EASY
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Among the following substances the lowest vapour pressure is exerted by

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Important Questions on States of Matter

MEDIUM
At 35 oC, the vapour pressure of CS2, is 512 mmHg and that of acetone is 144 mmHg. A solution of CS2 in acetone has a total vapour pressure of 600 mmHg. The false statement amongst the following is:
MEDIUM

The combination of plots which does not represent isothermal expansion of an ideal gas is

(A) Question Image

(B) Question Image

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HARD
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The above P-V diagram represents the thermodynamic cycle of an engine, operating with an ideal mono-atomic gas. The amount of heat, extracted from the source in a single cycle, is:
EASY
The work done during combustion of 9×10-2 kg of ethane, C2H6(g) at 300 K is (Given R=8.314 JK1mol1 , atomic mass C=12,H=1 )
MEDIUM
1 kg of water, at 20 °C is heated in an electric kettle whose heating element has a mean (temperature averaged) resistance of 20Ω. The rms voltage in the mains is 200 V. Ignoring heat loss from the kettle, time taken for water to evaporate fully is close to
[ Specific heat of water =4200 J kg-1 °C-1 Latent heat of water =2260 kJ kg-1 ]
MEDIUM
A system consisting of 1 mol of an ideal gas undergoes a reversible process, ABCA (schematically indicated in the figure below). If the temperature at the starting point A is 300 K and the work done in the process BC is 1 L atm, the heat exchanged in the entire process in L atm is

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HARD
A reversible cyclic process for an ideal gas is shown below. Here, P, V, and T are pressure, volume and temperature, respectively. The thermodynamic parameters q, w, H and U are heat, work, enthalpy and internal energy, respectively.

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The correct option(s) is (are)
EASY
A gas undergoes change from state A to state B. In this process, the heat absorbed and work done by the gas is 5 J and 8 J, respectively. Now gas is brought back to A by another process during which 3 J of heat is evolved. In this reverse process of B to A.
EASY
Latent heat of vaporisation of water is 22.6×105 J kg-1. The amount of heat needed to convert 100 kg of water into vapour at 100 °C is
MEDIUM
The qualitative sketches I, II and III given below show the variation of surface tension with molar concentration of three different aqueous solutions of KCl, CH3OH  and CH3CH211OSO3- Na+ at room temperature. The correct assignment of the sketches is -

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EASY
Calculate the work done during compression of 2 mol of an ideal gas from a volume of 1m3 to 10 dm3 at 300 K against a pressure of 100 kPa.
EASY
A piece of ice falls from a height h so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of h is:
(Latent heat of ice is 3.4×105J kg-1 and g=10N kg-1)
MEDIUM
X g of ice at 0oC is added to 340g of water at 20oC . The final temperature of the resultant mixture is 5oC . The value of X (in g) is closest to

[Heat of fusion of ice =333 J/g ; Specific heat of water =4.184 J/g.K ]
MEDIUM
A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of 3 7 . 0 C. As it does so, it absorbs 208 J of heat. The values of q and w for the process will be 
(R = 8.314 J/mol K) (ln7.5 = 2.01)
EASY
An ideal gas undergoes isothermal expansion at constant pressure. During the process:
MEDIUM
A gas is allowed to expand in a well-insulated container against a constant external pressure of 2.5 atm from an initial volume of 2.50 L to a final volume of 4.50 L. The change in internal energy ΔU of the gas in joules will be
MEDIUM
For the isothermal reversible expansion of an ideal gas
HARD
An ideal gas undergoes isothermal compression from 5 m3 to 1 m3 against a constant external pressure of 4 N m-2. The heat released in this process is 24 J mol-1K-1 and is used to increase the pressure of 1 mole of Al. The temperature of Al increases by:
EASY
A closed bottle containing water at 30oC is open on the surface of the moon. Then-
HARD
A graph of vapour pressure and temperature for three different liquids X,Y and Z is shown below:
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The following inferences are made:
AX has higher intermolecular interactions compared to Y.
BX has lower intermolecular interactions compared to Y.
CZ has lower intermolecular interactions compared to Y.
The correct inferences is/are: