Energy of Matter Flashcards
What sort of change is change of state?
Physical
Describe the arrangement of particles in gases.
Particles spread out, almost no forces of attraction, large distance between them
Describe the movement of particles in gases.
Move in random directions at high speeds.
What are the properties of gases?
- Low density
- No fixed volume or shape
- Can be compressed
- Can flow
- Spread out to fill all available space
Describe the arrangement of particles in liquids.
- Particles in contact with each other
- Forces of attraction between
- Particles weaker than in solids
Describe the movement of particles in liquids.
Particles move randomly.
Describe the properties of liquids.
- Usually lower density than solids.
- Fixed volume
- Shape not fixed - can flow
Describe the arrangements of particles in solids.
Particles next to each other (tightly packed) - strong forces of attraction
Describe the movement of particles in solids.
Particles vibrate in fixed positions.
Describe the properties of solids.
- High density
- Fixed volume
- Fixed shape (unless deformed by external source)
What affect does temperature increase have on particles?
Kinetic energy store increases -> particles vibrate faster
What can happen if the kinetic energy store of a substance increases or decreases too much?
Change of state
What is internal energy?
The sum of the total kinetic energy particles have due to their motion, and the total potential energy of particles due to their positions relative to each other.
How can you increase internal energy?
Heat the substance
What is latent heat?
The energy transferred when a substance changes state.
What is specific latent heat?
The energy required to change 1kg of a substance without a change in temperature.
What is specific latent heat of fusion?
The energy required to melt 1kg of a substance without a change in temperature.
What is specific latent heat of vaporisation?
The energy required to evaporate 1kg of a substance without a change in temperature.
What does a flat line on a heating-time graph show?
Change of state
What happens when a gas is heated?
Particles gain kinetic energy, move faster -> temperature of gas increases
How is pressure exerted by a gas?
The force of the gas particles hitting a surface
What does the pressure of a gas produce on a container?
A net force at a normal (right angle) to the container’s walls
What happens when the temperature of a gas in a sealed container increases?
- Particles move faster so hit surfaces with more force.
- Number of impacts per second (MFSC), so more force exerted overall.
- Pressure increases
What can happen when a gas is compressed quickly?
Rapid temperature increase
Why does the compression of a gas cause the temperature to rise?
- Force applied to gas -> work is done (W = Fd)
- Energy gained by gas is not transferred quickly enough to surroundings
What happens when the volume of a fixed mass of gas (at constant temperature) is decreased?
Pressure increases
Why does a decrease in the volume of a gas lead to a pressure increase?
- Distance particles travel between impact with wall decreases
- Number of impacts per second increases (MFSC)
- So total force of impacts increases
Why does an increase in the volume of a gas lead to a pressure decreas?
- Distance between particles and impact with wall increases
- Number of impacts per second decreases
- So total force of impacts decreases
