particle model of matter Flashcards
what is density defined as?
mass per unit volume of a material
unit of density
g/cm^3
kg/m^3
mass vs denisty vs weight
mass- amount of matter in a substance or object- kg
density- amount of matter in a fixed volume- kg.m^3
weight- force that acts on that object in prescence of a gravitational field- N
solid
- density
- arragement of particles
- movement of partcles
- energy of particles
- high
- regular arragement
- vibrate around fixed position
- low energy
liquid
- density
- arragement of particles
- movement of partcles
- energy of particles
- medium
- randomly arranged
- move around each other
- greater energy
gas
- density
- arragement of particles
- movement of partcles
- energy of particles
- low
- randomly arranged
- move quickly in all directions
- highest energy
what is conserved when changing state?
mass as no. molecules doesnt change
why is change of state reversible?
physical changes NOT chemical
describe all 5 change of state
solid -melting> liquid
liquid -evapourating> gas
gas -condensing> liquid
liquid -freezing> solid
solid -sublimimation> gas
what is internal energy?
energy which is stored by particles within a system
forms of internal energy in particles
- kinetic energy (vibration)
- potential (between the partciles)
how does heating effect partcles and the system?
- increases internal energy- specificallty kinetic energy
- ^ causes temp of system to increase
- OR produce change of state
what happens to the energy when changing state?
when reaching certain temp- internal energy transfers from kinetic energy to potential energy to overcome intermoleular forces of attraction
- kinetic energy stays- temp stays constant
what is the definition of specific heat capacity?
and unit?
the amount of energy required to raise the temperature of 1kg of substance by 1^C
J/kg^C
low specific heat capacity vs high
in terms of energy required
which better for conduction?
which is better for insulation?
low- less energy needed to change temp
high- more energy needed
low
high
definition of specific latent heat?
unit?
amount of energy needed to change the state of 1kg of subsatnce without a change in temperature
J/kg
difference between specific heat capacity and specific latent heat?
specific heat capacity involves temp
latent heat- changes state WO temp change
why does temperature stay constant when changing state?
energy transferred or away from substance changing state ONLY changes the internal energy not temperature
- energy being used to overciome intermolecular forces of attraction
latent heat ^
types of latent heat and what for?
fusion- melt/ freeze
vapourisation- boil/condense
why does an increased temperature increase the pressure in a fixed volume?
increasing temperature -> kinetic energy increased -> speed increased -> no. collisons against walls increase (more frequent collsions)
unit of pressure
Pa= pascals
if temp & mass stayed constant in gas
how does compression affect pressure and volume?
how does expansion affect pressure and volume?
and why
- compressed- decreases volume -> increases density -> more collsions -> more force -> increase pressure
expanded- increases volume -> decreases density -> less collsions -> less forced exerted -> decrease pressue
pressure in gas
- molecules colliding with the wall exerts a force onto the walls
- the total force exerted by all the molecules- gas pressure
what is work?
transfer of energy by a force
