1 - Kinetic Particle theory Flashcards
Solid state (fixed shape)
- Arrangement of particles
- Attractive forces between particles
- Kinetic energy particles
- Motion of particles
> Closely packed in an orderly manner
Held tgt by v strong forces of attraction
Enough KE to vibrate and rotate about their fixed positions
Cannot move about freely
Why does a solid have a fixed volume?
A solid cannot be compressed/ has a fixed volume since it’s particles are already very close to one another
Liquid state (fixed shape)
- Arrangement of particles
- Attractive forces between particles
- Kinetic energy particles
- Motion of particles
> Arranged in disorderly manner
Weaker forces of attraction than the particles of a solid
More KE than the particle of the same substance in solid state, and are not held in fixed positions
Move freely throughout the liquid
Why does liquid have a fixed volume?
The particles of a liquid are further away from one another than the particles of a solid
HOWEVER
The liquid particles are still packed quite close togerther
THUS
It cannot be compressed and has a fixed volume
Describe gaseous state (no fixed shape)
- Arrangement of particles
- Attractive forces between particles
- Kinetic energy particles
- Motion of particles
> Far apart from one another
Has weaker forces of attraction than particles of a liquid
A lot of KE and are not held in fixed positions
Can move about rapidly and freely
Why does gas not have a fixed shape?
- A lot more space between them compared to the particles of a liquid or solid
- Large space between particles allows the gas to be easily compressed when pressure is applied
- In other words, particles of gas can be forced to move closer tgt
SINCE
A gas can be compressed, it has no fixed volume
(Extra?)
Endothermic vs Exothermic
First one is heat in second one is heat out
Define the process melting
It’s the process by which a substance changes from a solid to a liquid
There are 3 stages to the process of melting, describe the first stage of melting (from solid to liquid)
- Heat energy absorbed by particles of solid
- HE converted to KE
- Particles start to vibrate FASTER about their fixed positions
There are 3 stages to the process of melting, describe the second stage of melting (from solid to liquid)
- When temp high enough, vibrations of particles become sufficient to OVERCOME forces of attraction between them
- Particles begin to break away from fixed positions
[Note: When HE^, KE^] [Overcoming forces of attraction is not considered KE, thus no ^ in HE]
There are 3 stages to the process of melting, describe the third stage of melting (from solid to liquid)
- Particles no longer in fixed positions
- Substance now liquid
- . Particles can move FREELY throughout liquid
Describe the first stage at which particles of a liquid is cooled until it freezes
- Energy is given out by particles of the liquid
2. Particles lose KE and begin to move more slowly
Describe the second stage at which particles of a liquid is cooled until it freezes (mixture of solid and liquid, no temp. change)
- When the temp. is low enough, particles no longer have enough energy to move freely
- Particles start to settle into fixed positions
Describe the third stage at which particles of a liquid is cooled until it freezes
- All particles have settled into fixed positions
- Substance now solid
- Particles can only vibrate about their fixed positions
Define the process of freezing
Process where substance changes from liquid to solid
What is freezing/ melting point
The temp. at which a liquid substance becomes solid and vice versa
Define the process of boiling and evapouration
The process at which liquid changes to gas AT boiling point(boiling)
For evaporation, liquid changes to gas at temp LOWER than boiling point
Describe the first stage at which particles of a liquid is heated until it boils
- HE absorbed by particles of liquid
- HE converted into KE
- partiles start to move faster as the temp. rises
Describe the second stage at which particles of a liquid is heated until it boils (No temp. change, reached plateau)
When temp. is high enough, particles have enough energy to overcome the forces of attraction holding them tgt
Describe the third stage at which particles of a liquid is heated until it boils
- Particles are now spread far apart
- Substance is now a gas
- Particles can move about in any direction
Observation as liquid boils
- Bubbles of gas formed when liquid changes to a gas
- Bubble rise to surface and escape into the air
Diff between boiling and evaporation
Boiling occurs:
- Only at boiling point
- Throughout liquid
- Rapidly
Evaporation occours:
> At temps. below boiling point
> only at surface of liquid
> Slowly
Define process of condensation
Process at which a gas changes to a liquid
What happens to the particles of a gas when the gas condenses? (kinda the opposite of boiling)
- HE given out by gas particles
- As temp. drops, particles lose energy and move more slowly
- Particles become slow enough for the gas to change to liquid
What is sublimation?
Changing of state from solid directly to gas without going through liquid state
Why do solids sublime/ why it occurs?
Occurs when particles at surface of solid have enough energy to break away from the solid and escape as a gas
Define diffusion
A process by which particles move freely to fill up any available space
What is a molecular mass?
Mass of the particles of the gas
Effect of temp on the rate of diffusion?
Temp. ^ , energy increases too
Thus particles diffuse faster which increases the rate of diffusion
How does Mr affect the rate of diffusion
Gases with lower molecular masses (Mr) diffuse faster than those with higher molecular masses
Why would a heterogenous mixture eventually become a homogenous mixture over time?
The [insert] particles would diffuse from a region of higher concentration to a region of lower concentration.