Currently Empty: $0.00
Lesson 24: Chromatography What is chromatography? Separating inks and dyes Reading chromatograms
Year 8 • Chemistry
Lesson 24: Chromatography
In this lesson, students learn how chromatography is used to separate mixtures, such as inks and dyes, and how to read simple chromatograms to identify different substances.
Lesson Objectives
- Understand what chromatography is.
- Describe how inks and dyes can be separated.
- Explain how chromatography works.
- Read and interpret simple chromatograms.
1. What Is Chromatography?
Chromatography is a method used to separate mixtures into their different substances.
It is often used to separate coloured substances such as inks and food dyes.
[ Image Placeholder – Basic Chromatography Setup ]
Key idea:
• Some substances dissolve and travel at different speeds
• This allows them to separate
• Some substances dissolve and travel at different speeds
• This allows them to separate
2. Separating Inks and Dyes
Many inks and dyes are actually mixtures of different colours.
Chromatography can be used to separate them.
[ Image Placeholder – Ink Separation ]
Steps:
• Draw a pencil line near the bottom of the paper
• Place ink spots on the line
• Put paper in solvent (water)
• Colours move up the paper at different speeds
• Draw a pencil line near the bottom of the paper
• Place ink spots on the line
• Put paper in solvent (water)
• Colours move up the paper at different speeds
Real-life link:
This method is used in forensic science to analyse pen inks.
3. How Chromatography Works
Chromatography works because different substances have different solubilities.
[ Image Placeholder – Solvent Moving Up Paper ]
• More soluble substances travel further
• Less soluble substances travel a shorter distance
• Less soluble substances travel a shorter distance
4. Reading Chromatograms
A chromatogram is the result of a chromatography experiment.
[ Image Placeholder – Example Chromatogram ]
• Each spot represents a different substance
• One spot = pure substance
• Multiple spots = mixture
• One spot = pure substance
• Multiple spots = mixture
Practice Questions
A. Fill in the Blanks
- Chromatography is used to __________ mixtures.
- In chromatography, substances travel at different __________.
- The liquid used is called the __________.
- A chromatogram shows the __________ of chromatography.
- Pencil is used because ink would __________.
B. True or False
- Chromatography can separate inks.
- All substances travel the same distance.
- One spot on a chromatogram means a pure substance.
- Chromatography is only used in school labs.
- Water can be used as a solvent.
C. Short Answer
- What is chromatography?
- Why is pencil used to draw the baseline?
- What does a chromatogram show?
- What does it mean if there are two spots?
- Give one real-life use of chromatography.
✅ Show Answer Key
A. Fill in the Blanks
- separate
- speeds
- solvent
- result
- dissolve
B. True or False
- True
- False
- True
- False
- True
C. Short Answer
- A method to separate mixtures.
- Ink would dissolve and affect results.
- The separated substances.
- The substance is a mixture.
- Forensic ink analysis / food dyes.
© Aviate Learning – Chromatography (Year 8)
🧪 Interactive Chromatography Simulator
Choose an ink, add solvent, and watch how the colours separate as the solvent moves up the paper.
Choose an ink and click “Add Solvent”.