Pure Substance vs Mixtures Worksheet
11 • Pure Substance vs Mixtures
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Date:
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Pure Substance: Made of only one type of particle throughout. Fixed properties; cannot be separated physically.
Mixture: Made of two or more different substances physically mixed. Retain separate properties; can be separated physically.
Warm-Up: The Disappearing Sugar Mystery
Engage
You stir white sugar into hot tea until you can no longer see the crystals. A friend claims: "The sugar vanished and turned into liquid tea, so it is now a pure substance." Do you agree or disagree? What actually happened to the sugar particles?
Zoomed-In Particle View: 8 Chambers
Select Pure Substance or Mixture and note particle evidence
Chamber A 5 Units
Pure Substance Mixture
Evidence:
Chamber B 5 Units
Pure Substance Mixture
Evidence:
Chamber C 6 Units
Pure Substance Mixture
Evidence:
Chamber D 5 Units
Pure Substance Mixture
Evidence:
Chamber E 5 Units
Pure Substance Mixture
Evidence:
Chamber F 6 Units
Pure Substance Mixture
Evidence:
Chamber G 5 Units
Pure Substance Mixture
Evidence:
Chamber H 5 Units
Pure Substance Mixture
Evidence:
Practice: Real-World Classification Matrix
Classify sample and describe atomic particles
| Sample | Formula | Classification | Particle-Level Description |
|---|
| Distilled Water | \(H_2O\) | | |
| Pure Substance Mixture | | | |
| |
| Salt Water | \(NaCl + H_2O\) |
Pure Substance Mixture
| |
| Pure Oxygen | \(O_2\) |
Pure Substance Mixture
| |
| Clean Inhaled Air | \(N_2, O_2, Ar, CO_2\) |
Pure Substance Mixture
| |
| Baking Soda | \(NaHCO_3\) |
Pure Substance Mixture
| |
| 24-Karat Gold Ring | \(Au\) |
Pure Substance Mixture
| |
Particle Sketch: Draw a Pure Substance & a Mixture
Draw at least 6 particles in each box
1. Pure Substance Model Every single particle must be identical
2. Mixture Model Must include 2 or more distinct particle types
10-Station Lab Rotation: Classifying Matter
Rotate through the 10 stations. Record your macroscopic observations and classify using particle-level evidence.
| Station | Sample Observed | What You See With Your Eyes | Classification | Particle-Level Reason |
|---|
| 1 | | | | |
| Pure Substance Mixture | | | | |
| |
| 2 | | |
Pure Substance Mixture
| |
| 3 | | |
Pure Substance Mixture
| |
| 4 | | |
Pure Substance Mixture
| |
| 5 | | |
Pure Substance Mixture
| |
| 6 | | |
Pure Substance Mixture
| |
| 7 | | |
Pure Substance Mixture
| |
| 8 | | |
Pure Substance Mixture
| |
| 9 | | |
Pure Substance Mixture
| |
| 10 | | |
Pure Substance Mixture
| |
1. Which station sample was the trickiest to classify as a mixture or pure substance just by looking with your naked eyes? Explain why.
2. Choose one station that was a mixture. What physical method (e.g. magnet, filtration, evaporation) could you use to separate it?
3. When you examine matter at the particle level, what is the single rule that tells you it is a pure substance and not a mixture?
Rapid-Fire Particle Concept Check
Quick Review
1. When salt water boils, what rises into the air as steam?
Only water particles (the salt remains in the pot) Both water and salt particles rise together
2. In a mixture, can you change the recipe amounts?
Yes, you can mix substances in any proportion No, mixtures always have a fixed chemical recipe
3. If a container holds a pure substance, what is true?
Every single particle unit is identical throughout There are different types of unbonded particles inside
4. Why can a magnet separate iron filings from sand?
Iron retains its magnetic physical property in the mix The magnet chemically dissolves the sand
Station Rotation Slides
Station 1
Iron Filings
Lab Rotation 1 of 10
Sample Composition
What is inside this material?
- 100% Pure Iron Metal (Symbol: \(Fe\))
- Tiny shredded magnetic shavings
- No other substances or fillers added
Record on your sheet: Is this a Pure Substance or a Mixture? What is your particle reason?
Dark gray, metallic magnetic shavings in dish
Station 2
Garden Dirt (Soil)
Lab Rotation 2 of 10
Sample Composition
What is inside this material?
- Sand and silt mineral grains
- Decomposed leaves and roots (humus)
- Clay bits, tiny pebbles, and moisture
Record on your sheet: Is this a Pure Substance or a Mixture? What is your particle reason?
Brown soil with visible pebbles, sand, and plant bits
Station 3
Copper Wire
Lab Rotation 3 of 10
Sample Composition
What is inside this material?
- 100% Pure Copper Metal (Symbol: \(Cu\))
- Drawn into a flexible electrical wire
- No other metals or alloys mixed in
Record on your sheet: Is this a Pure Substance or a Mixture? What is your particle reason?
Shiny, reddish-orange solid metallic wire coil
Station 4
Kool-Aid Drink
Lab Rotation 4 of 10
Sample Composition
What is inside this material?
- Water (\(H_2O\)) solvent
- Dissolved white sugar (\(C_{12}H_{22}O_{11}\))
- Citric acid, flavoring, and red food dye
Record on your sheet: Is this a Pure Substance or a Mixture? What is your particle reason?
Clear red liquid with powdered drink mix dissolved in water
Station 5
Table Salt
Lab Rotation 5 of 10
Sample Composition
What is inside this material?
- 100% Sodium Chloride (Formula: \(NaCl\))
- Strict 1-to-1 ratio of sodium to chlorine
- Uniform white cubic crystal grains throughout
Record on your sheet: Is this a Pure Substance or a Mixture? What is your particle reason?
Pure white, cubic crystalline grains in dish
Station 6
