5.6. Internal Energy

Question 1

Internal energy

Answer 1

The sum of the K.E. of molecules due to its random motion & the P.E. of the molecules due to the intermolecular forces.

Question 2

Liquids: k.e. ≈ p.e

Answer 2

• Molecules far apart and in continuous motion = p.e.
• Intermolecular force present and keep shape = p.e.

Question 3

Gases: k.e. > p.e

Answer 3

• Molecules far apart and in continuous motion = p.e.
• Weak intermolecular forces so very little p.e.

Question 4

Solids: k.e. < p.e.

Answer 4

• Molecules can only vibrate ∴ k.e. very little
• Strong intermolecular forces p.e. high
  *