Please enable JavaScript.
Coggle requires JavaScript to display documents.
P6: molecules and matter (changes of state (For a pure substance:
-its…
P6: molecules and matter
-
states of matter
-
Gas:
-particles move about randomly and are far apart
-low density
-can flow
-no fixed volume
-fills container(no shape)
liquid:
-particles move about at random and are in contact with each other
-can flow
-medium density
-fits container (no fixed shape)
-fixed volume
when a substance changes state its mass stays the same because the number of particles does not change
changes of state
For a pure substance:
-its melting point is the temp at which it melts (same temp it solidifies)
-its boiling point is the temp at which it boils (same temp it condenses)
-
Boiling occurs through out a liquid at its boiling point. Evaporation occurs from the surface of the liquid when its temp is below its boiling point
-
-
-
-
-
internal energy
-
the strength of forces of attraction between particles of substance explains why it is a solid, liquid or gas
When a substance is heated:
-its temp rises, kinetic energy of particles increases
-if it melts or boils, kinetic energy of particles decreases
The pressure of a gas on a surface is caused by the particles of the gas repeatedly hitting the surface
specific latent heat
-
Specific latent heat of fusion/ vaporization is the energy needed to melt/ boil 1kg of a substance without changing its temp
-
-
Gas pressure and temp
the pressure of gas is caused by random impacts of gas molecules on surfaces that are in contact with the gas
If temp of gas in sealed container increases then the pressure of gas increases because:
-the molecules move faster so hit the walls with more force
-the number of impacts per second increases so the total force of the impacts increases
-
gas pressure and volume
For a fixed mass of gas at a constant temp:
-its pressure increases if its volume increases
-reducing the volume of a gas increases the number of molecular impacts per second on surfaces
-
the temp of a gas can increase if it is compressed rapidly because work is done on it and energy isn't transferred quickly enough to its surroundings