Investigate the reaction between iron and sulfur and practise modelling chemical changes in this lesson plan with activities for 11–14 year olds
In this activity, models are used to describe chemicals and chemical reactions. Students work in groups to investigate iron and sulfur.
This provides an opportunity for students to:
- Reinforce and build upon ideas of elements, mixtures and compounds.
- Investigate the reaction between two elements to make a compound.
- Describe a chemical change using the particle model.
The session combines well-established practical work with the use of the particle model to explain what is happening. Students begin by looking at the properties of iron, sulfur and a mixture of the two. They draw particle diagrams to represent the elements. Three-dimensional models might be shown as well.
The reaction between iron and sulfur is demonstrated and the product is examined. Students are told the product iron sulfide consists of equal numbers of iron and sulfur atoms chemically joined (combined). They are asked to model the change in a role play.
Students will be able to:
- Distinguish between elements, compounds and mixtures.
- Relate formulae to the numbers and types of atom in a compounds.
Sequence of activities
Display samples of iron, sulfur and a mixture of iron and sulfur. Describe iron and sulfur as elements, and the other sample as a mixture.
Give each student a copy of the ’Elements, compounds or mixtures?’ sheet, and ask them to:
- Work in pairs.
- Explain what they think the words element, compound and mixture mean.
Share the learning objectives with students.
Examining the samples
Tell the students that, working in pairs, they are going to examine the samples of iron, sulfur and the mixture using a magnifying glass, a magnet, warming and dilute sulfuric acid. (If available, show the difference in brittleness of iron and sulfur.)
Hand out copies of the ’Comparing iron, sulfur and a mixture of the two’ sheet, and ask pairs of students to:
- Record their observations using the table provided.
- Sketch diagrams of the arrangement of particles in the three samples, on a mini whiteboard.
Invite or choose pairs to show and explain their drawings. Ask other students to comment. Spend time discussing the merits of the drawings and allow pairs time to modify their sketches on the white-boards.
Finally, ask students to copy their final drawings onto the table provided.
Lead a class discussion on the nature of the particles, aiming to draw out the ideas:
- All stuff is made of atoms.
- Pure substances made from just one type of atom are called elements.
- Each element is represented by a symbol, eg Fe for iron and S for sulfur.
Experiment or demonstration
Either demonstrate the effect of strongly heating iron and sulfur together or supervise pairs of students as they carry out the experiment ‘Iron and sulfur reaction’.
Ask students to examine the product and compare its properties with those of the elements and the mixture.
Rearrange students into groups of 3–4. Ask them to:
- Devise a role play activity that would involve the whole class acting out the reaction between iron and sulfur.
- Describe what they would do.
Invite the class to vote on the one they think is the best – and then act it out.
Draw the session(s) to an end by leading a class discussion about the nature of the particles. Reinforce that:
- Pure substances made up of different kinds of atoms chemically joined together are called compounds.
- Particles in a compound are identical, each made up of the same set of atoms.
- The formulae of a compound shows the type and numbers of atoms in its particles, eg FeS.
Write up a word equation and a symbol equation to conclude the discussion. Ask students to look at what they wrote on ‘Elements, compounds or mixtures?’ and to make any changes in light of the session.
Take in the sheets and give written feedback that will support the individual student.
An interesting opening to the session, with a brief self diagnosis, will encourage attentiveness at the outset.
Collaboration between students, comments about particle arrangement and the simple vote on the role-play means that they are evaluating each other’s work throughout the session.
The importance of this topic demands that the student sheets are scrutinised carefully. Written guidance to help each individual is essential.
- Samples of iron, sulfur (FLAMMABLE) and a mixture of iron and sulfur
Health, safety and technical notes
- Read our standard health and safety guidance.
- It is the responsibility of the teacher to carry out an appropriate risk assessment.
- Bunsen flame
- Sulfur (FLAMMABLE)
- Iron powder (POTENTIAL IRRITANT)
- Dilute sulfuric acid (IRRITANT)
Download the activities
Elements, compounds or mixtures?
Comparing iron, sulfur and a mixture of the two
Iron and sulfur reaction
The ’Iron and sulfur reaction’ experiment – including kit list, safety instructions and a video – is available online.
- Editable handout | Word, Size 68 kb
- Handout | PDF, Size 38.24 kb
- Editable handout | Word, Size 77.5 kb
- Handout | PDF, Size 50.22 kb
This lesson plan was originally part of the Assessment for Learning website, published in 2008.
Assessment for Learning is an effective way of actively involving students in their learning. Each session plan comes with suggestions about how to organise activities and worksheets that may be used with students.
K. Hutchings, Classic chemistry experiments. London: Royal Society of Chemistry, 2000.