# Understand Specific Heat Capacity

In this worksheet, students will explore the idea of heat and calculate the specific heat capacity of a given object. Key stage:  KS 4

Difficulty level:   ### QUESTION 1 of 10

Particles are vibrating all the time, moving around all over the place and bashing into their neighbours. We have a special scientific term for this -  we call it heat - I know, a super technical word you’ve never come across before. This is literally all that heat is -  just movement (or vibration) of particles. This means that we can get stuff really hot here on Earth. Did you know that the hottest place in the solar system is not the Sun, but a place called JET in Oxford! It's reached temperatures of over 50 million degrees – that's over 20 times the temperature of the Sun. Okay, so we know that when we get stuff really hot, all we are really doing is making the particles move around more – but did you know that some particles are harder to make move than others? Anyone who has put a pan of water on the stove to boil will tell you it takes AGES, but what about making a chunk of metal reach this same temperature? Well, it takes much less time thanks to something we call 'specific heat capacity' (or SHC for short).

SHC is literally just a measurement of the amount of energy it takes to heat up 1 kg of a material by 1 oC, and it has the unit of (are you ready for this) -  joules per kilogram degrees Celsius (J/kg oC). We can work this out by using the following equation:

energy transferred = mass × specific heat capacity × temperature change

To be really helpful, you will NOT need to remember this equation in the exam – you’ll just need to make sure that you can remember which number is which!

So, let’s go through an example question and how you might answer it:

A block of aluminium has a specific heat capacity of 900 J/kg oC and is heated from a starting temperature of 0 to a final temperature of 100 oC. The mass of the block is 4 kg. How much energy is transferred to the object?

You can answer a question like this in stages:

1   Find all of the numbers and highlight them:

A block of aluminium has a specific heat capacity of 900J/kg oC and is heated from a starting temperature of 0 to a final temperature of 100 oC. The mass of the block is 4 kg. How much energy is transferred to the object?

2   Now we need to find out where they all fit into the equation. Write them out and put the corresponding number next to them like this:

Mass = 4 kg

Specific heat capacity = 900 J/kg oC

Temperature change =  From 0 to 100

3   There is a temperature change, so work out what the difference is (super hard right?)

Mass = 4 kg

Specific heat capacity = 900 J/kg oC

Temperature change = 100 – 0 = 100 oC

4   Finally, write them into the equation, put the numbers in the calculator and press =

Energy = 4 x 900 x 100

Energy = 360,000 J

Don’t forget your units! And make sure you ALWAYS write out every step – this way the examiner can follow what you are thinking and might be able to give you some marks even if you don’t get the answer right.

Match the keywords to their meanings.

## Column B

SHC
The amount of energy it takes to heat up 1 kg of a...
Temperature
The total amount of kinetic energy of particles in...
Heat
How many particles there are in a substance
Mass
The average kinetic energy of the molecules

Describe how the motion of particles changes when you heat them up. (1 mark)

If an object needs more energy to heat up, then does it have a higher specific heat capacity or a lower one?

Higher

Lower

Match the symbol to the unit.

## Column B

Energy (E)
Degrees celsius (oC)
Mass (m)
Joules per kilogram degrees celsius (J/kg o
Specific heat capacity (c)
Kilograms (kg)
Change in temperature (Δθ)
Joules (J)

A man uses a stone to cook his food on. He puts the 1 kg stone on the fire, changing the temperature by 100 oC.

Calculate the energy that the fire supplied to the stone.

Specific heart capacity of stone = 790 J/kg oC.

The stone in the previous question is then used to cook steaks and cools down during this process. It reaches a temperature of 70 oC.

Calculate how much energy has been given to the steaks that had been put onto the stone.

Mass of the stone = 1 kg

Specific heat capacity = 790 J/kg oC.

Remember to leave one space and include the unit!

Define specific heat capacity.

A storage heater is a device that will be slowly heated during the day and then will release this heat during the night. Using the data below, choose a suitable material from which to make a storage heater, and explain your choice.  (3 marks)

 Material Specific heat capacity / J/kg oC. Melting point / oC. Copper 385 1200 Granite 790 2400 Water 2400 0 Ceramic 1200 2400

Which of the following is the specific heat capacity equation?

Energy = mass x specific heat capacity x change in temperature

Energy = mass x specific latent heat

Energy = 0.5 x mass x velocity2

Energy = 0.5 x spring constant x extension2

Water has a very high specific heat capacity and this means that it can absorb a lot of heat energy and transport it around the Earth in the form of water currents. In the UK, we have a stream of hot water that comes up from the Gulf of Mexico called the Gulf Stream. Due to climate change, however, this is slowing down and not giving the UK as much energy as it should.

Suggest some possible side effects of this. (2 marks)

• Question 1

Match the keywords to their meanings.

## Column B

SHC
The amount of energy it takes to ...
Temperature
The average kinetic energy of the...
Heat
The total amount of kinetic energ...
Mass
How many particles there are in a...
EDDIE SAYS
This was quite a challenging question to start with, wasn't it? How many did you get right? These are all scientific definitions that you might get asked, so you need to remember them. They come up quite often in exams, so get your learning brains on! Why not make your own learning poster for things like this and draw big pictures around them that will help you to remember them. They are seriously super important to remember!
• Question 2

Describe how the motion of particles changes when you heat them up. (1 mark)

EDDIE SAYS
When we are asked to describe things, keep it simple. You just need to say what will happen - no science, no maths - just a simple description of what is happening to the particles. You are speeding them up!
• Question 3

If an object needs more energy to heat up, then does it have a higher specific heat capacity or a lower one?

Higher
EDDIE SAYS
First of all, you need to think about what exactly is meant by specific heat capacity. Specific heat capacity is the measurement of how much energy it takes to heat up an object of a mass of 1 kg by 1 oC. This means that if you increase the amount of energy that it takes to heat up that substance, the only thing in the equation that you can change is the specific heat capacity. The higher the specific heat capacity, the more energy it takes to heat itself up.
• Question 4

Match the symbol to the unit.

## Column B

Energy (E)
Joules (J)
Mass (m)
Kilograms (kg)
Specific heat capacity (c)
Joules per kilogram degrees celsi...
Change in temperature (Δ&th...
Degrees celsius (oC)
EDDIE SAYS
You are going to see questions like this when there are multiple things that you need to remember. In this case, they will give you the equation, so all you need to remember is the units. Then all you need to do is plug those into the calculator in the correct order and you're flying! Easy marks!
• Question 5

A man uses a stone to cook his food on. He puts the 1 kg stone on the fire, changing the temperature by 100 oC.

Calculate the energy that the fire supplied to the stone.

Specific heart capacity of stone = 790 J/kg oC.

79,000 J
79000 J
EDDIE SAYS
Right, time to use that equation now. All you need to do is find the information and put it into the equation in the correct order. REMEMBER - always write down every step! That way if you make a mistake in the exam, you can still get some marks for it. Find the values and write them down: m = 1 kg c = 790 J/kg oC Δθ = 100 oC Put them into the equation: E = 1 x 100 x 790 E = 79000 J Remember the units!
• Question 6

The stone in the previous question is then used to cook steaks and cools down during this process. It reaches a temperature of 70 oC.

Calculate how much energy has been given to the steaks that had been put onto the stone.

Mass of the stone = 1 kg

Specific heat capacity = 790 J/kg oC.

Remember to leave one space and include the unit!

23,700 J
23700 J
EDDIE SAYS
This one is a little more difficult because you need to work out the change in temperature first. Let's have a look at how we do it: Write down all of the numbers: E = ? m = 1 kg c = 790 J/kg oC. Δθ = 100 - 70 = 30 oC. Now put them into the equation: E = 1 x 790 x 30 E = 23700 J Are you beginning to get the hang of these now?
• Question 7

Define specific heat capacity.

EDDIE SAYS
This is one of those definitions we've been talking about so much. You really need to remember the definition of specific heat capacity. There aren't any shortcuts here, you just have to remember it! The amount of energy it takes to heat up 1 kg of a substance by 1 oC.
• Question 8

A storage heater is a device that will be slowly heated during the day and then will release this heat during the night. Using the data below, choose a suitable material from which to make a storage heater, and explain your choice.  (3 marks)

 Material Specific heat capacity / J/kg oC. Melting point / oC. Copper 385 1200 Granite 790 2400 Water 2400 0 Ceramic 1200 2400

EDDIE SAYS
This is a common type of question that you get in exams. You will often be asked to look at a bunch of information and to select the one that is the most suitable. In a question like this, it is really important that you talk about every part of the table - you need to talk about both the specific heat capacity and the melting point. In this case, the best one would have been ceramic, because it has a high SHC and a high melting point. This means that it will be able to absorb a lot of energy during the day and release it during the night, and it won't be in danger of melting if it gets too hot.
• Question 9

Which of the following is the specific heat capacity equation?

Energy = mass x specific heat capacity x change in temperature
EDDIE SAYS
Did you recognise all of these equations?! They should all be on your list of ones to know! The word 'heat' in specific heat capacity should be a clue that it is something to do with temperature. Looking down the options, there are two equations that include something to do with heat or temperature. The correct one here is option one because option two is for specific latent heat which is not the same. Don't get them confused! Can you remember what the other two equations are for? Option three is the equation for kinetic energy and the final option is the equation for elastic energy. This was a good exercise in revision of all types of energy!
• Question 10

Water has a very high specific heat capacity and this means that it can absorb a lot of heat energy and transport it around the Earth in the form of water currents. In the UK, we have a stream of hot water that comes up from the Gulf of Mexico called the Gulf Stream. Due to climate change, however, this is slowing down and not giving the UK as much energy as it should.

Suggest some possible side effects of this. (2 marks)

EDDIE SAYS
Suggest is a word that means 'You have not been taught about this, but there is enough information for you to make a guess'. If you think these questions are hard, they are meant to be - this is the hardest type of question you'll be likely to do. Just have a go at it! In this case, it wants you to make a link between the heat coming from the Gulf Stream and the heat of the UK. If the Gulf Stream is slowing down, then there will not be as much heat coming to the UK, so there will be some obvious changes - the sea will be colder for example. There are also some less noticeable changes, for example, summers will be warmer because the Gulf Stream will not be cooling us down in the summer. 