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Chapter 4

Diversity of Matter Using Separation Techniques

Five techniques, and one decision that picks between them. Seven lessons, seven labs, a chapter map, and thirty questions.

The one idea behind the whole chapter

Chapter 3 told you that the constituents of a mixture keep their own physical properties. This chapter turns that into a tool: if two substances differ in some property, that difference is a handle you can grab to pull them apart.

Every question in this chapter is really this question Which property is different? — and then the technique follows automatically.

Magnetic or not → magnet. Different particle sizes → filtration. A dissolved solid you want → evaporation. A liquid you want → distillation. Different solubilities → chromatography.

You will only ever be asked to memorise five techniques. What earns the marks is choosing the right one, in the right order, and saying why.

This is scoped for G3. The reverse-osmosis detail the textbook marks optional for G2 is core here — and it is exactly the part Section 4.3 is built on.

4.1–4.2 · Choosing a technique

Lesson 1

Why separate, and how to choose

The decision that runs the whole chapter — plus a planner where you separate real mixtures step by step.

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The five techniques

Lesson 2

Magnetic attraction

Iron filings from sulfur, and iron from scrap metal in a Singapore scrapyard.

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Lesson 3

Filtration

Residue and filtrate, pores and particle sizes — and the one mixture filtration cannot touch.

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Lesson 4

Evaporation

Getting the dissolved solid back. Salt pans, dried ikan bilis, and what you lose.

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Lesson 5

Distillation

Boiling and condensation. The distillate, the water cycle, and the solar still.

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Lesson 6

Chromatography

Substances that dissolve to different extents. Watch an ink spot separate into four.

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4.3 · Putting it to work

Lesson 7

Potable water in Singapore

The Four National Taps, NEWater's three steps, desalination — and why we use reverse osmosis rather than distillation.

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Revise and practise

Revision

The whole chapter on one page

Every definition, the decision table, all five techniques with their applications, and the water facts.

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Practice

30 interactive questions

Label the apparatus, sort the techniques, plan a multi-step separation — every wrong answer explains itself.

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Challenging · Lvl 2

Challenging Qns Lvl 2

Twenty harder questions with the options set deliberately close together — only correct reasoning separates them.

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