Acids & Carbonates
Year 9 🧪 Acids, Bases & Salts Write equations for acid + carbonate reactions; test for CO₂.
🫧 Acid + Carbonate
Acids react with carbonates to produce a salt, water and carbon dioxide.
General Equation
$$\text{acid} + \text{carbonate} \rightarrow \text{salt} + \text{water} + \text{CO}_2$$
$$\text{CaCO}_3 + 2\text{HCl} \rightarrow \text{CaCl}_2 + \text{H}_2\text{O} + \text{CO}_2$$🔬 Test for CO₂
Bubble gas through limewater (Ca(OH)₂). It turns milky/cloudy: Ca(OH)₂ + CO₂ → CaCO₃↓ + H₂O
If excess CO₂ added, precipitate redissolves: CaCO₃ + H₂O + CO₂ → Ca(HCO₃)₂ (colourless)
🧮 Mole Calculations
Example: Mass of CO₂ from 10 g CaCO₃ (Mr=100) + excess HCl?
n(CaCO₃) = 10/100 = 0.1 mol
CaCO₃ : CO₂ = 1:1 → n(CO₂) = 0.1 mol
m(CO₂) = 0.1 × 44 = 4.4 g
n(CaCO₃) = 10/100 = 0.1 mol
CaCO₃ : CO₂ = 1:1 → n(CO₂) = 0.1 mol
m(CO₂) = 0.1 × 44 = 4.4 g
Ready to test yourself? Click the Quiz tab above to practise questions on this topic!
Interactive Demonstration — Acids & Carbonates
Carbonates react with acids to produce CO₂ gas.
🫧 Carbonate Reaction Calculator
Calculate mass of CO₂ produced from carbonate + acid.