P1.2: Changes Of State Flashcards
What is density?
How much mass there is in a certain volume.
What is the difference in density between 2 different sized blocks made of the same material?
Nothing, density is the same for both
What is density a property of?
A material
What is the density formula?
Density (kg/m3) = mass (kg) / volume (m3)
Why would a substance in the solid state be denser than the same substance in a gaseous state?
1cm3 in the solid state have more particles than in 1cm3 of the same substance in a gas
How will the density be affected if there is a larger mass?
Higher density
How will the density be affected if there is a smaller mass?
Lower density
How will the density be affected if there is a larger volume?
Lower density
How will the density be affected if there is a smaller mass?
Lower density
What is the Law of Conservation Of Mass?
Particles do not disappear.
It applies if instances are condensing, melting, boiling etc.
Molecules do not disappear
What is temperature?
Tells you how hot or cold something is
What are the 2 units of temperature?
Celsius
Kelvin
How many celsius is there in 0 Kelvin?
-273 celsius
How many kelvins are there in 0 degrees celsius?
273 kelvin
What happens when you heat up water?
You transfer energy from the chemical store of the fuel to the thermal store of water
The particles of water move faster/vibrate more
The individual particles do NOT get hotter
Temperature tels you about…
The average kinetic energy of the particles
What is the energy in a thermal store measured in?
Joules
What 3 things can heating do?
Change the energy stored within the system to change the temp
Produce a change of state
Make a chemical reactions happen
What does the energy needed to raise the temp depend on?
Type of material
Mass of material
How much temperature needs to rise
What is specific heat capacity?
The energy needed to raise the temp of 1kg of a material by 1k.
What does heating do?
Heating increases the internal energy of the material
SHC formula?
Change in thermal energy (J) = mass (kg) x specific heat capacity (J/kg C) x change in temp (degrees C)
What can SHC tell you?
How resistant a material is to a change in temperature
What is the SHC of saucepans like and how does it benefit?
Saucepans are made of material with low SHC because they need to heat up quickly
What happens in larger SHC materials?
It’s harder to change its temp
What must you do in order to change the state of a substance?
Heat or cool
Explain the energy when water in lakes evapourate?
Energy is transferred from the thermal store of the surroundings to the water
Explain the energy when water in lakes condenses?
Energy is transferred from the water to the surroundings
Why doesn’t the temperature increase when boiling water?
When water boils, it stays at 100°C because all the heat is being used to turn the water into steam, not to make it hotter. The energy is busy breaking water molecules apart instead of raising the temperature.
Only after all the water becomes steam will the temperature start rising again.
What is specific latent heat of fusion?
The energy transferred when 1kg of a substance changes from the solid state to the liquid state, or vice versa
What is specific latent heat of vaporisation?
The energy transferred when 1kg is a substance changes from liquid to gas and vice verse
How do you calculate specific latent heat?
Thermal energy for a change in state (J) = mass (kg) x specific latent heat (J/kg)
What is the difference between SLH AND SHC?
SLH is about change of state
Heat capacity is about change of state
