When an ideal gas is compressed adiabatically and reversibly, the final temperature is:

1. higher than the initial temperature

2. lower than the initial temperature

3. the same as the initial temperature

4. dependent on the rate of compression

1 liter-atmosphere is equal to:

1. 101.3 J                           

2. 24.20 cal

3. 101.3 x 10⁷ erg               

4. All of the above

An ideal gas expands at a constant external pressure of 2.0 atmosphere by 20 litre and absorbs 10kJ of heat from surrounding. What is the change in internal energy of the system:-

(1) 4052 J

(2) 5948 J

(3) 14052 J

(4) 9940 J

36 ml of pure water takes 100 sec to evaporate from a vessel and heater connected to an electric source which delivers 806 watt. The $∆{\mathrm{H}}_{\mathrm{vaporisation}}$ of H₂O is:-

(1) 40.3 kJ/mol

(2) 43.2 kJ/mol

(3) 4.03 kJ/mol

(4) None of these

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. Determine the change in internal energy $∆$U of the gas: