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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

Correct Answer :

A. 0


Related Questions

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Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in

A. Increased COP

B. Same COP

C. Decreased COP

D. Increased or decreased COP; depending upon the type of refrigerant

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4

The total change in the enthalpy of a system is independent of the

A. Number of intermediate chemical reactions involved

B. Pressure and temperature

C. State of combination and aggregation in the beginning and at the end of the reaction

D. None of these

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4

The necessary and sufficient condition for equilibrium between two phases is

A. The concentration of each component should be same in the two phases

B. The temperature of each phase should be same

C. The pressure should be same in the two phases

D. The chemical potential of each component should be same in the two phases

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4

What is the value of ln y (where y = activity co-efficient) for ideal gases?

A. Zero

B. Unity

C. Infinity

D. Negative

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4

Dry ice is

A. Moisture free ice

B. Solid helium

C. Solid carbon dioxide

D. None of these

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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

Gibbs free energy (G) is represented by, G = H - TS, whereas Helmholtz free energy, (A) is given by, A = E - TS. Which of the following is the Gibbs-Helmholtz equation?

A. [∂(G/T)/∂T] = - (H/T2)

B. [∂(A/T)/∂T]V = - E/T2

C. Both (A) and (B)

D. Neither (A) nor (B)

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Specific heat of a gas for a reversible adiabatic process is

A. Negative

B. Zero

C. Infinity

D. None of these

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The equilibrium constant for a chemical reaction at two different temperatures is given by

A. Kp2/Kp1 = - (ΔH/R) (1/T2 - 1/T1)

B. Kp2/Kp1 = (ΔH/R) (1/T2 - 1/T1)

C. Kp2/Kp1 = ΔH (1/T2 - 1/T1)

D. Kp2/Kp1 = - (1/R) (1/T2 - 1/T1)

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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

With increase in reduced temperature, the fugacity co-efficient of a gas at constant reduced pressure

A. Increases

B. Decreases

C. Remain same

D. Decreases linearly

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4

Which of the following is not a common refrigerant?

A. Freon-12

B. Ethylene

C. Ammonia

D. Carbon dioxide

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4

Change of heat content when one mole of compound is burnt in oxygen at constant pressure is called the

A. Calorific value

B. Heat of reaction

C. Heat of combustion

D. Heat of formation

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4

Joule-Thomson co-efficient which is defined as, η = (∂T/∂P)H = 1/Cp (∂H/∂T)P, changes sign at a temperature known as inversion temperature. The value of Joule-Thomson co-efficient at inversion temperature is

A. 0

B.

C. +ve

D. -ve

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4

Sublimation temperature of dry ice (solid CO2) is __________ °C.

A. -273

B. 0

C. -78

D. 5

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4

In the equation, PVn = constant, if the value of n = 1, then it represents a reversible __________ process.

A. Isothermal

B. Isobaric

C. Polytropic

D. Adiabatic

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Gibbs-Duhem equation

A. States that n11 + n22 + ....njj = 0, for a system of definite composition at constant temperature and pressure

B. Applies only to binary systems

C. Finds no application in gas-liquid equilibria involved in distillation

D. None of these

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4

Ideal gas law is applicable at

A. Low T, low P

B. High T, high P

C. Low T, high P

D. High T, low P

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An isolated system can exchange __________ with its surroundings.

A. Matter

B. Energy

C. Neither matter nor energy

D. Both matter and energy

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The equation, (d loge PA/d loge xA) = (d loge PA/d loge xB) applicable to a binary solution of components. A and B in equilibrium with their vapors at constant temperature and pressure is called the __________ equation.

A. Van Laar

B. Margules

C. Gibbs-Duhem

D. Gibbs-Duhem-Margules

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4

With increase in temperature, the internal energy of a substance

A. Increases

B. Decreases

C. Remains unchanged

D. May increase or decrease; depends on the substance

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4

Fugacity and pressure are numerically not equal for the gases

A. At low temperature and high pressure

B. At standard state

C. Both (A) and (B)

D. In ideal state

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4

Pick out the wrong statement.

A. The values of (∂P/∂V)T and (∂2P/∂V2)T are zero for a real gas at its critical point

B. Heat transferred is equal to the change in the enthalpy of the system, for a constant pressure, non-flow, mechanically reversible process

C. Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures

D. During a reversible adiabatic process, the entropy of a substance remains constant

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A gas mixture of three components is brought in contact with a dispersion of an organic phase in water. The degree of freedom of the system is

A. 3

B. 4

C. 5

D. 6

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Generation of heat by friction is an example of a/an __________ change.

A. Isothermal

B. Irreversible

C. Adiabatic

D. Reversible

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The unit of fugacity is the same as that of the

A. Pressure

B. Temperature

C. Volume

D. Molar concentration

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__________ law of thermodynamics ascertains the direction of a particular spontaneous process.

A. Zeroth

B. First

C. Second

D. Third

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For a real gas, the chemical potential is given by

A. RT d ln P

B. RT d ln f

C. R d ln f

D. None of these

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4

Choose the condition that must be specified in order to liquify CO2 (triple point for CO2 is - 57°C and 5.2 atm).

A. Pressure must be kept below 5.2 atm

B. Temperature must be kept above - 57°C

C. Pressure must be kept below 5.2 atm. and temperature must be kept above 57°C

D. Pressure and temperature must be kept below 5.2 atm. and - 57°C respectively

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4

Helmholtz free energy (A) is defined as

A. A = H - TS

B. A = E - TS

C. A = H + TS

D. None of these