Background
Phase change of matter requires either the input or extraction of energy from it, the energy required is referred to enthalpy of fusion or enthalpy of vaporization etc. depending on the change. Some phase changes are easy to bring about, i.e. the energy change is very small and therefore the process is spontaneous, while others are non-spontanesous. Phase change in matter is also frequently accompanied by changes in properties, such as pressure of gas, which at times may produce dramatic results.
Resources:
The following links are to PowerPoint slides on my homepage:
Discrepant Event
Liquid nitrogen is poured into a plastic bottle containing some water. It is then inverted over a ring clamp. Watch the video to find out what happens next.
And the questions are:
- Why did the liquid nitrogen cause the plastic bottle to break up so violently?
- What’s the explanation for the loud bang?
Concepts involved:
- heat transfer, boiling/evaporation, temperature/heat, pressure, number of gas particles (Addtional concept: phase equilibria)
- gas law, moles of gas particles, expansion.
