particle model of matter Flashcards
what does the particle model help show
explains how the particles at each stage behave
what are the forces of attraction in liquids
weak
why are solids fixed
they have strong forces of attraction
what happens when a gas is heated
pressure increases/container expands
what happens at each stage from gas to liquid to solid
strength of bonds / density increase
what is density measured in
g per cm3
density practical
find mass of object using mass balance
if it is regular find volume by finding lwh
if it is irregular use eureka can filled with water up to outlet with an empty measuring cylinder aligned underneath the outlet
the volume of the object will flow into the measuring cylinder
insert values into the equation
what can we do to reduce the uncertainty of density experiments
take multiple measurements and calculate a mean
When measuring the density of liquids, use a larger volume of liquid
on a graph of melting and boiling point over time why is there no temp increase at the certain melting and boiling points
the energy is being applied to the objects potential stores(forces holding particles together)
why is the temp constant when cooling
when changing state new bonds are being formed which releases energy which is what counteracts cooling keeping temp constant
what is the latent heat
the amount of energy needed to change state of substance while temp stays constant
what is the spec latent heat
energy required to change 1 kg of a substance from 1 state to another without changing temp
for cooling what is the spec latent heat
energy released by change in state
what are the 2 types of slh
vapourisation-energy change when substance changes from liquid to gas(evaporates or condenses)
fusion-energy change when substance changes between solid and liquid(melts or freezes)
slh of fusion and vapourisation when cooling would be
the amount of energy released instead of required
what is the equation of spec latent heat
e=ml
energy released /required(j)=mass(kg)x spec latent heat(j/kg)
how is pressure formed in a container
by the force gas particles exert on the walls of a container whenever they collide with it
what is the total pressure
no of collisions
energy of collisions
what factors affect gas pressure
temperature(inc
concentration(inc
volume(inc as it decreases
How volume affects pressure in a gas
Decreasing the volume of the container, whilst keeping the number of gas particles the same, will increase the concentration.
In this smaller volume, collisions between particles of gas and the walls of the container will be more frequent.
A greater number of collisions per unit area of wall means the pressure increases.
How temperature and concentration affect a flexible container
Some containers, such as balloons, are flexible.
An increase in force on the walls of the container would just cause the container to expand.
Therefore, changing temperature or concentration will change the volume of the container, rather than the pressure of the gases inside.
pressure x volume in 2 containers=
constant volume at constant temp
pressure and volume are
inversely related
