Chemical Properties & Atomic Model Explorer

🎯 Science Learning Objectives Target Outcome

Mastering Chemical Properties & Atomic Reactions

LO1

Physical vs Chemical

Explain differences in changes of state and identify reaction indicators (color, gas, heat, irreversibility).

LO2

Dalton's Atomic Theory

Use atomic models to demonstrate mass conservation & fixed ratios in CO vs CO₂.

LO3

Chemical Formulas

Analyze subscript numbers to calculate atom counts in H₂O, CO₂, SO₂, NH₃, O₂, and CH₄.

📖 Theory Notes • LO 1: Physical vs Chemical Changes

How to Identify Chemical Reactions

🧊 1. Physical Change

No new substance is formed. The chemical identity remains identical; only state (solid, liquid, gas) or shape changes.

Example: Ice melting into water (H₂O → H₂O). Reversible!

🔥 2. Chemical Change (Reaction)

New substances with new chemical properties are created! Atoms rearrange. Chemical properties include flammability and reactivity with acids.

Example: Burning paper into ash, or limestone reacting with acid.

4 Key Indicators of a Chemical Reaction:

🎨 1. Color Change Substance color changes permanently.

🫧 2. Gas Formation Bubbles or fizzing observed.

⚡ 3. Energy Release Heat, flames, or light emitted.

🔄 4. Irreversible Extremely difficult to reverse back.

Select Virtual Experiment

🔥 EXPERIMENT A: FLAMMABILITY TEST (PAPER) Ready to Ignite

Temp & Energy: 25°C (Room Temp)

Observed Reaction Indicators

✓ Color Change

✓ Gas / Bubble Formation

✓ Energy / Heat Release

✓ Irreversible Reaction

Question: Based on the visual observation above, classify this experiment:

🎮 Practice Quiz: Classifying Changes in Matter

Select the correct classification for each everyday occurrence below!

Score: 0/4

📖 Theory Notes • LO 2: Dalton's Atomic Theory & Mass Conservation

John Dalton's Atomic Model & Definite Proportions

1 Indivisible Atoms

All matter is composed of tiny, indivisible spheres called atoms.

2 Identical Elements

Atoms of the same element are identical in mass and properties.

3 Mass Conservation

Atoms cannot be created or destroyed, only rearranged in reactions.

4 Fixed Integer Ratios

Elements combine in simple whole-number ratios (e.g., CO is 1:1, CO₂ is 1:2).

⚙️ Reaction Simulator

Controls

Select Target Compound:

Molecule Quantity ($n$): 1 Molecule

1x 2x 3x 4x 5x

In Carbon Monoxide (CO), each carbon atom binds with exactly 1 oxygen atom.

Atomic Mass Reference (u):

C Carbon = 12 u

O Oxygen = 16 u

LAW OF CONSERVATION OF MASS BALANCE

✓ Perfect Balance: Mass ΔM = 0 u

🧪 Reactant Atoms

Total Reactants: 28 u

Rearranges

✨ Product Molecules

Total Products: 28 u

Carbon Atom Count

1 = 1

✓ Conserved

Oxygen Atom Count

1 = 1

✓ Conserved

Mass Balance Equality

28 u = 28 u

✓ Zero Mass Lost

📖 Theory Notes • LO 3: Reading & Writing Chemical Formulas

Understanding Chemical Formulas & Subscripts

How Subscripts Work: Water (H₂O)

Subscript 2 after H = 2 Hydrogen atoms.
No subscript after O = 1 Oxygen atom.
Ratio H : O = 2 : 1 (Total = 3 atoms in 1 molecule).

Compound vs Element Molecules

Compound Molecule: Consists of 2 or more different types of elements (CO₂, NH₃, SO₂).
Element Molecule: Consists of atoms of the same element (O₂, N₂).

Select Molecule for Visualization

2D BALL-AND-STICK MODEL

Ratio H : O = 2 : 1

🎯 Student Mastery Diagnostic Quiz

Score: 0 / 3

Question 1 of 3