Section 5 - Changes of state Flashcards
What is different in solids, liquids and gases?
Their arrangements and energy of the particles are different.
Describe the lattice of a solid.
There are strong forces of attraction holding the particles close together in a fixed regular arrangement. The particles don’t have much energy so they can only vibrate about their fixed positions.
Describe the lattice of a liquid.
Weaker forces of attraction
Particles close together
Particles move past each other
Irregular arrangements
More energy than solids
Move randomly at low speeds
Describe the lattice of gases.
Almost no force of attraction
Particle have more energy than liquids and solids
Free to move
Travel random directions
High speeds
What happens when you heat up a liquid?
Heat energy makes particles move faster. Eventually, when enough particles have enough energy to overcome their attraction to each other, bubbles of gas form in the liquid.
Boiling
What is evaporation?
It is when particles escape from a liquid and become gas particles.
What temperature do particles evaporate at?
Temperatures that are much lower than the liquids boiling point.
Which particles are able to evaporate?
Particles that are near the surface
Particles that are traveling in the right direction to escape the liquid.
Particles that are traveling fast enough
(Have enough kinetic energy) to overcome the attractive forces of the other particles in the liquid.
What happens when evaporation happens?
When the fastest particles evaporate, the average temperature of the remaining liquid falls. The liquid cools.
As water from sweat on skin evaporates if cools you down.
