Lesson 4 of 5 · Lab Skills
Experiment⭐ 30 XPTesting for Ions
Lab Skills.
🎯 Your mission
Set it up. Test it. Be amazed.
⚡ The twist
Nature loves to surprise the careful watcher.
Mind = Blown
🔬 The more you look, the more nature shows you.
Make a hypothesis first
Before you start: write down what you think will happen, and why.
What You'll Learn
Flame tests identify metal ions by colour: lithium red, sodium yellow, potassium lilac, calcium orange-red, copper green. Sodium hydroxide gives coloured precipitates for transition metals, and silver nitrate distinguishes the halides by precipitate colour.
Key Words
Tap a word to see its definition.
Materials Needed
- nichrome wire
- concentrated hydrochloric acid for cleaning
- metal salt samples
- Bunsen burner
- sodium hydroxide solution
- silver nitrate solution
Safety First
- Clean the wire in acid between tests — an uncleaned wire gives a false sodium yellow every time.
- Concentrated acid is corrosive and silver nitrate stains and irritates: goggles and gloves throughout, teacher supervision required.
Steps
Read the explanation above and note the two key terms before you start.
Carry out flame tests on five known metal salts using a clean nichrome wire, then on an unknown. Follow with sodium hydroxide and silver nitrate tests and identify the unknown from your combined evidence.
Record what actually happened, including anything that did not match what you expected.
Write a conclusion that answers the question this lesson opened with, and state your uncertainty.
Check Your Understanding
Question 1
1 of 2A lilac flame test result indicates:
Where you see this in real life
This shows up in your everyday life more than you'd think.
Stretch Challenge
Try this in real life this week.
Try one experiment in real life this week — even a tiny one.
For the dinner table
“What's the most surprising thing you learned today?”
Next Smart Experiment
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Testing for Ions
Set it up. Test it. Be amazed.
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