P6 molecules and matter (paper 1) Flashcards
define the term density
the amount of mass in a certain volume
what is the equation for density
density (kg/m^3) = mass (kg or g) / volume (m^3 or cm^3)
what is the equation for volume
height x width x depth
what are changes of state caused by
heating or cooling the substance - in the case of heating this allows the particles to break the bond holding them together
describe the shape of a solid
fixed
describe the shape of a liquid and a gas
fills container
describe the volume of a solid or liquid
fixed
describe the volume of a gas
can be changed
which state has the highest density
solids
which state has the lowest density
gases
what does the density of an object depend on
- what its made of
- how its particles are arranged
describe the particles in a dense material
tightly packed together
if you compress a material what happens to its density
it gets more dense
why do materials get more dense after being compressed
- the mass doesnt change
- BUT the volume decreases
can you compress a solid
no
can you compress a liquid
no
why cant you compress a liquid
although particles are not fixed in position, they are still touching close together
describe the method to find the density of a solid object
- use a balance to measure its mass
- if a regular solid measure length, width, height with a ruler and calculates volumes with v = wlh
- for an irregular solid submerge it into a eureka can filled with water
- volume of water displaced is volume of solid
- calculate density using mass/volume
what is the name of apparatus used to measure the density of an irregular object
eureka can
describe the method to find the density of a liquid
- place measuring cylinder on balance and zero it
- pour 10ml of liquid in and record mass
- repeat until cylinder is full and record the total volume and mass each time
- for each measurement use d=m/v for density
- calculate average of values and that is the density
what is meant by the term ‘internal energy’
the energy stored by the particles making up a system
what energy stores do particles have and explain this
- kinetic energy = they vibrate and move around
- potential energy = their positions
what is the energy in a system stored by
its particles
what is meant by the term ‘internal energy of a system’
the total energy that its particles have in their kinetic and potential energy stores
how can you increase the internal energy of a system
heat it
why does heating a system increase the internal energy of it
particles gain energy in their kinetic stores and move faster
what does increase in internal energy lead to
- change in temperature
- change in state
if a temperature change occur what does the size of this change depend on
- mass of substance
- what its made of (specific heat capacity)
- the energy input
when does a change in state occur
when the particles are heated enough that they have enough energy in their kinetic stores to break the bonds holding them together
when bonds form (cool) what happens to the energy of particles
particles loose energy
what is the law when a substance changes state
mass is conserved
what is meant by the term ‘latent heat’
the energy needed for 1kg of substance to change its state without changing temperature
what set value for a substance is for change in temperature
specific heat capacity
what set value for a substance is used for change in state
latent heat
what are the two types of latent heat
- latent heat of fusion
- latent heat of vapourisation
what is latent heat of fusion
when a substance goes from a solid to a liquid
what is the latent heat of vapourisation
when a substance goes from a liquid to gas
what is the formula for latent heat and energy input for it with mass
E (J) = mass (kg) x latent heat of substance (J/kg)
E = mL
what is the forumla for electrical energy
E (J) = current (A) x time (s) x voltage (V)
what unit is used to measure pressure
Pascals (Pa)
state Boyle’s Law
volume is inversely proportional to pressure
what is the formula for Boyle’s law
- pressure x volume = constant
- pressure = constant / mass
what do colliding gas particles create…
pressure
explain how gas particles collidign creates pressure
- they move at high speeds
- when they collid with something or each other they exert a force
- in a sealed container the outward gas pressure is the total force exerted by all particles in the gas area
if gas particles are moving faster what will happen to the pressure
it will increase as it increases the ent force
if temperature is constant what does increasing the volume of a gas do to its pressure
decrease it
