Reacting metals with acids
Aims
In this practical students will:
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react four different metals with an acid to decide which reacts most vigorously
make observations of the reactions to decide how vigorously the reactions are occurring.
Students will be working scientifically to:
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interpret observations and data, including identifying patterns and using observations,
measurements, and data to draw conclusions
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present observations and data using appropriate methods, including tables and graphs
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use appropriate techniques, apparatus, and materials during fieldwork and laboratory work,
paying attention to health and safety.
make and record observations and measurements using a range of methods for different
investigations; and evaluate the reliability of methods and suggest possible improvements
Students will be using the following literacy skills:
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explaining observations in metal–acid reactions and suggesting relative reactivity of different
metals.
Teacher notes
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Students will need to have seen the test for hydrogen using a lit splint before attempting this
practical.
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Students will need to be familiar with what happens when metals react with acids before trying to
answer the questions in this task, and should be aware of how to construct word equations.
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Extending students will be required to construct formula equations for the reactions seen. They
will not be required to work out the formulae for the salts, so these have been provided for them
on the sheet.
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Try and provide similarly sized pieces of all the metals so that students can make fair
comparisons between the reactions they see.
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The skill sheet Recording results is available on Kerboodle to support students with designing a
table for their observations.
© Oxford University Press 2014 www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original.
Answers
Hypothesis
Bubbles/fizzing will be seen, as hydrogen is a gas. Students may go on to state that this gas
would produce a squeaky pop if lit with a splint.
Questions
1 Bubbles/fizzing; temperature change (if the test tube was felt to get hot); the metal disappears
or ‘gets used up’.
2 lead, iron, zinc, and magnesium
The more reactive the metal with the acid, the more it bubbled.
3 Place an empty test tube over the reaction and collect any gas produced. Then hold a lit splint to
the mouth of the upturned tube. If hydrogen gas is present, a squeaky pop will be heard.
4 magnesium + hydrochloric acid → magnesium chloride + hydrogen
zinc + hydrochloric acid → zinc chloride + hydrogen
lead + hydrochloric acid → lead chloride + hydrogen
iron + hydrochloric acid → iron chloride + hydrogen
Extension
1 The heat of the lit splint causes hydrogen to react with oxygen.
hydrogen + oxygen → water
2H2 + O2 → 2H2O
2 A large amount of hydrogen would be highly explosive, and therefore dangerous to ignite.
3 Mg + 2HCl → MgCl2 + H2
Fe + 2HCl → FeCl2 + H2
Zn + 2HCl → ZnCl2 + H2
Pb + 2HCl → PbCl2 + H2
4 Exothermic. Magnesium and hydrochloric acid. Magnesium reacts more vigorously with
hydrochloric acid than zinc. It will release more energy, and hence get hotter, during the
reaction.
Support sheet
The accompanying support sheet is contains a table for students to record their observations.
© Oxford University Press 2014 www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original.
Technician notes
Safety
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Hydrochloric acid is corrosive.
Iron filings can be irritating to eyes. Do not rub your eyes with your hands.
Lead is toxic. Wash hands after handling.
Eye protection should be worn.
Take care when handling test tubes as they can become hot and bubble during the experiment.
Equipment and materials
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eye protection
0.5 M hydrochloric acid (CLEAPSS Hazcard 47A)
pipettes
test tubes
zinc metal pieces
lead metal pieces (CLEAPSS Hazcard 56)
iron filings (CLEAPSS Hazcard 55A)
magnesium ribbon pieces, about 2 cm in length
splints
heatproof mats
test-tube racks
optional: Bunsen burner (for testing for hydrogen gas)
© Oxford University Press 2014 www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original.