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4

First law of thermodynamics is mathematically stated as

A. dQ = dE + dW

B. dQ = dE - dW

C. dE = dQ + dW

D. dW = dQ + dE

Correct Answer :

A. dQ = dE + dW


Related Questions

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4

Entropy of an ideal gas depends upon its

A. Pressure

B. Temperature

C. Both (A) & (B)

D. Neither (A) nor (B)

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4

As the entropy of the universe is increasing, day by day, the work producing capacity of a heat engine is

A. Not changed

B. Decreasing

C. Increasing

D. Data sufficient, can't be predicted

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4

The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same.

A. Kinematic viscosity

B. Work

C. Temperature

D. None of these

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4

Which of the following non-flow reversible compression processes require maximum work?

A. Adiabatic process

B. Isothermal process

C. Isobaric process

D. All require same work

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4

The equation, Cp - Cv = R, is true for __________ gas.

A. No

B. Any real

C. Only ideal

D. Both (B) and (C)

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4

One ton of refrigeration capacity is equivalent to the heat removal rate of

A. 50 kcal/hr

B. 200 BTU/hr

C. 200 BTU/minute

D. 200 BTU/day

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4

Pick out the wrong statement.

A. Minimum number of degree of freedom of a system is zero

B. Degree of freedom of a system containing a gaseous mixture of helium, carbon dioxide and hydrogen is 4

C. For a two phase system in equilibrium made up of four non-reacting chemical species, the number of degrees of freedom is 4

D. Enthalpy and internal energy change is zero during phase change processes like melting, vaporisation and sublimation

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4

Pick out the Clausius-Clapeyron equation from the following:

A. dP/dT = ΔH/TΔV

B. ln P = - (ΔH/RT) + constant

C. ΔF = ΔH + T [∂(ΔF)/∂T]P

D. None of these

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4

Claude's liquefaction process employs the cooling of gases by

A. Expansion in an engine

B. Following a constant pressure cycle

C. Throttling

D. None of these

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4

y = specific heat ratio of an ideal gas is equal to

A. Cp/Cv

B. Cp/(CP-R)

C. 1 + (R/CV)

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

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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

A gas can be liquefied by pressure alone only, when its temperature is __________ its critical temperature.

A. Less than

B. More than

C. Equal to or higher than

D. Less than or equal to

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4

Which of the following is not a unit of the equilibrium constant Kp? (where, Δx = number of moles of products number of moles of reactants)

A. (atm)Δx, when Δx is negative

B. (atm)Δx, when Δx is positive

C. Dimensionless, when Δx = 0

D. (atm)Δx2, when Δx > 0

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4

(∂T/∂P)H is the mathematical expression for

A. Specific heat at constant pressure (Cp)

B. Specific heat at constant volume (Cv)

C. Joule-Thompson co-efficient

D. None of these

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4

Work done in an adiabatic process between two states depends on the

A. Rate of heat transmission

B. Initial state only

C. End states only

D. None of these

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4

For a given substance at a specified temperature, activity is __________ to fugacity.

A. Directly proportional

B. Inversely proportional

C. Equal

D. None of these

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4

The expression, nCv(T2 - T1), is for the __________ of an ideal gas.

A. Work done under adiabatic condition

B. Co-efficient of thermal expansion

C. Compressibility

D. None of these

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4

Pick out the wrong statement.

A. Enthalpies of all elements in their standard states are assumed to be zero

B. Combustion reactions are never endothermic in nature

C. Heat of reaction at constant volume is equal to the change in internal energy

D. Clausius-Clapeyron equation is not applicable to melting process

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4

The enthalpy change when ammonia gas is dissolved in water is called the heat of

A. Solution

B. Formation

C. Dilution

D. Combustion

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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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4

In a turbine, the fluid expands almost

A. Isothermally

B. Isobarically

C. Adiabatically

D. None of these

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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

1m3 of an ideal gas at 500 K and 1000 kPa expands reversibly to 5 times its initial volume in an insulated container. If the specific heat capacity (at constant pressure) of the gas is 21 J/mole . K, the final temperature will be

A. 35 K

B. 174 K

C. 274 K

D. 154 K

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4

Compressibility factor (i.e., the ratio of actual volume of gas to the volume predicted by ideal gas law) for all gases are

A. Always greater than one

B. Same at the same reduced temperature

C. Same at the same reduced pressure

D. Both (B) & (C)

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4

The change in Gibbs free energy for vaporisation of a pure substance is

A. Positive

B. Negative

C. Zero

D. May be positive or negative

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4

Cp - Cv = R is valid for __________ gases.

A. Ideal

B. Very high pressure

C. Very low temperature

D. All of the above

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4

At __________ point, all the three phases (i.e. solid, liquid and gas) co-exist.

A. Eutectic

B. Triple

C. Plait

D. Critical

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4

The main feature of Carnot refrigeration cycle is that, it

A. Does not need the addition of external work for its functioning

B. Transfers heat from high temperature to low temperature

C. Accomplishes the reverse effect of the heat engine

D. None of these

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4

The molar excess Gibbs free energy, gE, for a binary liquid mixture at T and P is given by, (gE/RT) = A . x1. x2, where A is a constant. The corresponding equation for ln y1, where y1 is the activity co-efficient of component 1, is

A. A . x22

B. Ax1

C. Ax2

D. Ax12

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4

Solubility of a substance which dissolves with an increase in volume and liberation of heat will be favoured by the

A. Low pressure and high temperature

B. Low pressure and low temperature

C. High pressure and low temperature

D. High pressure and high temperature