Use the specific heat capacity formula to answer the following: 1) How much heat is required to raise the temperature of 2kg of lead by 30°C if the specific heat capacity of lead is 130 J/kg°C? 2) What is the specific heat capacity of paraffin if 2200J raises the temperature of 0.1kg from 10°C to 20°C?

Learning Objectives By the end of this lesson you should… Be able to describe the change in temperature of a substance as heat energy is supplied or removed Understand qualitatively and quantitatively the concept of the specific latent heat of a material. Be able to explain the variation in temperature in terms of intermolecular forces

EXTENSION – include temperature values on your axis Learning Objectives By the end of this lesson you should… Be able to describe the change in temperature of a substance as heat energy is supplied or removed Understand qualitatively and quantitatively the concept of the specific latent heat of a material. Be able to explain the variation in temperature in terms of intermolecular forces YOUR TASK: On a post-it-note sketch a graph of temperature against time for ice (-50°C) being turned into steam (150°C) EXTENSION – include temperature values on your axis

Now complete the experiment following the method provided Learning Objectives By the end of this lesson you should… Be able to describe the change in temperature of a substance as heat energy is supplied or removed Understand qualitatively and quantitatively the concept of the specific latent heat of a material. Be able to explain the variation in temperature in terms of intermolecular forces Now complete the experiment following the method provided The plot of your results will provide you with a section of your sketch graph. When you are finished compare the results – does the pattern match? If not, why not? If so then how did you know?

This flat line shows where energy is being used to push the particles further apart and break the final intermolecular bonds Temp/OC This slope shows how energy is being used make molecules vibrate more and move faster so further increasing the KE of molecules 150 100 50 -50 This slope show how energy is being used make molecules move faster – NO intermolecular bonds left Is this a heating curve for ice? Write a description of what is happening at each stage of this heating curve. You also need to estimate /calculate energy input needed at each stage on graph This slope shows how energy is being used make molecules vibrate more and so increase KE of molecules Time/s This flat line shows where energy is being used to break intermolecular bonds – this has to be done during melting

Condensing water 150 Temp/OC 100 50 Time/s -50 -50 As the question what happens to latent heat when steam condenses all freezes? Heat energy is given out. Time/s

LATENT HEAT Energy needed to break bonds and melt or boil Learning Objectives By the end of this lesson you should… Be able to describe the change in temperature of a substance as heat energy is supplied or removed Understand qualitatively and quantitatively the concept of the specific latent heat of a material. Be able to explain the variation in temperature in terms of intermolecular forces Energy needed to break bonds and melt or boil a material is known as LATENT HEAT Hidden: Additional heat energy doesn’t show as temperature change

The energy required to change the state of 1kg of a substance Learning Objectives By the end of this lesson you should… Be able to describe the change in temperature of a substance as heat energy is supplied or removed Understand qualitatively and quantitatively the concept of the specific latent heat of a material. Be able to explain the variation in temperature in terms of intermolecular forces Specific Latent Heat The energy required to change the state of 1kg of a substance Specific latent heat of fusion = melting or freezing Specific latent heat of vaporisation = boiling or condensing

Learning Objectives By the end of this lesson you should… Be able to describe the change in temperature of a substance as heat energy is supplied or removed Understand qualitatively and quantitatively the concept of the specific latent heat of a material. Be able to explain the variation in temperature in terms of intermolecular forces A jeweller wants to melt 100 g of silver. The specific latent heat of fusion for silver is 100 000 J/kg. How much energy will be required? Energy = mass x specific latent heat m = 100g = 0.1 kg L = 100,000J/kg E =mL E =0.1 x 100 000 =10 000J = 10kJ

Learning Objectives By the end of this lesson you should… Be able to describe the change in temperature of a substance as heat energy is supplied or removed Understand qualitatively and quantitatively the concept of the specific latent heat of a material. Be able to explain the variation in temperature in terms of intermolecular forces YOUR TASK: Calculate the energy required to change the temperature of 1kg of ice from -50˚C to 150˚C

Temp/OC 150 100 50 -50 210,000J 2,260,000J 420,000J More energy to boil water than melt it – breaking 2 bonds during melting and rest during boiling. 330,000J Time/s 210,000J

Name that key term... Learning Objectives By the end of this lesson you should… Be able to describe the change in temperature of a substance as heat energy is supplied or removed Understand qualitatively and quantitatively the concept of the specific latent heat of a material. Be able to explain the variation in temperature in terms of intermolecular forces Name that key term...

The amount of energy required to raise the temperature of 1kg of a substance by 1˚C

The temperature at which a substance turns from liquid to gas

These are present in solids and liquids but not in gases

A picture that uses colour to represent different temperatures

The point reached when all temperatures are equal