19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
E is always positive, when
According to the first law of thermodynamics, U q w . In special cases the statement can be expressed in different ways. Which of the following is not a correct expression?
U q w , is mathematical expression for
In a reaction, all reactant and products are liquid, then (a) H E (b) H E (c) H E
A sample of liquid in a thermally insulated container (a calorimeter) is stirred by a motor. Taking liquid as a system for this process choose the appropriate option:
Calculate the work done when 1 mol of an ideal gas is compressed reversibly from 1 bar to 4 bar at a constant temperature of 300 K
Gaseous system is placed with pressure P₁, volume V₁ and temperature T1, it has undergone thermodynamic changes where temperature is remaining constant, it is
Based on the first law of thermodynamics, which one of the following is correct?
In ….. process, work is done at the expense of internal energy.
16g of oxygen gas expands isothermally and reversibly at 300 K from 10 dm3 to 100 dm3. The work done is (in J)
For the reaction, 2H O g 2H g O g → ∆H = 571.6 KJ fH of water is :
Assertion: In isothermal process, whole of heat energy supplied to the system is converted into internal energy. Reason: According to the first law of thermodynamics U = q - w
Calculate the mass of urea (NH₂CONH₂) required in making 0.25 molal aqueous solution using 2.5 L water. (Haryana PMT 2010)
Assertion: 1.575g H₂C₂O₄.2H₂O in 250 mL solution makes it 0.1 N. Reason : H₂C₂O₄.2H₂O is a dihydrate organic acid.
25.3 g of sodium carbonate, Na₂CO₃ is dissolved in enough water to make 250 mL of solution. If sodium carbonate dissociates completely, molar concentration of sodium ion and carbonate ions respectively are (Molar mass…
A solution contains non-volatile solute of molecular mass M2. Which of the following can be used to calculate the molecular mass of solute in terms of osmotic pressure? (Punjab PMET 2007) (a) m M VRT (b) m RT M V (c) …
At o 25 C, the total pressure of an ideal solution obtained by mixing 3 moles of ‘A’ and 2 moles of ‘B’, is 184 torr. What is the vapour pressure (in torr) of pure ‘B’ at the same temperature? (Vapour pressure of pure…
60 mL of N/5 H₂SO₄, 10 mL of N/2 HNO₃ and 30 mL of N/10 HCl are mixed together. The strength of the resulting mixture is (UP CPMT 2009)
An aqueous solution is 1.0 molal in KI. Which change will cause the vapour pressure of the solution to increase? (AIPMT 2010)
If sodium sulphate is considered to be completely dissociated into cations and anions in aqueous solution, the change in freezing point of water ( Tf), when 0.01 mole of sodium sulphate is dissolved in 1 kg of water, …
0.01 M solution each of urea, common salt and Na₂SO₄ are taken, the ratio of depression of freezing point is
If is degree of dissociation of Na₂SO₄, the van’t Hoff’s factor, i, used for calculating the molar mass is
Which of the following pair of solutions are expected to be isotonic at the same temperature?
Four solutions of K₂SO₄ with the following concentration 0.1 m, 0.01 m, 0.001 m and 0.0001 m SOLUTIONS are available. The maximum value of van’t Hoff factor, i, corresponds to
Van’t Hoff factor of Ca (NO₃)₂ is