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Basic 4 · Science · Materials

Liquid–Liquid Mixtures

In this topic you will identify liquid–liquid mixtures and tell mixtures that mix well from those that do not.

By the end of these notes you should be able to:

  • Explain what a liquid–liquid mixture is
  • Identify miscible and immiscible liquids
  • Give everyday examples

What you already know

  • Solid–solid mixtures (Basic 2)

Copy everything that has a blue line on its left into your notebook. The other parts are for reading.

Strand
Diversity of matter
Sub-strand
Materials
Indicator
B4.1.2.2.1 – Identify a liquid-liquid mixture and describe how to separate its components

Introduction

Pour palm oil into water. The oil floats on top and does not mix. Pour lime juice into water. They mix completely. Both are liquid–liquid mixtures.

1. Liquid–Liquid Mixtures

Liquid–liquid mixture: A mixture of two or more liquids.

2. Miscible and Immiscible Liquids

Two kinds
KindMeaningExamples
misciblemix completely; you cannot see two layerswater and lime juice; water and vinegar
immiscibledo not mix; they form layerswater and palm oil; water and kerosene
Two clear jars: one with water and lime juice mixed, one with water and palm oil in two layers
Figure 1: Miscible and immiscible liquids Draw the two jars and label them.Illustration: Sirbus

3. Why Oil Floats

Palm oil is lighter (less dense) than water, so it floats on top.

Safety: Never taste or smell kerosene. Keep it away from fire.

New words

mixture
Two or more substances mixed together.
miscible
Able to mix completely.
immiscible
Not able to mix.
layer
A level of one substance lying on another.
dense
Heavy for its size.
float
To stay on top of a liquid.

Summary

  • A liquid–liquid mixture contains two or more liquids.
  • Miscible liquids mix completely.
  • Immiscible liquids form separate layers.
  • Palm oil floats on water because it is less dense.

Class activity: Mix Test

  1. Pour water and palm oil into a clear cup. Observe.
  2. Pour water and lime juice into another cup. Observe.
  3. Record which is miscible and which is immiscible.

You need: Water, Palm oil, Clear plastic bottles, Metal spoon

Exercises

Answer in your exercise book first, then check your answers.

  1. 1. Which pair is immiscible?

    • A. Water and palm oil
    • B. Water and lime juice
    • C. Water and vinegar
    • D. Water and sugar syrup
    Show answer
    Answer: Water and palm oilThey form layers.

  2. 2. Liquids that mix completely are…

    • A. Miscible
    • B. Immiscible
    • C. Solid
    • D. Dense
    Show answer
    Answer: MiscibleThey form one layer.

  3. 3. Why does oil float on water?

    • A. It is less dense
    • B. It is heavier
    • C. It is colder
    • D. It is solid
    Show answer
    Answer: It is less denseLighter liquids float.

  4. 4. Water and vinegar are miscible.

    • A. True
    • B. False
    Show answer
    Answer: TrueThey mix completely.

  5. 5. Kerosene and water mix completely.

    • A. True
    • B. False
    Show answer
    Answer: FalseThey form layers.

  6. 6. A level of one substance on another is a ______.

    Show answer
    Answer: layerImmiscible liquids form layers.

  7. 7. Give one example each of miscible and immiscible liquids.

    Show answer
    Answer: E.g. water and lime juice; water and palm oil.They behave differently.

  8. 8. How could you tell if two clear liquids are miscible?

    Show answer
    Answer: Mix them and look for separate layers; if there is only one layer, they are miscible.Observe for layers.

Homework

  1. Mix a little cooking oil and water in a cup at home. Draw what you see.