topic 3 - particle model of matter: changes of state and the particle model Flashcards
What is the equation which links density, mass and volume?
density = mass/volume
What is the symbol for density?
ρ
What is the symbol for mass?
m
What is the symbol for volume?
V
What are the units for density?
kg/m^3
What are the units for mass?
kilograms (kg)
What are the units for volume?
m^3
How are particles arranged in a material with high density?
Close together.
When you compress a material, what happens to its density?
It increases.
What are the three states of matter?
Solid, liquid and gas.
Which state of matter generally has the highest density?
Solids.
How do particles move in a solid?
They vibrate in fixed positions.
Do particles have a lot of energy in solids?
No (so they can only vibrate in fixed positions).
How do the forces of attraction in solids and liquids compare?
Solids have stronger forces of attraction than liquids.
How are particles arranged in a liquid?
Close together, but can move past each other, and form irregular arrangements.
How do particles move in a liquid?
In random directions at low speeds.
How does the energy of particles in solids and liquids compare?
Particles in liquids have more energy than in solids.
What are forces of attraction in gases like?
Very weak - almost none.
Do gas particles have more or less energy than liquids and solids?
More energy.
How do particles move in gases?
In random directions at high speeds.
What is the density of a gas like?
Low.
When a substance changes state, what happens to its mass?
It is conserved (stays the same).
Is a change of state a physical or chemical change and why?
Physical change - the material recovers its original properties if the change of state is reversed.
What is the change of state from solid into liquid called?
Melting.
