C1.1.3-limitations To The particle Model Flashcards
What are the smallest particles that make up a substance called?
Atoms
Helium atoms are the smallest of all atoms, at just 62 pm in diameter.
What is the diameter of a helium atom in meters?
62 x 10^-12 m
This is approximately a billion times smaller than a tennis ball.
How far apart are two helium atoms in the gas state compared to their diameter?
55 times larger
This makes it difficult to draw gas particles to scale.
What is the mean distance between two helium atoms in the gas state?
3.4 x 10^-9 m
Calculate the ratio of distance to diameter for helium atoms in the gas state. What is the ratio?
55
This is calculated by dividing the mean distance by the diameter of the atom.
What are the forces between particles primarily described as?
Electrostatic forces of attraction
These forces are between positive and negative charges.
How do the forces between particles change with distance?
They become weaker the further apart the particles are.
In which state of matter are the attractive forces between particles strongest?
Solids
What are three limitations of the particle model?
- It does not account for the forces between particles
- It does not consider the size of particles
- It does not include the space between particles
What happens to the volume of a substance when it melts?
It usually increases a little.
What occurs to the volume when a liquid becomes a gas?
It increases a great deal.
What type of collisions do particles undergo in the particle model?
Inelastic collisions
This means energy is transferred to the surroundings during collisions.
True or False: Particles change size during state changes.
False
Particles do not change size during state changes or temperature changes.
What indicates that forces of attraction are weaker in liquids compared to solids?
The volume increases when a solid melts.
Why does liquid water expand when it freezes?
Due to the unique arrangement of water particles in ice.
What is the diameter of a caesium atom in meters?
6.0 x 10^-10 m
What is the mean distance between caesium atoms in the gas state?
5.1 x 10^-9 m
Calculate the ratio of distance to diameter for caesium atoms.
To be calculated based on given data.
