Answer:
basically they have too much mass in them
Explanation:
They are held tightly together by strong forces of attraction. They are held in fixed positions but they do vibrate. Because the particles don't move, solids have a definite shape and volume, and can't flow. Because the particles are already packed closely together, solids can't easily be compressed.
Answer:
Δu=1300kJ/kg
Explanation:
Energy at the initial state

Is saturated vapor at initial pressure we have

Process 2-3 is a constant volume process

The overall in internal energy
Δu=u₁-u₃
We replace the values in equation
Δu=u₁-u₃

Δu=1300kJ/kg
Answer: 20
Explanation: Mass number is the number of neutrons plus the number of protons. 8 + 12 gives 20.