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Lab Results Summary

H₂O Detective Lab

Interactive Water Testing & Treatment Simulation

1

Chemical Tests for Water

Drag samples to test tubes to observe color changes

Cobalt(II) Chloride Test Not Started
Test Area

Drag a sample here to test with cobalt(II) chloride

Cobalt(II) Chloride Paper (Blue)
Distilled Water
Tap Water
Ethanol (Control)
Copper(II) Sulfate Test Not Started
Test Area

Drag a sample here to test with copper(II) sulfate

Copper(II) Sulfate (White)
Distilled Water
Tap Water
Ethanol (Control)

Record Your Observations

Sample Cobalt(II) Chloride Test Copper(II) Sulfate Test Contains Water?
Distilled Water
Tap Water
Ethanol
2

Testing Water Purity

Measure melting and boiling points to determine purity

Melting Point Determination Ready
10°C
2°C
-6°C
-14°C
-22°C
-30°C
--°C

Principle: Pure water melts at 0°C. Impurities lower the melting point.

Expected: Distilled water ≈ 0°C, Tap water < 0°C

Boiling Point Determination Ready
120°C
115°C
110°C
105°C
100°C
95°C
--°C

Principle: Pure water boils at 100°C. Impurities raise the boiling point.

Expected: Distilled water ≈ 100°C, Tap water > 100°C

Record Your Measurements

Water Sample Melting Point (°C) Boiling Point (°C) Purity Assessment
Distilled Water
Tap Water
3

Distilled vs Tap Water

Compare properties to understand why distilled water is used in chemistry

Distilled Water Analysis
Pure Water
Test Results

Click tests above to analyze distilled water

Properties of Distilled Water:

  • Produced by distillation (boiling and condensation)
  • Contains minimal dissolved ions
  • pH close to 7 (neutral)
  • Low electrical conductivity
  • No residue after evaporation
Tap Water Analysis
Contains Impurities
Test Results

Click tests above to analyze tap water

Properties of Tap Water:

  • Comes from municipal water supply
  • Contains dissolved salts (Ca²⁺, Mg²⁺, Cl⁻, etc.)
  • pH may vary (often slightly basic)
  • Higher electrical conductivity
  • Leaves residue after evaporation

Why Use Distilled Water in Chemistry?

Distilled water is preferred in practical chemistry because it contains fewer chemical impurities than tap water. This is important because:

Consistent Reactions

Impurities in tap water can interfere with chemical reactions, affecting results.

Accurate Measurements

Dissolved ions affect pH measurements and other analytical tests.

Avoid Contamination

Mineral deposits from tap water can contaminate glassware and equipment.

Key Insight

In chemistry experiments, we need to control all variables. Using distilled water ensures that any observed effects are due to the chemicals being tested, not impurities in the water.

4

Domestic Water Treatment

Explore how water is purified for domestic use

1. Sedimentation

Large particles settle to the bottom by gravity in settling tanks.

2. Filtration

Water passes through layers of sand and gravel to remove smaller particles.

3. Carbon Treatment

Activated carbon removes tastes, odors, and organic impurities by adsorption.

4. Chlorination

Chlorine is added to kill harmful microbes (pathogens) and make water safe to drink.

Build Your Own Water Treatment Model
Filtration Column

Water Treatment Summary

The domestic water supply undergoes several treatment stages to ensure it's safe for drinking:

Stage Process Purpose
Sedimentation Letting water stand in tanks Remove large solid particles by gravity
Filtration Passing through sand/gravel beds Remove smaller suspended particles
Carbon Treatment Using activated carbon Remove tastes, odors, organic impurities
Chlorination Adding chlorine compounds Kill harmful microbes (pathogens)