Explore Chemical Reactions!
Discover the hidden science happening all around you — from burning and rusting to explosive reactions with metals and acids!
👤 Student Profile
1.0 Physical vs. Chemical Properties
Every substance has two types of properties. Can you tell them apart?
🧊 Physical Properties
Features you can observe without changing the substance into something new.
- 🎨 Appearance & colour
- 🧊 State (solid, liquid, gas)
- 🌡️ Melting & boiling point
- ⚖️ Heavy or light
🔥 Chemical Properties
Features that describe how a substance reacts and changes into new substances.
- ⚗️ How acidic or alkaline it is (pH)
- 💧 How it reacts with water or acids
- 🔥 Combustibility (does it burn?)
- ⚡ How readily it reacts
🎯 Property Sorter Activity
Click each property card to sort it into the correct category!
🧊 Physical Properties
🔥 Chemical Properties
💡 Iron + HCl: Iron's physical property is that it's a grey, heavy solid. Its chemical property is that it reacts with hydrochloric acid (HCl) — which itself has a pH of 2 as its chemical property!
2.0 Chemical Changes
In a chemical change, atoms rearrange to form entirely new substances.
🧊 Physical Change
No new substance is formed. The atoms stay the same. Example: liquid water freezing into ice — it's still H₂O!
🔥 Chemical Change
New substances are formed! Atoms rearrange and bond differently. Example: iron + sulfur → iron sulfide (a brand new compound!)
📝 Key Vocabulary
⚗️ Reactants — the starting substances that react together
✨ Products — the new substances made in the reaction
🔄 Chemical Reaction — a process where atoms rearrange to form new substances
⚗️ Reaction Builder
Watch iron + sulfur react!
IRON
SULFUR
IRON SULFIDE
⚖️ Physical Change vs. Chemical Change
Ice Melting
Physical Change ✗
Same substance (H₂O). Reversible. Atoms don't rearrange.
Paper Burning
Chemical Change ✓
New substances formed. Irreversible. Atoms rearrange!
3.0 Burning (Combustion)
When substances burn, they react with oxygen in the air to form brand-new products.
🪵 Charcoal Burning
Charcoal is mostly carbon. When it burns, it combines with oxygen in the air to produce carbon dioxide gas.
Carbon
Oxygen
Carbon dioxide
✨ Magnesium Burning
Magnesium burns with a brilliant white light. It combines with oxygen to form magnesium oxide — a white powder.
Magnesium
Oxygen
Magnesium oxide
⚗️ Properties Change!
The product (magnesium oxide) has completely different properties to the reactants:
| Magnesium | Oxygen | Mg Oxide | |
| State | solid | gas | solid |
| Appearance | shiny | colourless | white powder |
| Conducts? | ✅ Yes | ❌ No | ❌ No |
| Melting pt. | 651°C | -214°C | 2800°C |
🔒 Safety First! Never look directly at burning magnesium — it burns so brightly it can damage your eyes! Always wear safety glasses and hold tongs at arm's length.
🌍 Real-World Combustion Reactions
Burning
Combustion releases heat & light
Rusting
Iron reacts with oxygen & water
Decay
Organic matter breaks down
4.0 Reactions with Water & Acid
Metals react differently with water and acids. These reactions reveal their chemical properties.
💧 Reactions with Water
Some metals react vigorously with water; others don't react at all.
⚠️ Potassium + Water
Potassium is very reactive — it fizzes violently and releases hydrogen gas, which burns! Must be stored under oil.
🔴 SAFETY: This reaction is teacher demonstration only. Safety glasses + safety screen required!
⚗️ Reactions with Hydrochloric Acid
When magnesium is placed in hydrochloric acid, bubbles appear and a new substance forms.
Reactants: Magnesium + HCl | Products: Magnesium chloride + Hydrogen gas
🔦 Testing for Hydrogen Gas
1️⃣ Collect gas in a test tube over water
2️⃣ Light a wooden splint
3️⃣ Place splint at the mouth of test tube
4️⃣ Hydrogen burns with a SQUEAKY POP! 💥
⚗️ Metal Reactions Quick Reference
| Metal | + Water | + HCl Acid | Hydrogen Gas? |
| Potassium | ✅ Very fast | ✅ Explosively | ✅ Yes |
| Magnesium | 🟡 Slow | ✅ Bubbles fast | ✅ Yes |
| Zinc | 🟡 Very slow | ✅ Bubbles | ✅ Yes |
| Iron | 🔴 Very slow | 🟡 Slow bubbles | ✅ Yes |
| Copper | ❌ No reaction | ❌ No reaction | ❌ No |
✏️ Check Your Understanding
1. What gas is produced when magnesium reacts with hydrochloric acid?
2. Why must potassium be stored under oil?
5.0 Signs of a Chemical Reaction
How can you tell a reaction has happened? Click each sign to explore!
🔍 Evidence Explorer — Click each card!
⚠️ Misconception Alert!
❌ "Bubbles always mean a reaction!"
Boiling water makes bubbles too — but that's just a physical change (state change). No new substance is formed!
✅ The truth:
Bubbles in a chemical reaction indicate gas production — a new gas substance has been made (like hydrogen).
🔄 Reversibility Clue
Physical Change
Usually reversible — ice melts, water freezes again
Chemical Change
Usually difficult to reverse — burnt paper can't become paper again!
✏️ Check Your Understanding
1. A student heats water until it boils and sees bubbles. Is this a chemical reaction? Why?
2. Which of the following is NOT a sign that a chemical reaction has taken place?
💡 Did You Know? Chemical reactions happen inside your body every second — digesting food, breathing, and even thinking all involve chemical changes!
Activity: Reaction Match-Up!
Click a reaction type on the left, then match its correct description on the right.
Reaction / Change
Descriptions
Science Mastery Check
12 Questions · Cambridge 7Cp / 7Cc Curriculum
Experiment Complete!
Your Simple Chemical Reactions results:
Scientific Accuracy