Dry ice is
Moisture free ice
Solid helium
Solid carbon dioxide
None of these
Correct Answer :
C. Solid carbon dioxide
Related Questions
(∂T/∂P)H is the mathematical expression for
Specific heat at constant pressure (Cp)
Specific heat at constant volume (Cv)
Joule-Thompson co-efficient
None of these
For a constant pressure reversible process, the enthalpy change (ΔH) of the system is
Cv.dT
Cp.dT
∫ Cp.dT
∫ Cv.dT
In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13°C and 37°C respectively, the Carnot COP will be
5.2
6.2
0.168
Data insufficient, can't be found out
Which of the following has the least thermal efficiency?
Steam engine
Carnot engine
Diesel engine
Otto engine
A cyclic engine exchanges heat with two reservoirs maintained at 100 and 300°C respectively. The maximum work (in J) that can be obtained from 1000 J of heat extracted from the hot reservoir is
349
651
667
1000
The adiabatic throttling process of a perfect gas is one of constant enthalpy
In which there is a temperature drop
Which is exemplified by a non-steady flow expansion
Which can be performed in a pipe with a constriction
In which there is an increase in temperature
The fugacity of a gas in a mixture is equal to the product of its mole fraction and its fugacity in the pure state at the total pressure of the mixture. This is
The statement as per Gibbs-Helmholtz
Called Lewis-Randall rule
Henry's law
None of these
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
35 K
174 K
274 K
154 K
What is the ratio of adiabatic compressibility to isothermal compressibility?
1
< 1
> 1
>> 1
Which one is true for a throttling process?
A gas may have more than one inversion temperatures
The inversion temperature is different for different gases
The inversion temperature is same for all gases
The inversion temperature is the temperature at which Joule-Thomson co-efficient is infinity
With increase in temperature, the internal energy of a substance
Increases
Decreases
Remains unchanged
May increase or decrease; depends on the substance
Mollier diagram is a plot of
Temperature vs. enthalpy
Temperature vs. enthalpy
Entropy vs. enthalpy
Temperature vs. internal energy
The ratio of equilibrium constants (Kp2/Kp1) at two different temperatures is given by
(R/ΔH) (1/T1 - 1/T2)
(ΔH/R) (1/T1 - 1/T2)
(ΔH/R) (1/T2 - 1/T1)
(1/R) (1/T1 - 1/T2)
Those solutions in which there is no volume change upon mixing the components in the liquid state and which, when diluted do not undergo any heat change (i.e. heat of dilution is zero), are called __________ solutions.
Ideal
Real
Isotonic
None of these
To obtain integrated form of Clausius-Clapeyron equation, ln (P2/P1) = (ΔHV/R) (1/T1 - 1/T2) from the exact Clapeyron equation, it is assumed that the
Volume of the liquid phase is negligible compared to that of vapour phase
Vapour phase behaves as an ideal gas
Heat of vaporisation is independent of temperature
All (A), (B) & (C)
If the pressure on 100 c.c. of air is halved, then its volume (at the same temperature) would be __________ c.c.
100
50
205
200
At absolute zero temperature, the __________ of the gas is zero.
Pressure
Volume
Mass
None of these
Entropy, which is a measure of the disorder of a system, is:
Independent of pressure
Independent of temperature
Zero at absolute zero temperature for a perfect crystalline substance
All (A), (B) & (C)
Internal energy change of a system over one complete cycle in a cyclic process is
Zero
+ve
-ve
Dependent on the path
Henry's law is closely obeyed by a gas, when its __________ is extremely high.
Pressure
Solubility
Temperature
None of these
Pick out the wrong statement.
A closed system does not permit exchange of mass with its surroundings but may permit exchange of energy.
An open system permits exchange of both mass and energy with its surroundings
The term microstate is used to characterise an individual, whereas macro-state is used to designate a group of micro-states with common characteristics
None of the above
When pressure is applied on the system, ice ↔ water, then
Equilibrium cannot be established
More ice will be formed
More water will be formed
Evaporation of water will take place
In the equation, PVn = constant, if the value of n = 1, then it represents a reversible __________ process.
Isothermal
Isobaric
Polytropic
Adiabatic
One ton of refrigeration capacity is equivalent to the heat removal rate of
50 kcal/hr
200 BTU/hr
200 BTU/minute
200 BTU/day
Grams of butane (C4H10) formed by the liquefaction of 448 litres of the gas (measured at (STP) would be
580
640
1160
Data insufficient; can't be computed
Pick out the wrong statement
Phase rule variables are intensive properties
Heat and work are both state function
The work done by expansion of a gas in vacuum is zero
CP and CV are state function
The number of degrees of freedom at the triple point of water is
0
1
2
3
No work is done by the system, when a reaction occurs at constant
Volume
Temperature
Pressure
None of these
Change of heat content when one mole of compound is burnt in oxygen at constant pressure is called the
Calorific value
Heat of reaction
Heat of combustion
Heat of formation
Third law of thermodynamics is concerned with the
Value of absolute entropy
Energy transfer
Direction of energy transfer
None of these