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:

not defined, because pressure is not constant

For the process H 2 O(l) → H 2 O(g) at T=100 ° C and 1 atmosphere pressure, the correct choice is:

∆ S system > 0 and ∆ S surrounding < 0

∆ S system > 0 and ∆ S surrounding > 0

∆ S system < 0 and ∆ S surrounding > 0

∆ S system < 0 and ∆ S surrounding < 0

Chemistry - Thermodynamics - Quiz-1

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

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decrease of free energy
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increase of free energy
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decrease of entropy
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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:

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reversible process
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cyclic process
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isobaric process
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spontaneous process

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

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closed system
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Isolated system
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open system
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None of these

Work done in the reversible adiabatic process is given by:

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2.303 RT log (V₂/V₁)
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$\frac{nR}{(γ - 1)} (T_{2} - T_{1})$
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2.303 RT log(V₁/V₂)
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none of these

Change in enthalpy for reaction,

2H₂O₂(l) $\to$ 2H₂O(l) + O₂(g)

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

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-196 kJ/mol
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+ 196 kJ/mol
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+948 kJ/mol
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-948 kJ/mol

One mole of a non-ideal gas undergoes a change of state (2.0 atm, 3.0 L, 95 K) $\to$ (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:

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40.0
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42.3
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44.0
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not defined, because pressure is not constant

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

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The first law
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Second law
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Third law
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None of the above

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

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Entropy
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Enthalpy
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Gibbs energy
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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:

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W= $- \int P ∆ V$
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W=0
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W= -P $∆$ V
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none of these

Entropy decreases during:

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crystallization of sucrose from solution
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rusting of iron
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melting of ice
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vaporization of camphor

Entropy change of vaporization at constant pressure is given by:

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$∆ S_{(p)} = \frac{∆ Hp}{T}$
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$∆ S_{(v)} = \frac{∆ U_{v}}{T}$
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$∆ S_{(v)} = \frac{∆ H_{v}}{P}$
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None of the above

What is the entropy change for the reaction given below,

2H₂ (g) + O₂ (g) $\to$ 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.

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-318.4 JK^-1mol^-1 .
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318.4 JK^-1mol^-1
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31.84 JK^-1mol^-1
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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 $\to$ 2HCl is:

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30 J K^-1mol^-1
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40 J K^-1mol^-1
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60 J K^-1mol^-1
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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:

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T/(2)^2/3
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T + 2/(3x0.0821)
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T
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T - 3/(2x0.0821)

Which is not a spontaneous process?

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Expansion of gas into the vacuum
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Water flowing downhill
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Heat flowing from a colder body to a hotter body
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Evaporation of water from clothes during drying

The direct conversion of A to B is difficult and thus it is converted by path A $\to$ C $\to$ D $\to$ B. Given

$∆ S_{A \to C} = 50 e . u; ∆ S_{C \to D} = 30 e . u; ∆ S_{B \to D} = 20 e . u .$

Where e.u. is the entropy unit, then $∆ S_{A \to B}$ is:

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+60 e.u
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+100 e.u
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-60 e.u
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-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?

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The $∆$ H for the reaction N₂O₄(g) $⇌$ 2NO₂(g) is +ve
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Paramagnetism increases on heating
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The $∆$ H- $∆$ U at 100 $°$ C is equal to 200 cal
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Dimerisation is reduced on heating

Enthalpy of the reaction,

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

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x>y
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x<y
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x=y
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x $⩾$ y

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

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$∆$ H>T $∆$ S
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$∆$ S= $∆$ H/T
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$∆$ H=T $∆$ S
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All of the above

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

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higher than the initial temperature
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lower than the initial temperature
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the same as the initial temperature
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dependent on the rate of compression

1 liter-atmosphere is equal to:

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101.3 J
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24.206 cal
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101.3 x 10⁷ erg
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All of the above

The standard change is Gibbs energy for the reaction,

H₂O $⇄$ H⁺ + OH^- at 25 $°$ C is:

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100 kJ
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-90 kJ
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90 kJ
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-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)

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9.77 JK^-1mol^-1
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19.73 JK^-1mol^-1
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2930 JK^-1mol^-1
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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:

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2.01 x 10³ J
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+2.81 x 10³ J
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2.01 x 10^-3 J
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+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:

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19.15 JK^-1mol^-1
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16.15 JK^-1mol^-1
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22.15 JK^-1mol^-1
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None of the above

For the process

H₂O(l) $\to$ H₂O(g)

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

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$∆ S_{system} > 0 and ∆ S_{surrounding} > 0$
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$∆ S_{system} > 0 and ∆ S_{surrounding} < 0$
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$∆ S_{system} < 0 and ∆ S_{surrounding} > 0$
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$∆ S_{system} < 0 and ∆ S_{surrounding} < 0$

During an adiabatic process:

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pressure is maintained constant
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gas is isothermally expanded
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there is perfect heat insulation
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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) $\to$ CH₄(g) is

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-17 kcal/mol
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-111 kcal/mol
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-170 kcal/mol
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-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:

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20 cal
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50 cal
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40 cal
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30 cal

For the process:

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

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$∆ G = 0; ∆ S = + ve$
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$∆ G = 0; ∆ S = - ve$
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$∆ G = + ve; ∆ S = 0$
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$∆ G = - ve; ∆ S = + ve$

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Practice Chemistry Quiz Questions and Answers

0:0:1

Practice Chemistry Quiz Questions and Answers

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