MODULE mod7A mod7B mod7C mod7D mod7E mod7F mod7G mod7H mod7I mod7J mod7K mod7L mod8A mod8B mod8C mod8D mod8E mod8F mod8G mod8H mod8I mod8J mod8K mod8L mod9A mod9B mod9C mod9D mod9E mod9F mod9G mod9H mod9I mod9J mod9K mod9L 9fa1
9Fa1 Hotting up 1
Name _____________________________ Class ____________
In these experiments you will find out what affects the amount of heat given off. When calcium reacts with water the tube gets hot.
Experiment 1: Changing the amount of calcium
Apparatus
- Boiling tube - Thermometer - Tube rack
- Measuring cylinder - Eye protection
- Calcium granules (from your teacher)
Method
1 Measure out 10 cm3 of water in the measuring cylinder.
2 Pour it into the boiling tube.
3 Measure the temperature of the water and write it in the table.
4 Ask your teacher for a piece of calcium. Your teacher will drop it into the water.
5 As soon as the reaction is finished, measure the temperature of the liquid.
6 Wash out your tube.
7 Repeat the experiment with two pieces of calcium, and then three pieces.
Do not touch the pieces of calcium. Your teacher will handle the calcium using forceps.
Wear eye protection.
Recording your results
Pieces of calcium
Water temperature at the start (°C)
Water temperature at the end (°C)
Temperature rise (°C)
1
2
3
Considering your results/conclusions
The more pieces of calcium we used ________________________________________________ .
The factors that were the same each time were ________________________________________ .
It was a fair test because _________________________________________________________ .
Experiment 2: Changing the volume of water
1 Measure out 5 cm3 of water in the measuring cylinder.
7 If you have done experiment 1, write the result for 10cm3 of water into your table. If you have not done this experiment already, do it now.
8 Repeat the experiment with 15 cm3 of water.
Volume of water (cm3)
Water temperature the start (°C)
Temperature rise (oC)
5
10
15
The more water we used _________________________________________________________ .
[ observing, considering ]
9Fa2 Hotting up 2
In these experiments you will find out what affects the amount of heat given off when calcium reacts with water.
Preliminary experiment
- Boiling tube - Thermometer
- Calcium granules - Tube rack
(from your teacher)
1 Measure 10 cm3 of water and pour it into the boiling tube.
2 Measure the temperature of the water.
3 Ask your teacher for a piece of calcium. Your teacher will drop it into the water.
4 When the reaction is finished, measure the temperature of the liquid.
Planning
Now plan an investigation which will look at how the temperature rise might be affected by:
- the number of pieces of calcium that you use
- the volume of water.
1 Write a plan. You will need to think about:
- whether you will investigate one variable or both
- how many experiments you need to carry out
- the range of values that you will investigate (e.g. What is the maximum volume of water? What will be the difference in water volume between one test and the next?)
- how you can check your results. (Is it possible to co-operate with other groups and swap data?)
Predictions
2 Predict how the temperature rise will be affected by:
a the volume of water
b the amount of calcium.
3 Explain your reasoning. Is it possible to predict the actual temperature that might be reached in each case?
4 Carry out your experiment and record your results in a neat table.
5 If you have enough results, draw a graph or graphs to display your results.
6 What factors affect the temperature rise?
7 Are there any definite number patterns in the results?
8 Did this agree with your predictions?
9 Can you explain the findings using scientific reasons?
Evaluation
10 Which factors did you keep the same each time?
11 a In what ways was the test not completely fair?
b How might this be overcome?
12 a Did you have enough results?
b Did all the results fit the general trend?
13 Are you fully confident of your conclusions, or do you need to check your data, or try any extra experiments to confirm your ideas?
[ planning, observing, presenting, considering, evaluating ]
9Fa3 Reactions with water
aluminium
Al
No reaction with cold or hot water. Will react with steam to produce aluminium oxide and hydrogen.
magnesium
Mg
Very slow reaction with cold water. Slow reaction with hot water. Reacts readily with steam to form magnesium oxide and hydrogen.
calcium
Ca
Reacts rapidly with cold water. Hydrogen gas is given off. The water turns milky white.
potassium
K
Violent reaction. Potassium floats on the surface of the water, melts and then catches fire. Burns with a lilac coloured flame. Hydrogen gas given off.
copper
Cu
No reaction with cold or hot water. No reaction with steam.
silver
Ag
gold
Au
sodium
Na
Rapid reaction. Sodium floats on water, and moves around rapidly. Heat from the reaction melts the sodium. Hydrogen gas given off.
iron
Fe
Iron will rust slowly in cold water.
zinc
Zn
No reaction with cold or hot water. Will react slowly with steam to produce zinc oxide and hydrogen.
[ knowledge ]
9Fa4 Metals and water 1
1 Some metals react with water and others do not. Unscramble the letters to get the correct metal.
a I do sum floats on water and reacts very quickly to form an alkali
______________________
b Mega minus burns with a bright white flame and reacts very slowly with cold water
c Orni goes rusty if you leave it in water ______________________
d Imacluc reacts quickly with water and makes the water go white
e Pc rope is used for piping because it does not react with water
2 Put the five metals in order, from the most reactive to the least reactive.
1 ____________________ 2 ____________________ 3 ____________________
4 ____________________ 5 ____________________
3 Emma did an experiment in which she looked at the reactions of metals in air. She got these results: sodium (most reactive), magnesium, calcium, iron, copper (least reactive). How do Emma's results compare with your answer to question 2? Tick the correct box.
The order is exactly the same.
The order of reactivity is roughly the same, but there are some differences.*
The order is totally different.*
*If you ticked one of these boxes, say what the differences are here:
__________________________________________________________________________
4 Complete the word equations for these reactions. Here is an example:
sodium + water → sodium hydroxide + hydrogen
a calcium + water → calcium hydroxide + _______________
b _______________ + water → potassium hydroxide + hydrogen
c _______________ + _______________ → lithium hydroxide + hydrogen
9Fa5 Metals and water 2
1 Choose your answers from the words in the box. Each answer is used only once.
calcium copper iron lead magnesium potassium sodium
Give the name of:
a two metals which float on water and react very quickly to form alkalis
b a metal which burns with a bright white flame and reacts slowly with cold water
c a metal which goes rusty if you leave it in water
d a metal which reacts quickly with water and makes the water go white
e a metal which is still used for piping because it does not react with water
f a metal which used to be used for piping but is no longer used because of the risk of poisoning the water supply.
2 Look at the sketch of the Periodic Table.
Which section of the table includes:
a unreactive metals and non-metals
b the most reactive metals
c metals that are less reactive.
3 Two of the metals in the list below react with water, giving off a gas and producing metal hydroxides. The other two metals do not react.
sodium lead copper calcium
a Which two metals do not react?
b Write word equations for the reactions of the other two metals with water.
4 Carlton wrote in his exercise book:
Do you agree with Carlton or not? Explain your answer.
9Fa6 Looking for patterns
When metals react with oxygen they turn into metal oxides and they gain in mass.
Sanjay wondered whether the gain in mass might be linked to the reactivity of the metal.
Clare wondered whether there was any relationship between the gain in mass and the position of the element in the Periodic Table.
They collected the data in the table and tested their ideas. All the figures in the table refer to the mass of metal oxide formed when 10 g of metal was heated and completely converted into the metal oxide.
Meta-
Mass of oxide formed (g)
Increase in mass
Percentage increase
Atomic number
Order of reactivity
18.9
14.0
12.5
9
14.3
7
lead
10.3
8
16.7
4
14.2
13.5
6
1 Copy the table.
2 Work out the increase in mass for each metal.
3 Calculate this as a percentage (remember that you started with 10 g of each metal).
4 Plot a scatter graph showing the percentage increase in mass and the order of reactivity of the metals.
5 Look up the atomic number of each of the elements on the Periodic Table.
6 Plot a second scatter graph showing the percentage increase in mass against atomic number.
7 Were Sanjay's or Clare's ideas right? For each graph decide whether:
- there is a definite relationship between the variables, that applies to all the metals
- there is a relationship (a correlation) that applies to most of the metals - and if so, which elements do not fit the trend
- there is definitely no relationship between the variables.
8 How sure are you about the conclusions that you have drawn? Are there any other different elements that you could get data for, which would help you to come to more definite conclusions?
9 What important factor has not been considered at all in this analysis that may help to explain any anomalous results?
[ presenting, considering, evaluating ]
9Fb1 Reactions of metals with acids 1
Prediction
You will be using calcium, copper, iron, magnesium and zinc.
Make a prediction of the order of reactivity of these metals with acid, starting with the most reactive one.
1 ___________________ 2 ___________________ 3 ___________________
4 ___________________ 5 ___________________
- Test tube rack - Five test tubes
- Wooden splints - Eye protection
- Dilute hydrochloric acid - Bunsen burner
- Samples of calcium, copper, - Heatproof mat
iron, magnesium and zinc
1 Take a dry test tube to your teacher, who will give you a piece of calcium.
2 Fill a different test tube about 1/3 full with dilute hydrochloric acid.
3 Carefully tip the piece of calcium into the test tube containing the acid.
4 Add a piece of one of the metals.
5 If any gas is given off, test it with a lighted splint.
6 Feel the tube to see if it is warm.
7 Look to see if the metal has reacted in the acid.
8 Record your results in the table.
9 Repeat the test with other metals.
Use this table to record your results.
Metal
Did you get bubbles?
Did the gas burn with a pop?
Did the metal react?
Did the tube get warm?
How many metals reacted? __________
How many did not react? __________
What is the name of the gas that is given off ? __________________________________________
List the metals in order of reactivity, from the highest to the lowest.
1 ___________________________
2 ___________________________
3 ___________________________
4 ___________________________
5 ___________________________
How does this list compare with your predictions?
_______________________________________________________________________________
9Fb2 Reactions of metals with acids 2
How fast do different metals react with acid?
1 The metals that you will be using are calcium, copper, iron, magnesium and zinc. Based on the work that you have done so far, make a prediction of:
- the order of reactivity
- which metals will react, and which will not.
2 How can you compare the reactivity of different metals with acids?
3 What will you look for to tell you that a reaction has taken place?
4 What factors should you keep the same to make it a fair test?
5 Why is it difficult in this case to make the test completely fair?
- Test tube rack - Five test tubes - Bunsen burner
- Wooden splints - Eye protection - Heatproof mat
- Dilute hydrochloric acid
- Samples of calcium, copper, iron, magnesium and zinc
6 Write a method for your investigation. You could use some of the following apparatus.
7 Carry out your investigation, and record your results in a neat table.
8 List the metals in order of reactivity, from the highest to the lowest.
9 a Compare this list with:
- your predictions
- the reactivity of these metals with water and air.
b Note any similarities and differences.
10 Write word equations for the reactions that have taken place.
[ planning, observing, presenting, considering ]
9Fb3 Reactions of metals with acids 3
Steady reaction with acids giving off hydrogen gas, once the protective layer has been 'stripped off' by the acid.
Rapid reaction with acids giving off hydrogen gas. Heat from the reaction means that the tube will get warm.
Very rapid reaction with acids. Hydrogen gas is given off. Heat from the reaction means that the liquid in the tube gets hot.
Violently explosive reaction with acids. Potassium reacts with the acid forming hydrogen gas. This reaction should not be attempted in the laboratory.
No reaction with most dilute acids. Copper will react with concentrated acids.
No reaction with most dilute acids. Silver will react with some concentrated acids.
No reaction with any dilute acids. Only the strongest mixtures of concentrated acids will attack gold.
Very violent reaction with acids. Possibly explosive. Sodium reacts with the acid forming hydrogen gas. This reaction should not be attempted in the laboratory.
Slow reaction with dilute acids to produce hydrogen
Steady reaction with dilute acids to produce hydrogen.
9Fb4 Reactions with oxygen
No reaction when in block form unless heated very strongly indeed. Burns readily in powder form.
Magnesium ribbon burns brightly when heated in a flame. Magnesium powder burns very rapidly with a white flash.
Calcium pieces burn strongly if heated in a flame for several minutes.
Melts very easily and then catches fire. Burns very rapidly with a lilac coloured flame.
Metal glows red when heated in a strong flame but does not burn. There is a black coating on the metal at the end.
No reaction in a flame. Silver will melt if it is heated to a high temperature, but it will not burn. Will react very slowly with the air to form silver oxide.
No reaction. Gold will melt if it is heated to a high temperature, but it will not burn. It does not oxidise in the air.
Melts easily and then sets on fire. Burns rapidly with a yellow/orange flame.
No reaction in block form. Fine wire or filings will sparkle when put in a flame. Iron will rust slowly in moist air.
No reaction when in
block form. Burns in powder form.
9Fb5 Metals and acids 1
1 Draw lines to link the correct metal to each description
Which metal:
a reacts steadily with acids to give an orange-brown solution calcium
b reacts quickly with water and acids copper
c could explode if you reacted it with an acid iron
d does not react with water or acids magnesium
e reacts with acids and reacts very slowly with water sodium
2 When metals react with acids, which gas is given off? Circle the right answer.
hydrogen oxygen helium carbon dioxide
3 How do we test for this gas? Tick the correct box.
A
B
C
D
A Relights a glowing splint
B Turns lime water milky
C Burns with a squeaky pop
D Puts out a burning splint
4 You have got some sulphuric acid that you need to store.
You could store it in:
- a steel can
- a glass jar
- a plastic bottle.
a Which container is most likely to be corroded by the acid? ______________________
b Which container would be most likely to break if you dropped it? _________________
c Which container would be the lightest and most flexible? ________________________
d How would you choose to store the acid? ___________________________________
e Why? ________________________________________________________________
______________________________________________________________________
9Fb6 Metals and acids 2
1 When metals react with acids, a gas may be given off.
a Name the gas___________________________________________________________
b How do we test for this gas? ______________________________________________
2 Complete the word equations for these reactions. Here is an example:
calcium + hydrochloric acid → calcium chloride + hydrogen
a calcium + nitric acid → calcium nitrate + _________________
b _________________ + hydrochloric acid → zinc chloride + hydrogen
c magnesium + _________________ acid → magnesium chloride + hydrogen
d _________________ + sulphuric acid → iron sulphate + _________________
3 Put these formulae next to the correct acid in the table.
H2SO4 HCl HNO3
Acid
Chemical formula
nitric
sulphuric
hydrochloric
You could store it in a metal can, a glass jar or a plastic bottle.
Give advantages and disadvantages for each type of container, and say which one you think would be the best to choose.
Advantages of a metal can ____________________________________________________
Advantages of a glass jar ______________________________________________________
Advantages of a plastic bottle __________________________________________________
Disadvantages of a metal can __________________________________________________
Disadvantages of a glass jar ____________________________________________________
__________________________________________________________________________ Disadvantages of a plastic bottle ________________________________________________
Which would you choose? _____________________________________________________
Why? _____________________________________________________________________
9Fb7 Metals and acids 3
1 The symbol equation for the reaction of zinc with sulphuric acid is:
Zn + H2SO4 → ZnSO4 + H2
a How many atoms are there in a molecule of hydrogen gas?
b Name one compound in this equation that does not contain a metal.
c What is the name of the compound with the formula ZnSO4?
d This is a balanced equation. Explain the meaning of 'balanced' in terms of numbers of atoms.
e Write a similar balanced symbol equation equation for the reaction of magnesium with sulphuric acid.
2 The formula of zinc chloride is ZnCl2. Here is an equation which shows the formulae of all the substances that take part in the reaction:
Zn + HCl → ZnCl2 + H2
a Write the formulae for:
- the two reactants
- the two products.
b The equation above is not fully correct. It is not balanced. Explain why it is wrong.
The balanced equation is written like this:
Zn + 2HCl → ZnCl2 + H2
c This diagram illustrates the equation.
In the diagram, which symbol represents:
i an atom of zinc
ii an atom of hydrogen
iii a molecule of hydrogen?
d Kevin wrote that the correct symbol equation should be
Zn + HCl → ZnCl + H
Kevin's equation is balanced, but it is not correct. Explain why Kevin's equation is not correct.
9Fb8 Which metal reacts best?
The table shows the results of an experiment in which 0.2 g of metal was reacted with hydrochloric acid. The volume of gas given off was measured every 10 seconds until all of the metal had reacted.
Volume of gas (cm3) released by each metal
Time (s)
0
60
45
20
90
80
30
105
110
39
40
113
135
47
50
117
155
54
119
172
70
120
186
65
194
69
199
72
100
200
74
75
1 Plot a line graph of the volume of gas against time. Use a different line for each metal, and label the lines to show which metal is which.
2 When is the reaction of calcium the fastest - after 10, 20 or 30 seconds? Explain your answer by referring to the graph or table.
3 Explain why the reaction slows down as time goes on. You may find it helpful to use the particle model to help with your explanation.
4 List the three metals in order of:
a how quickly they react at the start of the reaction
b the order in which they stopped reacting
c the amount of gas produced by each metal.
5 a Why is it difficult to say which metal reacts 'best'?
b What would be a better word to use?
6 Explain as fully as you can why the magnesium line crosses over the calcium line.
7 What would you say is the best measure of reactivity - the speed of the reaction at the start or the amount of gas at the end? Explain your answer.
[ considering, presenting ]
9Fc1 Displacement reactions 1
In this experiment, you will investigate the reactions of metal elements with compounds of other metals.
1 Collect a copy of the results sheet (9Fc/2).
2 Choose a colour, and underline the four elements.
3 Choose a different colour, and underline the four compounds.
4 Fill in the key by your table to show the colours of the elements and compounds.
- Test tube rack - Test tubes
- Eye protection - Thermometer
- 3 pieces each of copper, iron, lead and magnesium
- Solutions of copper sulphate, iron sulphate, lead nitrate and magnesium sulphate
1 Take three test tubes, and fill them about 1/3 full with copper sulphate solution.
2 Add a small piece of iron to one tube, lead to the second tube and magnesium to the third tube.
3 Leave the tubes for several minutes. Check to see if there is any reaction. Look for:
- colour changes on the surface of the metal
- colour changes in the solution
- bubbles of gas given off
- a temperature rise.
4 Write your results in the table.
5 Repeat the experiment with the other solutions.
5 Add up the total number of reactions for each of the metals, and write it in the table.
6 Put the metals in order of reactivity.
7 Add up the total number of reactions for each of the compounds and write it in the table.
8 Put the compounds in order of reactivity.
9 How does the list of metals compare with the list of compounds?
10 Here is a word equation for the reaction of zinc with copper sulphate:
zinc + copper sulphate → copper + zinc sulphate
Write word equations for the reactions that took place in your experiments.
9Fc2 Displacement reactions results sheet
Results sheet
copper sulphate
iron sulphate
lead nitrate
magnesium sulphate
total reactions
X
total
Key
elements
compounds
Order of reactivity of metals: Order of reactivity of compounds:
1 ____________________________________ 1 ____________________________________
2 ____________________________________ 2 ____________________________________
3 ____________________________________ 3 ____________________________________
4 ____________________________________ 4 ____________________________________
9Fc3 Displacement reactions 2
- Pieces each of copper, iron, lead and magnesium
1 How many experiments are possible, if you are mixing one metal with one solution each time?
2 Put the four metals in order of reactivity.
3 Draw up a results table. Include a space in your table for a prediction.
4 If you think that a combination will react, put a tick in the table. If you think there will be no reaction, put a cross.
5 Carry out your experiments and record the results in your table.
6 Lay out your results in a way which allows you to see easily the number of reactions of each metal and each solution.
7 Add up the total number of reactions for each of the metals. Does this agree with the order of reactivity in your prediction?
8 Add up the total number of reactions for each of the compounds. Put the compounds in order of reactivity.
9 How does the reactivity of metals compare with the reactivity of the compounds?
10 Write word equations for the reactions that took place in your experiment.
9Fc4 Displacement reaction game rules
This is a game for 2-4 players.
You will need a pack of 36 cards. 24 of these cards represent metals, and 12 represent non-metal parts of compounds.
1 The aim of the game is to be the first player to get rid of all your cards.
2 Deal 7 cards each, and place the rest of the cards face down in the middle of the table.
3 The player on the left of the dealer goes first, by placing a pair of cards face up on the table which represent a compound (eg iron oxide, sodium sulphate).
4 The second player should then either:
- place a pair of cards on the table from their own hand which represent a compound OR
- carry out a 'displacement' reaction by swapping a more reactive metal (from their hand) for a less reactive metal that is on the table.
(Note: the reactivity of the metal is shown by the points value on the card - the higher the points, the more reactive the metal.)
5 If you cannot go, you have to pick up a card from the pack.
6 If you think someone has made an incorrect move, you can challenge them.
This could be because the two cards they put down do not show a compound, or because they have got their reactivities wrong. If the challenge is correct, you can give them one of your cards. If the challenge is wrong, they give you one of their cards.
The game ends when:
- one player gets rid of all their cards OR
- all cards from the central pack have been taken, and no player can go.
Players who still have cards in their hand add up their points totals.
If no player has got rid of all their cards, the person with the lowest number of points is the winner.
9Fc5 Displacement reaction cards
oxide
sulphate
chloride
nitrate
9Fc6 Reactivity wordsearch 1
There are 15 metals hidden in the wordsearch grid. The names all go across or down.
1 Sort the metals into three groups - high, medium and low reactivity. Some have been done for you.
2 Choose one colour for each group and show this on your chart.
3 Find the metals on the wordsearch grid.
4 Colour them in the correct colour.
Metals:
lithium
mercury
platinum
tin
High reactivity
Medium reactivity
Low reactivity
Colour code:
S
P
L
U
M
I
N
T
O
V
E
R
G
Z
Y
H
[ literacy, knowlege ]
9Fc7 Reactivity wordsearch 2
Use the clues on this sheet to identify the names of 15 metals. Write the name in the space after the clue and then find these metals on the wordsearch grid.
The number of letters in each word is given at the end of the clue. Some of the clues include the names hidden or jumbled up - look for the metals in the words printed
in italics.
1 Unreactive metal that is preferred by the police? (6) ___________
2 Metal that bursts into flames when it reacts with water. (9) ___________
3 Jewellery metal hidden in a packet of Persil? Very strange! (6) ___________
4 Metal in the middle of the Reactivity Series - or in jumble? (4) ___________
5 Metal that reacts with water, and is needed for healthy teeth and bones. (7) ___________
6 The least reactive metal that you have studied in this Unit. (4) ___________
7 Unreactive metal that is also a liquid. (7) ___________
8 Make a metal element from the symbols for titanium and nitrogen. (3) ___________
9 Metal that burns brightly in oxygen, but does not react with water. (9) ___________
10 Metal that is below half way in the Reactivity Series - but if you read the name differently it sounds as though it's out in front. (4) ___________
11 Precious metal found mixed up in a plum tin. (8) ___________
12 Reactive metal used in street lamps because it gives an orange glow. (6) ___________
13 Metal that is quite high in the reactivity series - although it often seems much lower. (9) ___________
14 Metal which reacts with acids. It sounds as though you might wash your dishes in it. (4) ___________
15 The least reactive metal in Group 1 of the Periodic Table. (7) ___________
[ literacy, knowledge ]
9Fd1 Investigating reactivity 1
- Eye protection - Piece of magnesium (1 cm long)
- Boiling tube - Test tube rack
- Stopclock - Measuring cylinder (10 or 25 cm3)
- Thermometer
1 Measure out 10 cm3 of hydrochloric acid and pour it into the boiling tube.
2 Measure the temperature of the acid, and write it down.
3 Take the piece of magnesium. Drop it into the boiling tube and start timing.
4 Watch what happens to the magnesium and the acid.
5 When the reaction is finished, stop the clock. Note the time.
6 Measure the temperature of the liquid in the tube.
1 What are the names of the two reactants in this experiment?
2 Which one is
a an element?
b a compound?
3 How could you tell that a reaction was taking place?
4 How long did the reaction take?
a Did the liquid get warmer or colder during this reaction?
b What was the temperature change?
9Fd2 Investigating reactivity 2
Magnesium reacts with hydrochloric acid to form magnesium chloride and hydrogen gas. You can tell when the reaction has finished, because all the magnesium metal
has disappeared.
There are a number of things that you could change in this reaction that might affect the way that the magnesium reacts with the acid.
1 Name at least three factors that might affect the reaction.
2 Choose one or two of the factors to investigate. How many different experiments will you try? What are the different values of your chosen factor(s)?
3 How will you measure how well the reaction has gone?
4 Will one test for each experiment be good enough, or will you need to repeat your tests? How will you decide?
5 How will you make sure that the experiment is a fair test?
6 Show your plan to your teacher before doing the experiment.
7 Predict how you think your chosen factor(s) might affect the reaction.
8 Design a results table to show all the information you will need.
9 Draw a graph to show your results.
Considering your results/conclusion
10 Describe what you have found out (this is your conclusion).
11 Say whether your results agree with the predictions that you made.
12 Explain your results using scientific ideas if you can.
13 a Did the results fit a logical pattern, or were there any 'odd' results?
b Can you think of any possible explanations for any odd results?
14 a How accurate do you think your measurements were?
b Was this good enough to allow you to draw a conclusion?
15 a Was it a fair test?
b Could you think of any improvements to the way you did the test?
16 Did other groups do the same experiment as you? Do your results agree with theirs?
17 Are there any extra experiments that would help you be more certain of your conclusion?
9Fd3 Reactive and unreactive metals 1
1 Write the name of the correct metal in the space provided.
Choose your answers from the box.
copper gold iron magnesium sodium
a is used in jewellery because it stays shiny? ________________
b burns with a bright white flame? ________________
c goes rusty? ________________
d is used in coins and slowly goes black in air? ________________
e reacts very quickly with the air before you put it in a flame? ________________
2 a Which two metals in the list are the most reactive?
________________ and ________________
b Which two metals in the list are the least reactive?
3 Unscramble the names of these metals using the clues to help you.
a deal is a metal that is used for roofing because it does not react with air and water
________________
b nit is used for coating cans because it is less reactive than iron ________________
c livers is a metal used for jewellery because it is unreactive ________________
d atoms is up is a metal which is more reactive than sodium ________________
aluminium + oxygen → aluminium oxide
a sodium + oxygen ________________ oxide
b ________________ + oxygen → magnesium oxide
c copper + oxygen → ________________
d calcium ________________ → calcium oxide
e iron + oxygen → ________________ ________________
[ knowledge, literacy ]
9Fd4 Reactive and unreactive metals 2
1 Write the name of:
a an unreactive metal that is used in jewellery
b a metal that reacts very quickly with the air before you put it in a flame
c a metal which burns with a bright white flame
d a metal which reacts slowly with the air and goes rusty
e a metal which is used in coins and slowly goes black in air.
2 Arrange the five metals from question 1 in order, from the most reactive to the least reactive.
3 a Unscramble the names of these metals using the clues to help you:
- nit is used for coating cans because it is less reactive than iron
- livers is a metal used for jewellery because it is unreactive
- atoms is up is a metal which is more reactive than sodium.
b There are three metals mentioned in question 3 a. Put them in order of reactivity, starting with the most reactive.
4 Copy and complete these word equations by writing:
- the name of the product if a reaction takes place
- 'no reaction' if a reaction does not take place.
a sodium + oxygen →
b gold + oxygen →
c copper + oxygen →
d calcium + oxygen →
e iron + oxygen →
9Fd5 Discovering and extracting metals
aluminium A1
Date of discovery: 1828
Extracted by: passing an electric current through molten aluminium oxide (electrolysis)
magnesium Mg
Date of discovery: 1829
Extracted by: passing an electric current through molten magnesium chloride (electrolysis)
calcium Ca
Date of discovery: 1808
Extracted by: passing an electric current through molten calcium chloride (electrolysis)
potassium K
Date of discovery: 1807
Extracted by: passing an electric current through molten potassium chloride (electrolysis)
copper Cu
Date of discovery: known
since ancient times
Extracted by: heating copper ore with charcoal (smelting)
silver Ag
Found as the pure metal
gold Au
sodium Na
Extracted by: passing an electric current through molten sodium chloride (common salt)
iron Fe
Extracted by: heating iron ore with charcoal (smelting)
zinc Zn
Date of discovery:
before 1500
Extracted by: heating zinc ore with charcoal (smelting)
9Fd6 Metal reactivity in action 1
Fact 1:
Ships made of iron sometimes have blocks of magnesium attached to the hull.
Fact 2:
Iron can be galvanised by coating it with zinc. This can protect the iron and stop it rusting.
Fact 3:
Steel cans are sometimes coated with tin. Dented cans can be dangerous because rust can get into the food.
Fact 4:
Although aluminium is more common in the ground than iron, in Victorian times aluminium was a very expensive metal.
Fact 5:
Ancient gold jewellery is often in very good condition when it is discovered.
Fact 6:
The bronze age came before the iron age.
9Fd7 Metal reactivity in action 2
Look at each of the 'Fact cards' on worksheet 9Fd/6.
Each of the 'Reason cards' matches one of the 'Fact cards'.
You could:
- write out each of the facts with the correct reason
- cut out the cards and stick each 'Fact card' next to the correct 'Reason card'.
---------------------------------------------------------------------------------------------------------
Reason A
Zinc is a more reactive metal than iron. The zinc will react first so that the iron
is protected.
Reason B
Tin is less reactive than iron, so rust will not affect the metal can in normal conditions. When the can is dented, the iron can be exposed, and rust can get
into the food.
Reason C
Gold is an unreactive metal. Even after thousands of years it doesn't react with air or water.
Reason D
Aluminium is a reactive metal and it is very difficult to extract it from its compounds without modern technology.
Reason E
Magnesium is a reactive metal. The magnesium block reacts with the water before the iron. When the block has all reacted, it can be replaced before the hull of the ship gets damaged.
Reason F
Bronze is mostly made of copper. Copper is an unreactive metal. It is possible to make bronze by heating some types of rock in a fire. Iron ore has to be heated to a much higher temperature to make iron.
9Fd8 Metal reactivity in action 3
- Look at each of the 'Fact cards' on worksheet 9Fd/6.
- Only six of the 'Reason cards' on this sheet are true - the other six reasons are false.
- Match each of the facts with the correct reason.
- Write, or stick the correct pairs in your book.
Bronze is mostly made of copper. Copper is a more reactive metal than iron. This means that iron melts more easily in a flame and was too difficult to make into tools.
Magnesium reacts with the sea water to produce magnesium oxide, which forms a protective coating on the surface of the iron.
Iron is less reactive than tin. It doesn't matter if tin gets into your food because tin is good for you, but iron is dangerous..
Reason G
Reason H
Reason I
The ancient civilisations wrapped their gold up in plastic bags to protect it from air and water.
Reason J
Tin is less reactive than iron, so rust will not affect the metal can in normal conditions. When the can is dented, the iron can be exposed, and rust can get into the food.
Reason K
Aluminium was a very rare metal until large amounts of it were discovered at the end of the 19th century.
Reason L
Iron is a more reactive metal than zinc, so the zinc coating protects the iron.
9Fd9 Explaining the reactivity of metals
The Reactivity Series is a way of putting metals in order. It describes the way that different metals react. To explain why metals react in different ways, we have to go deeper inside the atom. Scientists used to believe that atoms were the smallest possible particles. Just over 100 years ago, there were some experiments that suggested there were some particles that were even smaller. We now call these particles electrons. They carry the electrical current in a circuit, and are the cause of all chemical reactions.
These days, we believe that the atom has a core (or nucleus) at the centre, with electrons going round it. This model is a bit like the solar system with the planets orbiting the Sun. The nucleus has a positive electrical charge, and the electrons have negative electrical charges. The positive and negative charges attract each other. Each element has a different charge on the nucleus, linked to its position in the Periodic Table. The number of electrons in each atom can also be read off the Periodic Table - for example hydrogen has one, oxygen has eight, and magnesium twelve.
The number of electrons and their distances from the nucleus can affect the reactivity of an element. The more electrons there are in an atom, the larger the atom is likely to be, and this will have an influence on how easily the electrons on the outside of the atom can react. The more easily the electrons can react, the more reactive the metal will be.
Here is some data for Group 1 of the Periodic Table. In this group all the metals are reactive, and the reactivity increases as you go down the group. The atomic radius (radius of an atom) is measured in nanometres (one nanometre = 0.000000001m).
Number of electrons
Atomic radius (nm)
0.157
11
0.191
19
0.235
rubidium
37
0.250
caesium
55
0.272
1 a What name is given to the central part of the atom?
b What electrical charge does it have?
2 a What are the particles that move around the core of the atom called?
b What electrical charge do they have?
3 We know that atoms are electrically neutral overall. What does this tell us about the charge on the core and the charge on the other particles in an atom?
4 Describe one way in which atoms are:
a similar to the solar system
b different from the solar system.
5 a What is the rule for the attraction of electrical charges?
b Will an electron feel a greater force of attraction when it is close to the nucleus, or when it is further away?
6 a Plot a graph of atomic radius (vertical axis) against number of electrons in the atom (horizontal axis).
b Describe the relationship between the number of electrons and atomic radius.
c Describe the relationship between reactivity and atomic radius.
7 Two possible explanations for the reactions of metals are given below.
Explanation A: metals react when some of their outer electrons are given away to other non-metal atoms.
Explanation B: metals react when they take in extra electrons from non-metal atoms.
Which of these explanations best fits the evidence? Explain why.
[ knowledge, literacy, considering ]
9F Summary Sheets
Patterns of reactivity
Metals may react with substances around them in the environment such as air,
water and acids.
Some metals react very easily or quickly. They are reactive. Other metals do not react very easily and are described as unreactive. The most reactive metals are found on the left-hand side of the Periodic Table. Less reactive metals are found in the centre of the Periodic Table.
Some gases are more reactive than others. In the air, oxygen is the most reactive gas. Nitrogen is not very reactive. When metals react with the oxygen in the air they form oxides.
metal + oxygen → metal oxide
The metals that react quickly with air also tend to react with water. When metals react with water they form hydrogen gas and a metal hydroxide.
metal + water → metal hydroxide + hydrogen
The metals that react with water also react very quickly with acids. Some metals that don't react with water do react with acids. When metals react with acids, they produce hydrogen and a salt.
metal + acid → salt + hydrogen
The name of the salt formed depends on the name of the acid:
- sulphuric acid makes sulphates
- nitric acid makes nitrates
- hydrochloric acid makes chlorides.
Reactivity Series
Metals can be arranged in a Reactivity Series. The most reactive metals are placed at the top of the table.
More reactive metals can displace less reactive metals from their compounds. In a displacement reaction, the more reactive metal will form a compound, and the less reactive metal is left on its own as the pure element.
For example, iron is more reactive than copper, so it will displace copper from a compound.
iron + copper chloride → iron chloride + copper
Zinc is more reactive than iron, so iron will not displace zinc from a compound.
iron + zinc chloride → no reaction
You can use displacement reactions to work out the position of a metal in the Reactivity Series. For instance, zinc will displace lead from a compound, so we know that zinc is more reactive than lead.
The Reactivity Series can also be used to predict whether reactions will occur.
The reactivity of metals can be linked to their uses. Metals used for construction need to have a low reactivity, otherwise they will corrode away. Some metals, such as aluminium, have a natural protective oxide layer. Others, such as iron, have to be protected from corrosion, e.g. by painting.
Many low reactivity metals have been known for hundreds or thousands of years. They can be extracted by heating their compounds in a fire.
More reactive metals are extracted by electrolysis. This means that they have
only been discovered in the last two hundred years, since the invention of the
electric battery.
9F Target Sheet
Topic
Targets
Before the unit
I have learned this
I have revised this
9Fa
Know the name of the gas in the air that reacts with metals most easily.
Know that some metals are unreactive in air.
Know the name of the gas that is given off when metals react with water.
Know the names of the compounds that form when metals react with water.
9Fb
Know the name of the gas that is given off when metals react with acids.
Know the names of the salts formed from the three common laboratory acids.
Know how to place metals in order of reactivity based on their chemical properties.
Know how to write word equations for the reactions of metals with air, water and acids.
9Fc
Know about displacement reactions.
Know how to write word equations for displacement reactions of metals.
Know how to use the Reactivity Series to predict whether a displacement reaction will take place.
Know how to use the results of displacement reactions to place metals in order of reactivity.
9Fd
Know the names of metals used to make a variety of different objects.
Know some properties of these metals.
Know some factors that affect the reaction of a metal with acid.
Know how the extraction and discovery of metals links to their reactivity.
9F Word Sheets
Word sheets that include new words from the 'Focus on:' pages are available on the Exploring Science website.
9Fa - Shine On/Stinging in the rain/Fire and water
Word
Pronunciation
Meaning
oxidised
ocks-ee-dysed
When a substance reacts with oxygen to form an oxide.
reactive
A substance that reacts with many other substances, or reacts very easily.
unreactive
A substance that reacts with few other substances, or reacts very slowly or not at all.
9Fb - Acid attack/League tables
corrode
When something (such as stone or metal) reacts with chemicals in the air or water and gets worn away.
ocks-eyed
A compound formed when something reacts with oxygen.
A list of metals which shows them in order of their reactivity, with the most reactive at the top.
sulphates
Compounds containing sulphur and oxygen. They are the type of salt formed when a reaction with sulphuric acid occurs.
salt
A compound made when acids react with metals or bases. Many salts are chlorides, sulphates or nitrates. Common salt is sodium chloride.
9Fc - Knowing your place
bonds
Forces holding particles together.
displace
When one element takes the place of another in a compound - a type of substitution.
displacement reaction
A reaction where one element takes the place of another in a compound.
9Fd - Heavy metal
electrolysis
A process where electricity is used to split compounds apart, normally to produce an element.
properties
Something used to describe how a material behaves and what it is like. Hardness is a property of some solids.