Properties of Matter Flashcards
What is specific heat capacity
The specific heat capacity of a substance is the amount of heat energy needed to change the temperature of 1 kg of the substances by 1 degree celsius
every substance has a different value of specific heat capacity
What is the specific heat capacity formula?
Eh =c * m * Delta T
where:
Eh = heat energy measured in Joules (J)
c = specific heat capacity measured in joules per kilogram per degree celsius (J kg^-1 C^-1)
m = mass measured in kilograms (kg)
delta T = change in temperature measured in degrees celsius (C0)
Define heat
Heat is a form of energy. It causes the particles in a substance to move or vibrate. The faster they move, the more kinetic energy they have. This increaese the heat energy stored in the substance.
Heat energy is measured in Joules (J)
Define temperature
Temperature tells us how hot a substance is.
Temperature is a neasure of the average kinetic energy of the particles in a substance.
Temperature is measured in degree celsius (C0)
What are the three states of matter
Solid liquid and gas
When solids melt or liquids boil energy need to be
energy needs to be put in
When gases condense or liquids freeze energy is
energy is given out
What is specific latent heat
Specific latent heat is the heat energy required to change the state of 1kg of a substance.
What is significant about a change in state
there is no change in temperature
What is the specific latent heat formula
Eh = ml
where:
Eh = Heat energy measured in Joules (J)
m = mass measured in kilograms (kg)
l = latent heat measured in joules per kilogram (Jkg^-1)
What does specfifc latent heat of vaporisation of materials apply to?
This applies when:
a liquid change into a gas
and
a gas changes into a liquid
What does specific latent heat of fusion of materials apply to?
This applies when:
a solid changes into liquid
and
a liquid changes into a solid
What is pressure
Pressure is defined as the force acting per unit area.
What is the pressure formula
p = F/A
where:
p = pressure measured in pascals (pa)
F = force measured in newtons (N)
A = area measured in metres square (m^2)
What is 1 atmosphere in pascals
100,000 pascals
What is gas made up of?
Gases are made up of tiny particles - atoms or molecules - that are widely seperated and moving at a speed.
What is the volume of a gas
The volume of a gas is the volume of the container it is in - usually measured in cm ^3 or m^3.
Volume is not equal to mass.
What is the pressure of a gas
the pressure of a gas is the particles collding. This applies a force over the area of the contrainer - so we have a pressure.
What is the temperature of a gas
The temperature of a gas is a measure of the kinetic energy of the particles.
The faster the particles are moving, the higher the temperature of the gas.
What is Boyle’s law
For a gas of fixed mass, pressure is directly proportional to 1/volume.
pV = k
when using boyle’s law you will usually have to use:
p1V1 = p2V2
where:
p = pressure
V = volume
What is the pressure temperature law (gay lussac law)
When temperature is measured in Kelvin:
pressure is directly proportional to temperature
p1/T1 = p2/T2
p = Pressure measured in pascals (Pa)
T = temperature measured in Kelvin (K)
What is absolute zero?
absolute zero is 0 Kelvin. We know that at 0K the pressure of a gas is zero. This means the particles have stopped moving (pressure is caused by particles moving)
because the particles can’t move any less this must be the lowest possible temperature.
Absolute zero is the lawest temperature there can be.
How do you convert degrees celsius into Kelvin
Add 273
How do you convert Kelvin into degrees celsius
subtract 273
What is the volume temperature law (Charles’ law)
Volume is directly proportional to temperature measured in kelvin
V1/T1 = V2/T2
Where temperature is measured in Kelvin(K)
rule for temperature difference between kelvin and celsius?
A temperature difference of 1 degree celsius is identical to a difference of 1 Kelvin
What is the general gas equation
pV/T = k
or
p1V1/T1 = p2V2/T2
where:
p = pressure (Units in question)
V = volume (Units in question)
T = temperature which must be measured in Kelvin (K)
k is a constant
When do we use the general gas equation
We can use this if pressure, volume and temperature are all changing.
Describe the Charles’ law experiment
Place a sealed flask connected to a syringe in a beaker of water. Place a thermometer in the water.
Record the volume of the gas using the syringe
Record the temperature of the water (and therefore gas) using the thermometer.
Heat the water using a Bunsen burner. Turn off the Bunsen and record the volume and temperature of the gas.
Repeat this a number of times.
Describe the boyle’s law experiment
Set up the apparatus as shown in the diagram.
Disconnect the plastic tube and adjust the syringe so that it is half full of air. Reconnect the plastic tube
Adjust the syringe so that the volume of air is maximum.
Keep the syringe at this position for a period of time before noting the pressure reading to allow the temperature of the trapped air to return to room temperature. Note the pressure of the gas.
Adjust the volume a number of times by moving the plunger and note the corresponding pressure readings
the results of pressure * volume should all be the same
Describe the gay lussac law experiment
Place a sealed flask connected to a pressure sensor in a beaker of water. Place a thermometer in the water.
Record the pressure of the gas using the pressure sensor.
Record the temperature of the water (and therefore gas) using the thermometer.
Heat the water using a Bunsen burner. Turn off the Bunsen and record the pressure and temperature of the gas.
Repeat this a number of times.
