The number of molecules present in 1 mL of gas or vapor at STP is:

1. called Loschmidt's number

2. equal to 2.617 x 10¹⁹ per mL

3. both (1) and (2)

4. none of the above

 Air at sea level is dense. This is a practical application of:

1. Boyle's law                         

2. Charles' law

3. Avogadro's law                   

4. Dalton's law

In van der Waals' equation of state of the gas, the constant 'b' is a measure of:

1. Intermolecular collisions per unit volume

2. Intermolecular attraction

3. Volume occupied by molecules

4. Intermolecular repulsions

For 1 mole of gas, the average kinetic energy is given as E. The u_rms of gas is :

1. [2E/M]^1/2

2. [3E/M]^1/2

3. [2E/3M]^1/2

4. [3E/2M]^1/2

600 cc of a gas at a pressure of 750 mm is compressed to 500 cc. Taking the temperature to remain constant, the increase in pressure is:                                         

1. 150 mm                       

2. 250 mm

3. 350 mm                      

4. 450 mm

An ideal gas expands according to PV=constant. On expansion, the temperature of the gas:

1. Will rise.

2. Will drop.

3. Will remain constant.

4. Cannot be determined because the external pressure is not known.

The correct statement for an ideal gas equation is -

1. n is the number of molecules of a gas.

2. V denotes the volume of 1 mole of the gas.

3. n moles of a gas has a volume V.

4. p is the pressure of the gas when only one mole of the gas is present.

The gas among the following that can be most steadily liquefied is -

1. NH₃                           

2. Cl₂

3. SO₂                           

4. CO₂

Internal energy and pressure of a gas per unit volume are related as                       

1. p= $\frac{2}{3}$E                         

2. p = $\frac{3}{2}$E

3. p=$\frac{1}{2}$E                         

4. p = 2E

If a gas expands at constant temperature, it indicates that                                     

1. kinetic energy of molecules decreases

2. pressure of the gas increases

3. kinetic energy of molecules remains the same

4. number of the molecules of gas increases