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4

For an ideal gas, the activity co-efficient is

A. Directly proportional to pressure

B. Inversely proportional to pressure

C. Unity at all pressures

D. None of these

Correct Answer :

C. Unity at all pressures


Related Questions

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4

A two stage compressor is used to compress an ideal gas. The gas is cooled to the initial temperature after each stage. The intermediate pressure for the minimum total work requirement should be equal to the __________ mean of P1 and P2. (where, P1 and P2 are initial and final pressures respectively)

A. Logarithmic

B. Arithmetic

C. Geometric

D. Harmonic

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4

What happens in a reversible adiabatic compression?

A. Heating occurs

B. Cooling occurs

C. Pressure is constant

D. Temperature is constant

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4

Fugacity is a measure of the

A. Escaping tendencies of the same substance in different phases of a system

B. Relative volatility of a mixture of two miscible liquids

C. Behaviour of ideal gases

D. None of these

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4

Pick out the wrong statement.

A. At constant pressure, solubility of a gas in a liquid diminishes with rise in temperature

B. Normally, the gases which are easily liquefied are more soluble in common solvents

C. The gases which are capable of forming ions in aqueous solution are much more soluble in water than in other solvents

D. At constant pressure, solubility of a gas in a liquid increases with rise in temperature

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4

A system is said to be at equilibrium, if the entropy of the system has reached __________ value.

A. Minimum

B. Zero

C. Maximum

D. None of these

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4

Which of the following is not an extensive property?

A. Free energy

B. Entropy

C. Refractive index

D. None of these

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4

Heat of formation of an element in its standard state is

A. 0

B. < 0

C. > 0

D. A function of pressure

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4

The expression for entropy change given by, ΔS = - nR ln (P2/P1), holds good for

A. Expansion of a real gas

B. Reversible isothermal volume change

C. Heating of an ideal gas

D. Cooling of a real gas

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4

Heating of water under atmospheric pressure is an __________ process.

A. Isochoric

B. Isobaric

C. Adiabatic

D. Isothermal

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4

Internal energy of an element at 1 atm and 25° C is __________ kcal/kg.mole.

A. 0

B. 273

C. 25

D. None of these

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4

The equation, PV = nRT, is best obeyed by gases at

A. Low pressure & high temperature

B. High pressure & low temperature

C. Low pressure & low temperature

D. None of these

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4

One mole of nitrogen at 8 bar and 600 K is contained in a piston-cylinder arrangement. It is brought to 1 bar isothermally against a resisting pressure of 1 bar. The work done (in Joules) by the gas is

A. 30554

B. 10373

C. 4988.4

D. 4364.9

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4

Minimum number of phases that exists in a system is 1. Number of chemical species in a colloidal system is

A. 1

B. 2

C. 3

D. 4

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4

Mollier diagram is a plot of

A. Temperature vs. enthalpy

B. Temperature vs. enthalpy

C. Entropy vs. enthalpy

D. Temperature vs. internal energy

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4

For an ideal gas, the internal energy depends upon its __________ only.

A. Molecular size

B. Temperature

C. Volume

D. Pressure

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4

Degree of freedom of a system consisting of a gaseous mixture of H2 and NH3 will be

A. 0

B. 1

C. 2

D. 3

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4

An isentropic process is carried out at constant

A. Volume

B. Pressure

C. Temperature

D. All (A), (B) and (C)

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4

A solid metallic block weighing 5 kg has an initial temperature of 500°C. 40 kg of water initially at 25°C is contained in a perfectly insulated tank. The metallic block is brought into contact with water. Both of them come to equilibrium. Specific heat of block material is 0.4 kJ.kg-1. K-1. Ignoring the effect of expansion and contraction and also the heat capacity to tank, the total entropy change in kJ.kg-1, K-1 is

A. -1.87

B. 0

C. 1.26

D. 3.91

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4

Pick out the wrong statement

A. Phase rule variables are intensive properties

B. Heat and work are both state function

C. The work done by expansion of a gas in vacuum is zero

D. CP and CV are state function

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4

Solid and liquid phases of a substance are in equilibrium at the

A. Critical temperature

B. Melting point

C. Freezing point

D. Both (B) and (C)

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4

Which of the following is not an intensive property?

A. Molar heat capacity

B. Internal energy

C. Viscosity

D. None of these

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4

When liquid and vapour phase of multi-component system are in equilibrium (at a given temperature and pressure), then chemical potential of each component is

A. Same in both the phases

B. Zero in both the phases

C. More in vapour phase

D. More in liquid phase

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4

Gibbs free energy at constant pressure and temperature under equilibrium conditions is

A.

B. 0

C. Maximum

D. Minimum

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4

A refrigeration cycle is the same as a __________ cycle,

A. Turbine

B. Heat engine

C. Reversed heat engine

D. None of these

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4

A gas shows deviation from ideal behaviour at

A. Low pressure and high temperature

B. Low pressure and low temperature

C. Low temperature and high pressure

D. High temperature and high pressure

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4

Variation of equilibrium pressure with temperature for any two phases of a given substances is given by the __________ equation.

A. Gibbs-Duhem

B. Maxwell's

C. Clapeyron

D. None of these

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4

The freezing point of a liquid decreases when the pressure is increased, if the liquid __________ while freezing.

A. Contracts

B. Expands

C. Does not change in volume

D. Either (A), (B) or (C)

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4

Lenz's law results from the law of conservation of

A. Mass

B. Momentum

C. Energy

D. None of these

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4

A refrigerator may be termed as a

A. Heat pump

B. Heat engine

C. Carnot engine

D. None of these

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4

Cv is given by

A. (∂E/∂T)V

B. (∂E/∂V)T

C. (∂E/∂P)V

D. (∂V/∂T)P