T2 = 9T1
The heat of formation of HCl(g) from the reaction
H2(g) + Cl2(g) ; is
1. +44 kcal
2. -44 kcal
3. +22 kcal
4. -22 kcal
The heat of neutralisation of HCl by NaOH is -55.9 kJ/mole. If the heat of neutralisation of HCN by NaOH is -12.1 kJ/mole, then energy of dissociation of HCN is-
1. -43.8 kJ
2. 43.8 kJ
3. 68 kJ
4. -68 kJ
In which case of mixing of a strong acid and a base, each of 1(N) concentration, temperature-increase is the highest ?
1. 20 ml acid and 30 ml alkali
2. 10 ml acid and 40 ml alkali
3. 25 ml acid and 25 ml alkali
4. 35 ml acid and 15 ml alkali
The heats of neutralisation of four acids A, B, C and D are -13.7, -9.4, -11.2 and -12.4 kcal respectively when they are neutralised by a common base. The acidic character obeys the order :
1. A>B>C>D
2. A>D>C>B
3. D>C>B>A
4. D>B>C>A
If a process is both endothermic and spontaneous, then :
1.
2.
3.
4.
The bond energies of C=C and C-C at 298 K are 590 and 331 kJ mol-1 respectively. The enthalpy of polymerization per mole of ethylene is
1. -70 kJ
2. -72 kJ
3. 72 kJ
4. -68 kJ
The gas absorbs 100 J heat and is simultaneously compressed by a constant external pressure of 1.50 atm from 8 lit. to 2 lit. in volume. Hence will be-
1. -812 J
2. 812 J
3. 1011 J
4. 911 J
The standard heat of combustion of Al is -837.8 kJ mol-1 at which of the following releases 250 kcal of heat ?
1. The reaction of 0.624 mol of Al
2. The formation of 0.624 mol of Al2O3
3. The reaction of 0.312 mol of Al
4. The formation of 0.150 mol of Al2O3
Following reaction occurs at :
2NO(g) , (1 × 10-5 atm) + Cl2(g), ( 1×10-2 atm) ⇌ 2NOCl(g), ( 1×10- 2 atm) ∆Go is-
1. -45.65 kJ
2. -28.53 kJ
3. -22.82 kJ
4. -57.06 kJ
For the reaction :
1. 2.7 kcal
2. -2.7 kcal
3. 9.3 kcal
4. -9.3 kcal
The bond energies of , C-H, H-H, and C=C are 198, 98, 103 and145 kcal respectively.
The enthalpy change of the reaction would be-
1. 48 kcal
2. 96 kcal
3. -40 kcal
4. -152 kcal
The enthalpies of formation of CO2(g) and CO(g) at 298 K are in the ratio 2.57 : 1. For the reaction,
1. -150.6 kJ mol-1
2. -302.63 kJ mol-1
3. -130.2 kJ mol-1
4. -141.8 kJ mol-1
The enthalpies of the following reactions are shown alongwith.
Calculate the O-H bond energies for the hydroxyl radical.
1. 223.18 kJ mol-1
2. 423.38 kJ mol-1
3. 513.28 kJ mol-1
4. 113.38 kJ mol-1