MEDIUM
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Does the drawing represent a solid or a liquid? Give two reasons for your answer.

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Important Questions on Develop a model that predicts and describes changes in particle motion, temperature, and state of a pure substance when thermal energy is added or removed.

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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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.
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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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)
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:
MEDIUM

Which of the following statements are true?

I. On heating the kinetic energy of particles in solids does not change because they have a fixed position.

II. Sublimation is the change of gaseous state directly to solid state without going through liquid state and vice versa.

III. The movement of particles from an area of higher concentration to lower concentration is called diffusion.

IV. The rate of evaporation is not affected by increasing the temperature.

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

The three processes in a thermodynamic cycle shown in the figure are : Process 12 is isothermal; Process 23 is isochoric (volume remains constant); Process 13 is adiabatic.

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The total work done by the ideal gas in this cycle is,10 J. The internal energy decreases by, 20 J in the isochoric process. The work done by the gas in the adiabatic process is, -20 J. The heat added to the system in the isothermal process is

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 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)