The Particle Model Of Matter Flashcards
(24 cards)
Describe a solid.
• regular fixed arrangement
• low energy
• vibrate around a fixed position
Describe a liquid.
• close together irregular arrangement
• More energy - move in random directions with a range of speeds
• can move past each other
Describe a gas.
• High energy
• Far apart - almost no forces of attraction between particles
• Free to move - travel in random directions at a range of speeds higher than in a liquid
What is the equation for density?
Density = mass / volume
(Kg/m^3) (kg) (m^3)
ρ = m/V
What is the equation for extra pressure? (for pressure in fluids)
Extra pressure = height of liquid x density of liquid x gravitational field strength
P = hρg
What is temperature?
A measure of the average kinetic energy of the particles in a system.
What three factors can affect the pressure of a gas? And why?
• temperature
• volume of the container
• number of particles
These factors affect the frequency of collisions with the walls of the container.
As well as increasing the frequency of collisions between particles and the walls of the container, what does temperature also affect?
The force exerted by each collision.
What is the equation for Pressure?
Pressure = force/area
P = F/A
What happens when a gas is compressed? (E.g. in a gas syringe)
When a gas is compressed, work is done on the gas (W=Fd) and so energy is transferred to the thermal store of the gas and the temperature increases.
Why does atmospheric pressure decrease with altitude?
The number of particles above a surface decreases with altitude so the frequency of collisions with surfaces decreases.
Why does upthrust occur?
Upthrust occurs in liquids/fluids because the pressure is greater at the base of the object than at the top (so there is a resultant force exerted upwards)
What needs to happen for an object to float?
Objects float when: upthrust = weight
How can you tell if an object will sink?
If the density of an object is greater than that of the fluid it’s in the upthrust will always be smaller than the weight and so it will sink.
What is internal energy?
Internal energy is the sum of the total kinetic energy and the total potential energy of the particles in a system.
What does specific heat capacity measure?
Specific heat capacity is how much energy 1kg of a material requires to raise its temperature by 1°C.
What is the equation for specific heat capacity?
Energy=mass x specific heat capacity x change in temperature
E = mcΔΦ
What does specific latent heat measure?
Specific latent heat is the energy required by 1kg of a material to change state (without changing temperature).
Which specific latent heats should be used when? (Fusion/vaporisation)
Fusion - liquid to solid/solid to liquid
Vaporisation - liquid to gas/gas to liquid
Equation for specific latent heat
Energy = mass x specific latent heat
E = mL
What unit is specific heat capacity measured in?
J/kg°C
What unit is specific latent heat measured in?
J/kg
How would you find the volume of an irregular solid?
For an irregular solid, you can find its volume by submerging it in a Eureka can filled with water.
The water displaced by the object will be transferred to the measuring cylinder and you can record the volume of water to find the volume of the object.
How would you find the density of an irregular solid?
For an irregular solid, you can find its volume by measuring its mass and then submerging it in a Eureka can filled with water.
The water displaced by the object will be transferred to the measuring cylinder and you can record the volume of water to find the volume of the object.
Plug the mass and volume into the density equation to find the density.
