1. S4 Chemistry Rates of Reaction
NEW LEARNING
Average Rate of Reaction Calculated from a Graph
National 5
REVISION
Reactions monitored and graphs interpreted

2. Starter Questions
S3 Revision

3. Starter Questions
Name some common gases you have used or tested in science.
Carbon dioxide, hydrogen, oxygen, nitrogen, methane etc.
Are there any special properties of these gases that could help you identify them?
Mostly they are colourless and odourless.
3. Do you know of any poisonous gases?
Carbon monoxide, hydrogen cyanide, mustard gas.
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4. Lesson 1: Gas Reactions Today we will learn to
Identify gases produced by their chemical tests.
We will do this by
Reviewing our S2 science tests for gases and making some new gases using chemical reactions.
We will have succeeded if
We can identify all the gases we make..

5. Result of a Positive Test
Testing Gases
Testing Gases
In order to produce a foam fire extinguisher you will need to be able to produce carbon dioxide gas. There are many reactions that produce gases but not all produce carbon dioxide; some produce hydrogen and others oxygen. It is therefore important that we can identify carbon dioxide when it is produced.
Activity 1.1 Testing Gases
Your teacher will show you how to test for the gases: oxygen, hydrogen and carbon dioxide.
Gas
Result of a Positive Test
Oxygen
Hydrogen
Carbon dioxide

6. Testing Gases

7. Making Gases Solids Solutions Magnesium Hydrochloric acid
Activity 1.2 Making Gases
Your teacher will give you a number of solutions and solids. You will need to work out which combinations will produce carbon dioxide gas. You are only allowed to react one solution with one solid. The table below shows you the chemicals that you can use.
Solids
Solutions
Magnesium
Hydrochloric acid
Sodium hydrogencarbonate
Citric acid
Manganese dioxide
Hydrogen peroxide
Marble chips

8. What did you make?
Reaction
Name of Gas Produced

9. What did you make?

10. Explain why this student statement is wrong…
Exit Task
Mr Wrong
Explain why this student statement is wrong…
“Gases, like most chemicals, can be identified by their smell and colour”
Pupils could answer this, and if time, do some examples using the show me boards.

11. Starter Questions
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12. Starter Questions
What signs tell us a gas is being produced in a chemical reaction?
Bubbles, fizzing, sometimes colour or smell.
How would you test for oxygen gas?
Relights a glowing splint
What would happen if this test was tried with nitrogen?
It would go out, just as it would with many other gases.
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13. Lesson 2/3: Measuring the Speed
Today we will learn to
Measure the speed of a chemical reaction using a gas given off.
We will do this by
Plotting a graph of experimental results and calculating speed (or RATE)
We will have succeeded if
We can describe different ways of following a reaction and do a calculation to work out average rate

14. Measuring the Speed
As well as knowing the best combination of chemicals to produce the carbon dioxide we also need to know how fast the carbon dioxide is being produced so that we can work out whether any changes we make to our system are causing it to produce the gas more quickly.
The speed of a car is usually given in km per hour or miles per hour, this is really the distance travelled in one hour. If a car had a speed of 60 miles per hour it could travel 60 miles in one hour or 30 miles in half an hour or 120 miles in two hours.
So distance = speed x time
Or speed = distance
time

15. Measuring the Speed
The speed or rate of a chemical reaction can be measured in a similar way. In a reaction that produces a gas, the mass of the container in which the reaction takes place will decrease as the gas escapes. We can use the initial mass of the reaction container to work out the mass of gas produced.
So rate = mass of gas produced
time
In order to work out the rate of a reaction we need to know how much gas is being lost over the time the reaction goes on for.

16. Measuring the Speed Activity 1.3 Measuring the Mass of Gas Produced
.Pour 50cm3 of 1moll-1 HCl into a conical flask, put a piece of cotton wool in its mouth and place on a balance.
.Using a small beaker, weigh out 10g of marble chips and place it on the balance as well.
.Record the initial mass in the following table.
.Take out the cotton wool and pour in the marble chips, start the stop watch and replace the cotton wool.
.Measure the mass every 30 seconds and put your results in the table.

17. Measuring the Speed Time (min) Mass of container (g)
Mass of gas produced
(g)
0.00
8.0
0.5
8.5
1.0
9.0
1.5
9.5
2.0
10.0
2.5
10.5
3.0
11.0
3.5
11.5
4.0
12.0
4.5
12.5
5.0
13.0
5.5
13.5
6.0
14.0
6.5
14.5
7.0
15.0
7.5
15.5

18. Measuring the Speed

19. Measuring the Speed

20. Measuring the Speed

21. Average rate = change in mass
Measuring the Speed
Average rate = change in mass
time interval

22. Measuring the Speed DISCUSS
After discussion with your teacher and others can you think of other ways that the reaction between marble chips and hydrochloric acid can be followed.
NOTES
In the space below write down your ideas and draw diagrams to show different ways you would follow the reaction between marble chips and hydrochloric acid:

23. Measuring the Speed

24. Objective Traffic Lights
How do you feel about the lesson objectives?
Red = don’t think I have grasped this
Amber = feeling OK about this, have just about got there
Green = Confident I have achieved this
If there are no coloured cards available (e.g. in planners), Mark corners in the room for each colour and ask pupils to move to indicate confidence.

25. Starter Task
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26. Starter Task
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27. Starter Task
Complete Quick Test 1 in your booklet and we will review as a class. You have 5 minutes! Circle the correct answers.
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28. Answers Quick Test 1 1. D, 2. C, 3. D Ask 3, Then Me!
Mark your answers and check with neighbours to see why you got any wrong.
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29. Lesson 4/5: Increasing the Speed
Today we will learn to
Explain how changing particle size, concentration or temperature can change the speed of a reaction.
We will do this by
Designing experiments to investigate these changes and plotting graphs of the results.
We will have succeeded if
We can write an investigation report summarising our experiment.

30. Increasing the Speed
In order for a reaction to occur reactant particles must collide.
To speed up a reaction we therefore need to increase the number of collisions taking place, the more collisions taking place, the more products can be produced

31. Increasing the Speed

32. Increasing the Speed DISCUSS
After discussion with your teacher and others can you think of ways that you could increase the number of collisions taking place in the reaction mixture.
NOTES
In the space below write down your ideas:

33. Increasing the Speed Increasing Surface Area
A reaction’s speed can be altered by increasing the surface area of one of the reactants. This can be achieved by breaking up lumps into chips or even better grinding it into a powder. When this occurs more of the reactant’s particles are exposed and therefore more particles can come in contact with the other reactant. This means that there will be a greater number of collisions, resulting in a faster rate of reaction.

34. Increasing the Speed Increasing Concentration
A reaction’s speed can be altered by increasing the concentration of a solution or pressure in a gas. When this occurs there are more reactant particles in a given volume of space and therefore more particles can come in contact with the other reactant. This means that there will be a greater number of collisions, resulting in a faster rate of reaction.

35. Increasing the Speed Increasing Temperature
A reaction’s speed can be altered by increasing the temperature of the reaction mixture. When this occurs all the reactant particles have more energy and therefore more speed so a much greater number will collide more often and with more energy. This means that there will be a greater number of collisions, resulting in a faster rate of reaction.

36. Marks for Investigations in S4
Assessment Standard
Evidence Required
Evidence Produced
1.1 Planning an experiment/practical investigation
a Aim of experiment
b Dependent/Independent Variable
c Variables to be kept constant
d Measurements /observations to be made
e Resources
f Method including safety
1.2 Following procedures safely
a Procedures have been followed correctly
b safely carried out
1.3 Making and recording observations /measurements correctly
a correct observations
b correct measurements
1.4 Presenting results in an appropriate format
Results have been presented in an appropriate format (with units!)
1.5 Drawing valid conclusions
What the experiment shows, with reference to the aim
1.6 Evaluating experimental procedures
Explain why a suggestion given will improve the experiment

37. Increasing the Speed Activity 1.4 Effect of Surface Area
After looking at the available chemicals and equipment and discussion with others in your class and your teacher, devise an experiment that would show clearly and fairly that increasing the surface area of a solid reactant speeds up the reaction.

38. Increasing the Speed Activity 1.5 Effect of Concentration
After looking at the available chemicals and equipment and discussion with others in your class and your teacher, devise an experiment that would show clearly and fairly that increasing the concentration of a reactant solution speeds up the reaction.

39. Increasing the Speed
Activity Effect of Temperature
After looking at the available chemicals and equipment and discussion with others in your class and your teacher, devise an experiment that would show clearly and fairly that increasing the temperature speeds up the reaction.
Choose one experiment from Activity 1.4, 1.5 and 1.6 to complete for your investigation. Write your aim and method, including any safety precautions you should take.

40. Pyramid Exit Task Question you have about the lesson
Things you have been reminded of today
Things you have learned today

41. Starter Activity
Complete your plan for the experiment – you have 10 minutes!
Check your plan against the mark scheme for an investigation in S4. Will it pass all the requirements?
If not, change your plan and get your teacher to check it before beginning your experiment. Remember you’ll need a table for your results.

42. Marks for Investigations in S4
Assessment Standard
Evidence Required
Evidence Produced
1.1 Planning an experiment/practical investigation
a Aim of experiment
b Dependent/Independent Variable
c Variables to be kept constant
d Measurements /observations to be made
e Resources
f Method including safety
1.2 Following procedures safely
a Procedures have been followed correctly
b safely carried out
1.3 Making and recording observations /measurements correctly
a correct observations
b correct measurements
1.4 Presenting results in an appropriate format
Results have been presented in an appropriate format (e.g. Table or graph, with units!)
1.5 Drawing valid conclusions
What the experiment shows, with reference to the aim
1.6 Evaluating experimental procedures
Explain why a suggestion given will improve the experiment

43. Measuring the Speed Activity 1.3 Measuring the Mass of Gas Produced
.Pour 50cm3 of 1moll-1 HCl into a conical flask, put a piece of cotton wool in its mouth and place on a balance.
.Using a small beaker, weigh out 10g of marble chips and place it on the balance as well.
.Record the initial mass in the following table.
.Take out the cotton wool and pour in the marble chips, start the stop watch and replace the cotton wool.
.Measure the mass every 30 seconds and put your results in the table.

44. Produce a mind map to summarise the lesson today.

45. Starter Activity

46. Starter Activity Work in pairs.
Activity Rates of Reactions Sentences Game
Work in pairs.
Make paragraphs from the sentences and match them to the correct illustrations.
Summarise your paragraphs in the space on p13 of your notes.

47. Lesson 6: Rates Graphs Today we will learn to
Explain the shape of rates graphs
We will do this by
Investigating different graphs in groups and solving problems on them.
We will have succeeded if
We can make statements about reaction speed based on graph shapes.

48. Rates Graphs Shapes of Graphs
During the course of a reaction the steepness of the curve changes, getting less steep as reactants are used up and the speed of reaction slows down. For a reaction producing a gas the shape will tend to look like this graph:
However the steepness of the curve will change if we alter either the surface area of the solid, concentration of acid or the temperature.

49. Rates Graphs
If the surface area, concentration or temperature are increased: 

50. Rates Graphs
If the surface area, concentration or temperature are decreased: 

51. Rates Graphs
1. If graph A represents experiment 1 below, in pairs look at the remaining graphs and match them to the correct experiment.
2. Once you have reached a decision with your partner, check with another pair to see if you agree.
Note: Some graphs may be used more than once!

52. Rates Graphs
Answers
The graph which is most likely to be produced from experiment 2 is Graph C
The graph which is most likely to be produced from experiment 3 is Graph A
The graph which is most likely to be produced from experiment 4 is Graph D
The graph which is most likely to be produced from experiment5 is Graph D .
The graph which is most likely to be produced from experiment 6 is Graph B

53. Exit Task Shape and Colour
Use only shape and colour to create an image of one thing you have learned today
Then, show it to a partner and see if they can guess what the learning is.

54. Starter Task
Complete Quick Test 2 in your booklet and we will review as a class. You have 5 minutes! Circle the correct answers.
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55. Answers Quick Test 2 1. B, 2. B, 3. C Ask 3, Then Me!
Mark your answers and check with neighbours to see why you got any wrong.
S3 Revision

56. Lesson 7: Research Task In this lesson we will learn to…
Carry out research on a useful chemical and report on it to show the effect of its use on society.
We will do this by…
Examining some sources of information on fire extinguishers or other foam products and discussing how they would be used.
Lesson 4 (cont)
We will have been successful if…
We can explain what a good report on fire extinguishers or other foam products would include.

57. What should my report look like?
Your report must
Be words long.
Include a description of the chemical reaction or product you have picked, what it is used for and why it is useful.
Include the effect this chemical (and its use) have had on society or the environment. This might be a good effect, or a bad effect, or a mixture of both.
Give your report a clear structure e.g. titles and subtitles. You can use your own version of diagrams if you want, but DO NOT cut and paste, or you will not pass.
NB This slide contains 101 words.

58. Where can I find information on gas reactions?
Gases are produced from reactions in products such as:
Fire extinguishers
Hair Mousses
Shaving Foams
Use the fact files provided for information.
The fact files have links to you tube, how stuff works and how it’s made.
You can google the links on PCs/Phones or at home for extra information.

59. Tell me three things...
you have done well you would like to find out more about you know now that you didn’t know 50 minutes ago

60. Lesson 7: Making Foam Research Task
After discussion with your teacher and others can you find out how foams are made in commercial foam fire extinguishers. Shaving foam and hair styling mousse are also foams, can you find out how these are made.
Activity Making Foam
After looking at the available chemicals and equipment and discussion with others in your class and your teacher identify the best way of producing lots of foam.
S3 Revision

61. Lesson 8: Making a Fire Extinguisher!
Today we will learn to
Apply lots of chemistry to design a product!
We will do this by
Designing and building a fire extinguisher
We will have succeeded if
We can put out a small fire with our extinguisher.

62. Making a Fire Extinguisher
DISCUSS
After discussion with your group plan how you are going make your foam fire extinguisher. You will need to consider the following points:
.How will you keep your gas generating chemicals apart?
.How will you ensure the foam producing chemicals come in contact with the gas when it forms?
.How will you direct the foam at a fire?
NOTES
In the space below write down your ideas and draw a diagram of your final design:

63. Definition
Choose three new words you have learnt in this topic and write dictionary definitions.