1. EXPLAINING A HEATING CURVE FOR ICE, WATER & STEAM

2. FIRSTLY WE NEED TO REMEMBER THE 3 STATES OF MATTER INVOLVED:
ICE
STEAM
WATER

3. AND THE CHANGES OF STATE THAT OCCUR DURING HEATING:
ICE
MELTING
EVAPORATION
WATER
STEAM

4. We follow the temperature as we heat up the ice using the apparatus shown below
Thermometer
HEAT

5. We record the temperature in the beaker as the ice is heated on a graph
Temperature (ºC)
Time (Seconds)

6. As we heat the solid the temperature rises steadily
It then levels off as the solid melts
Temperature (ºC)
Time (Seconds)

7. As the temperature goes up again, we’re heating the gas
The liquid is then heated steadily
Temperature (ºC)
Until it levels off as the liquid boils
Time (Seconds)
As the temperature goes up again, we’re heating the gas

8. These graphs can then be used to find the melting and boiling points of the chemical being heated up
Time (Seconds)
Gas
Boiling Point
Liquid
Melting Point
Solid

9. WHY DO WE GET THE LEVELLING OFF AREAS?
Time (Seconds)
Gas
Liquid
Solid
As the change of state happens energy is absorbed to break bonds between the particles in the solid & so the temperature doesn’t rise until they all broken!!

10. FREEZING POINT = MELTING POINT
Of course we can do COOLING CURVES as well, to look something like this
Gas
Boiling Point
Liquid
Freezing Point
Solid
REMEMBER
FREEZING POINT = MELTING POINT
OF LIQUID OF SOLID

11. WE ARE DOING THESE CHANGES OF STATE
ICE
FREEZING
CONDENSATION
WATER
STEAM