🤔
Whenever something changes into something completely different, a chemical reaction has happened!
🍳
🌟 Simple Analogy
Breaking an egg is a physical change — you still have egg. But cooking it in a pan? You can never "uncook" it! That's a chemical reaction.
Look for at least ONE of these 4 clues 👇
🌡️
The mixture gets hotter or colder — energy is released or absorbed.
Eg: Quick lime + water — it gets very hot!
🎨
A completely new colour appears — a new substance has formed!
Eg: Iron nail in copper sulphate turns brownish-red.
💨
You see bubbles or smell something — a gas is being released.
Eg: Zinc + acid → fizzing hydrogen gas bubbles.
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🧊
A solid precipitate forms in solution, or a solid dissolves away.
Eg: Lead nitrate + potassium iodide → yellow solid.
✍️
A chemical equation is a shorthand recipe — it tells you what goes in and what comes out!
🍕
🌟 Think of it like a recipe!
Dough + Tomato Sauce + Cheese → Pizza
Ingredients on the left = reactants. Pizza on the right = product. The arrow means "becomes".
🔤 Magnesium burning in air
← REACTANTS (what we start with) PRODUCT (what we end up with) →
🔬 NOT balanced yet!
⚠️ Problem: 2 oxygen atoms on left, only 1 on right — NOT balanced!
✅ Balanced with state symbols
✅ 2 Mg = 2 Mg ✓ | 2 O = 2 O ✓ Perfect!
⚖️
Balancing is like making sure a seesaw is even — same number of atoms on both sides!
⚖️
🌟 The Golden Rule
Atoms are never created or destroyed (Law of Conservation of Mass). Only add coefficients (numbers in front) — never change the formula!
| Atom | Left (Reactants) | Right (Products) | Balanced? |
|---|---|---|---|
| Fe | 1 | 3 | ✗ No |
| H | 2 | 2 | ✓ Yes |
| O | 1 | 4 | ✗ No |
Fe + 4H₂O → Fe₃O₄ + H₂
Fe + 4H₂O → Fe₃O₄ + 4H₂
3Fe + 4H₂O → Fe₃O₄ + 4H₂
3Fe(s) + 4H₂O(g) → Fe₃O₄(s) + 4H₂(g)
🗂️
Think of these as 5 "personalities". Learn the story behind each one!
🔥
Some reactions release heat, others absorb heat.
💡
🌟 Memory Trick
EXOthermic = Energy EXits (goes OUT) → surroundings get HOT 🔥
ENDOthermic = Energy ENters the reaction (goes IN) → surroundings get COLD ❄️
🔥
❄️
Our body breaks down glucose with oxygen, releasing the energy we need to move and stay warm.
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy — this keeps our body at 37°C!
🔄
Always happen together — like two sides of the same coin!
🎁
🌟 Gift Analogy
Oxygen is a gift. The substance that gives away oxygen is REDUCED (it lost something). The substance that receives oxygen is OXIDISED (it gained something).
+
→
+
Oxidation Is Loss (of H, or gain of O) | Reduction Is Gain (of H, or loss of O)
In every redox reaction both happen simultaneously — you can't have one without the other!
🌍
Oxidation isn't just in the lab — it affects your food, your bike, and your home!
🦺
Metals react with moisture and oxygen over time. Iron forms reddish-brown rust, silver turns black, copper turns green.
Iron + Water + O₂ → Iron Oxide (rust)
🍟
Fats and oils react with oxygen from the air, changing the smell and taste. That's why chips left out taste different!
Fat/Oil + O₂ → Rancid compounds
🧠
Use these clever tricks when writing your answers.
🤝
Two things come together and become ONE. A + B get married and become AB!
💥
One thing breaks apart. AB can't stay together and splits into A + B!
💪
Stronger element kicks out the weaker one. Iron is stronger than copper!
💃
Two partners swap. AB + CD → AD + CB. The first halves swap over.
🔥
Energy EXITs — heat goes out into surroundings. Vessel feels HOT.
🧊
Energy ENTERs — absorbed from surroundings. Vessel feels COLD.
Click the correct answer. Can you get all 4 right? 🏆
📋
Save this for quick revision before your exam!
🤝
A + B → AB
Things join together
💥
AB → A + B
One thing breaks apart
👊
A + BC → AC + B
Stronger kicks weaker out
🔄
AB + CD → AD + CB
Two pairs swap partners
⚡
Oxidation + Reduction
Always happen together
A balanced equation must have the same number of atoms of each element on both sides. Add coefficients only — never change subscripts. This is because matter is never created or destroyed in a chemical reaction!
🧪 Chemical Reactions & Equations · Grade 10 Science · Chapter 1
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