Topic 3- Particle Model Of Matter Flashcards
What is the definition and unit of density?
Mass per unit volume of a material (m/v)
Describe particle arrangement in a solid
Tightly packed in regular arrangement- only vibrate on spot
Describe particle arrangement in liquid
Close together, but irregular arrangement. They can flow over each other
Describe the particle arrangement in a gas
Separated- no regular arrangement. Particles move freely
What is always conserved when a substance undergoes a state change?
Mass
How does change of state differ from chemical change?
Change of state- can return to previous properties if change is reversed
What is sublimation?
When a solid changes into a gas without passing through a liquid state
Explain process when bathroom mirror steams up
Hot water evaporates to form water vapour
Water vapour lands on cool mirror and condenses, returning to liquid state
What is the internal energy of a substance?
Energy stored by the particles
Sum of kinetic and potential energies that make up a system
How does heating affect energy of a substance
Transfers energy to substance
Increases energy of particles of substance
What 2 things can heating a substance do?
- Raise temp
2. Change its state
What 3 factors determine temperature change in a system?
- Mass of substance
- Type of material
- Energy inputted
Define specific heat capacity
Amount of energy needed to increase 1Kg of a substance by 1ºC
How do internal energy and temp of a substance change when a state change occurs?
Internal energy- increased or decreased
Temp- remain constant
Define specific latent heat
Amount of energy needed to change the state of 1Kg of a substance without a change in temperature
What is the specific latent heat of fusion?
Energy required to change 1Kg of a substance from solid to liquid without temperature change
What is specific latent heat of vaporisation?
Energy required to change 1Kg of a substance from liquid to gas without temperature change
Describe motion of molecules in gas
In a constant random motion
What factor affects average kinetic energy of gas molecules?
Higher temperature, higher average kinetic energy of molecules
If one gas is at low pressure, and one at high, what can be said about the rate of collisions in each gas?
More collisions per second in high pressure gas than low pressure
Explain how increasing volume of a gas decreases pressure
Molecules spread out- time between collisions is shorter.
Reduces rate of collisions
Rate of change of momentum decreases- force exerted on container decreases- lower pressure
What is the unit for pressure
Pa (pascal)
What increases when you do work on a gas?
Internal energy of gas
Can lead to ncrease of temperate
