Chemistry Revision - Gothic Ballet Edition

⚗️ Chemistry Equations ⚗️

A Gothic Ballet Guide to Acid Reactions

🦇 Magnesium + Nitric Acid 🦇

General Equation to Learn

Metal + Acid → Salt + Hydrogen

Word Equation

Magnesium + Nitric Acid → Magnesium Nitrate + Hydrogen

Balanced Symbol Equation

Mg + 2HNO₃ → Mg(NO₃)₂ + H₂

Full Ionic Equation

Mg(s) + 2H⁺(aq) + 2NO₃⁻(aq) →
Mg²⁺(aq) + 2NO₃⁻(aq) + H₂(g)

Net Ionic Equation

Mg(s) + 2H⁺(aq) → Mg²⁺(aq) + H₂(g)

✨ Enchanted Notes

✨ This is a metal + acid reaction — magnesium displaces hydrogen
✨ Hydrogen gas bubbles off (test with a burning splint — it gives a squeaky pop!)
✨ Magnesium nitrate remains dissolved in the solution

🩰 Spectator ions (NO₃⁻) watch from the wings like dancers waiting their turn — they don't participate in the main performance!

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🦇 Sodium Carbonate + Sulfuric Acid 🦇

General Equation to Learn

Carbonate + Acid → Salt + Water + Carbon Dioxide

Word Equation

Sodium Carbonate + Sulfuric Acid → Sodium Sulfate + Water + Carbon Dioxide

Balanced Symbol Equation

Na₂CO₃ + H₂SO₄ → Na₂SO₄ + H₂O + CO₂

Full Ionic Equation

2Na⁺(aq) + CO₃²⁻(aq) + 2H⁺(aq) + SO₄²⁻(aq) →
2Na⁺(aq) + SO₄²⁻(aq) + H₂O(l) + CO₂(g)

Net Ionic Equation

CO₃²⁻(aq) + 2H⁺(aq) → H₂O(l) + CO₂(g)

✨ Enchanted Notes

✨ This is a carbonate + acid reaction
✨ Products: sodium sulfate (salt), water, and carbon dioxide gas
✨ CO₂ fizzing creates dramatic bubbling — test with limewater (turns milky)
✨ This general pattern works with any carbonate + acid combination

🩰 Spectator ions (Na⁺ and SO₄²⁻) pirouette gracefully but don't change — they remain unchanged throughout the reaction!

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🦇 Copper Oxide + Sulfuric Acid 🦇

General Equation to Learn

Metal Oxide + Acid → Salt + Water

Word Equation

Copper Oxide + Sulfuric Acid → Copper Sulfate + Water

Balanced Symbol Equation

CuO + H₂SO₄ → CuSO₄ + H₂O

Full Ionic Equation

CuO(s) + 2H⁺(aq) + SO₄²⁻(aq) →
Cu²⁺(aq) + SO₄²⁻(aq) + H₂O(l)

Net Ionic Equation

CuO(s) + 2H⁺(aq) → Cu²⁺(aq) + H₂O(l)

✨ Enchanted Notes

✨ Metal oxides are bases — this is a neutralisation reaction
✨ Products: copper sulfate (salt) + water only
✨ Black copper oxide powder dissolves and turns the solution blue
✨ No gas produced — just salt and water

🩰 Spectator ion (SO₄²⁻) remains unchanged — like a vampire watching from the shadows!

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🌙 The Three Sacred Acids to Memorise 🌙

Hydrochloric Acid → makes Chloride salts

HCl

Sulfuric Acid → makes Sulfate salts

H₂SO₄

Nitric Acid → makes Nitrate salts

HNO₃

✨ Enchanted Memory Tips

✨ HCl — Hydrochloric acid (found in your stomach!)
✨ H₂SO₄ — Sulfuric acid (the "king of acids" — notice it has 2 hydrogen atoms)
✨ HNO₃ — Nitric acid (makes nitrate salts)

💜 The name of the salt depends on which acid you use — this is an exam favourite!

🩰 Remember: The H⁺ ions are what make them acidic — they're the lead dancers in every acid reaction!

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Test your knowledge — AQA GCSE Triple Chemistry level

🌙 Practice Questions 🌙

Click each "Reveal Answer" to check your work

Question 1 Word Equations

Write the word equation for the reaction between zinc and hydrochloric acid.

[2 marks]

✦ Answer

Zinc + Hydrochloric Acid → Zinc Chloride + Hydrogen

This follows the general pattern: Metal + Acid → Salt + Hydrogen. Hydrochloric acid always produces chloride salts.

Question 2 Word Equations

Write the word equation for the reaction between calcium carbonate and nitric acid.

[2 marks]

✦ Answer

Calcium Carbonate + Nitric Acid → Calcium Nitrate + Water + Carbon Dioxide

Carbonate + Acid → Salt + Water + CO₂. Nitric acid produces nitrate salts. Don't forget the three products!

Question 3 Symbol Equations

Write the balanced symbol equation for the reaction between magnesium and hydrochloric acid.

[2 marks]

✦ Answer

Mg + 2HCl → MgCl₂ + H₂

You need 2HCl to supply the 2 chloride ions for MgCl₂ and the 2 hydrogen atoms for H₂. Check: 1 Mg, 2 H, 2 Cl on each side ✓

Question 4 Symbol Equations

Write the balanced symbol equation for the reaction between zinc oxide and sulfuric acid.

[2 marks]

✦ Answer

ZnO + H₂SO₄ → ZnSO₄ + H₂O

Metal oxide + Acid → Salt + Water. This is already balanced: 1 Zn, 1 O (from ZnO) + 2 H + 1 S + 4 O (from acid) → 1 Zn + 1 S + 4 O (sulfate) + 2 H + 1 O (water). ✓

Question 5 Balancing

Balance the following equation:

Na + H₂SO₄ → Na₂SO₄ + H₂

[1 mark]

✦ Answer

2Na + H₂SO₄ → Na₂SO₄ + H₂

There are 2 Na on the right in Na₂SO₄, so you need 2Na on the left. H and SO₄ are already balanced.

Question 6 Balancing

Balance the following equation:

Al + HCl → AlCl₃ + H₂

[1 mark]

✦ Answer

2Al + 6HCl → 2AlCl₃ + 3H₂

This one is tricky! Start with Cl: AlCl₃ needs 3 Cl, but H₂ needs even numbers of H. Using 2Al gives 2AlCl₃ (6 Cl), so 6HCl, which gives 6 H = 3H₂. Check: 2 Al, 6 H, 6 Cl each side ✓

Question 7 Ionic Equations

The balanced equation for zinc reacting with sulfuric acid is:

Zn + H₂SO₄ → ZnSO₄ + H₂

Write the net ionic equation for this reaction. Include state symbols.

[3 marks]

✦ Answer

Zn(s) + 2H⁺(aq) → Zn²⁺(aq) + H₂(g)

The SO₄²⁻ ion is a spectator — it appears unchanged on both sides. The net ionic equation removes spectator ions and shows only the species that actually change. Don't forget state symbols: (s) for zinc solid, (aq) for ions in solution, (g) for hydrogen gas.

Question 8 Ionic Equations

Write the full ionic equation for sodium hydroxide reacting with hydrochloric acid.

The balanced equation is: NaOH + HCl → NaCl + H₂O

Then identify the spectator ions and write the net ionic equation.

[4 marks]

✦ Answer

Full ionic: Na⁺(aq) + OH⁻(aq) + H⁺(aq) + Cl⁻(aq) → Na⁺(aq) + Cl⁻(aq) + H₂O(l) Spectator ions: Na⁺ and Cl⁻

Net ionic: OH⁻(aq) + H⁺(aq) → H₂O(l)

This is the classic neutralisation ionic equation — it's the same for ANY alkali + acid reaction. H⁺ from the acid reacts with OH⁻ from the alkali to form water. This is a key equation to memorise!

Question 9 Predicting Products

Predict the products and write the balanced symbol equation for:

Iron oxide (Fe₂O₃) + Hydrochloric acid (HCl)

[3 marks]

✦ Answer

Fe₂O₃ + 6HCl → 2FeCl₃ + 3H₂O

Metal oxide + Acid → Salt + Water. Iron(III) oxide gives iron(III) chloride (FeCl₃). Balancing: 2 Fe needs 2FeCl₃ (6 Cl total → 6HCl). The 3 O from Fe₂O₃ + 6 H from 6HCl gives 3H₂O. Check: 2 Fe, 3 O, 6 H, 6 Cl each side ✓

Question 10 Application

A student adds excess magnesium carbonate to hydrochloric acid in a beaker.

(a) Write the balanced symbol equation for this reaction. [2 marks]

(b) Describe two observations the student would make. [2 marks]

(c) Explain why excess magnesium carbonate is used. [1 mark]

[5 marks total]

✦ Answer

(a) Balanced equation: MgCO₃ + 2HCl → MgCl₂ + H₂O + CO₂ (b) Two observations:
1. Fizzing / effervescence / bubbles of gas produced (CO₂)
2. The solid (magnesium carbonate) dissolves / decreases in size; unreacted solid remains at the bottom when the acid is used up

(c) Excess magnesium carbonate is used to ensure all the acid has reacted / been neutralised. The unreacted solid can then be filtered off to give a pure salt solution.

This is a required practical-style question. The method of using excess solid + filtration is how you make a pure salt from an insoluble reactant — a key AQA topic!

Total marks available: 25 marks

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