1.4.1 Changes in State: Energy Changes Flashcards
Changes of state are
physical changes that are reversible
Changes of state are physical changes that are reversible, these changes do not change
the chemical properties or chemical makeup of the substances involved
Vaporisation includes
evaporation and boiling
Evaporation involves
the change of liquid to gas, but unlike boiling, evaporation occurs only at the surface and takes place at temperatures below the boiling point
Boiling occurs at a specific temperature and takes place when
the vapour pressure reaches the external atmospheric pressure
State Changes diagram
The relationship between temperature and energy during state changes graph
Between 1 & 2
the particles are vibrating and gaining kinetic energy and the temperature rises
Between 2 & 3
all the energy goes into breaking bonds – there is no increase in kinetic energy or temperature
Between 3 & 4
the particles are moving around and gaining in kinetic energy
Between 4 & 5
the substance is boiling, so bonds are breaking and there is no increase in kinetic energy or temperature
From 5 & 6
the particles are moving around rapidly and increasing in kinetic energy
To break bonds, energy is always needed
to overcome the forces of attraction between the particles
