Topic 3 – Particle Model of Matter Fundamentals Flashcards
what does the density tell you
the mass for a given volume
whats the equation for density?
density = mass / volume
whats the unit of density?
kg/m ^3
whys polystyrene solid but has low density?
v open structure and is full of air spaces , it has a small mass for its volume
how to find density of a regular object?
1/ determine the mass using a balance
2/ measure length of each side using a ruler to find volume
3/ put into equation
how to find density of an irregular object
1/ find mass using balance
2/ fill eureka can w water and put measuring cylinder by spout. place object into water and see how much water was displaced.
3/measure waters volume
what is potential energy
intermolecular forces and chemical bonds
what is the internal energy
energy stored in a system by the particles
its the total kinetic energy and potential energy of all particles that make up a system
what happens when you heat a solid (in terms of internal energy)
internal energy increases
solid directly to a gas is called what?
sublimation
what is evaporation
when a liquid turns to a gas but only on the surface of the liquid. only particles on the surface have enough energy to turn into gas
what is the specific heat capacity
the amount of energy required to raise the temp of 1kg of a substance by 1 degree C
In a heating and cooling graph, when is change in state happening?
when the temp stops rising and line becomes horizontal
what happens to particles when theyre changing state?
energy being put in is weakening/ breaking the forces of attraction between them, allowing a change of state
what is increasing and staying the same during a change of state?
internal energy store is increasing but temperature does NOT increase
what is specific latent heat
the amount of energy required to change the state of 1kg of the substance with NO change in temperature
what is the specific latent heat of FUSION?
the energy required to change 1kg of a substance from a solid to liquid with no change in temp
what is the specific latent heat of VAPORISATION?
The energy required to change 1kg of a substance from a liquid to a vapour with no change in temperature
whats the pressure of a gas due to?
particles colliding with the walls of the container that the gas is held in. The particle collisions cause a force which act at right angles to the walls of the container. This force acting over areas of the container causes pressure.
how to increase the pressure of a gas?
increase the number of collisions per second OR the energy of each collision
(eg increase temp of gas)
whys lower temp of gas a lower pressure?
At low temperatures, particles have lower kinetic energy so there are fewer collisions per second. These are lower energy collisions
What happens if you take the same gas and increase of the volume of the container (w/ constant pressure)
pressure is reduced because there’s increased spacing between particles, they now travel much further before colliding with walls of the container, this reduces n.o of collisions per second between particles and the walls of the container
the pressure of gas is ______ to the volume meaning….
inversely proportional
if volume increases, pressure decreases
whats the equation for the constant?
pressure (Pa) x Volume = constant
because pressure multiplied by the volume is a constant, if we double the pressure we _____ the volume
halve
if you compress the gas by applying a force on the piston, its an example of what?
work done on the gas
what is work defined as
the transfer of energy by a force
what does is mean to have transferred energy by force?
the internal energy of the gas increases. And due to kinetic energy increasing, temp increases.
why can bicycle pumps get warm (sans)
because work is being done, increasing the internal energy
