Which of the following situations would cause the greatest increase in the motion of molecules in a system? a. the system absorbs 100 j of heat and has 100 j of work done to it. b. the system absorbs 100 j of heat and does 100 j of work. c. the system releases 100 j of heat and does 100 j of work. d. the system releases 100 j of heat and has 100 j of work done to it.

A. The system absorbs 100 J of heat and has 100 J of work done to it.

Explanation: According to first law of thermodynamics:

=Change in internal energy

q = heat absorbed or released

w = work done or by the system

w = work done by the system=

{ Work is done by the system as the final volume is greater than initial volume and is negative and work done on the system is positive.}

1. The system absorbs 100 J of heat and has 100 J of work done to it.

2. The system absorbs 100 J of heat and does 100 J of work.

3. The system releases 100 J of heat and does 100 J of work.

4. The system releases 100 J of heat and has 100 J of work done to it.

As internal energy is the function of temperature, a positive increase in internal energy means the temperature has increased and thus the motion of particles will be greatest.