Chemical Changes and Reactions — Question 3

(a) Heat

CuCO₃ (s) $\xrightarrow{\Delta}$ CuO (s) + CO₂ ↑ (g)

(b) Light

2AgNO₃ $\xrightarrow{\text{sunlight}}$ 2Ag + 2NO₂ ↑ + O₂ ↑

(c) Electricity

2NaCl $\xrightarrow{\text{electricity}}$ 2Na + Cl₂ ↑

(d) Close contact

Pb(NO₃)₂ (s) + 2KI (s) ⟶ 2KNO₃ + PbI₂ (s)

(e) Solution

NaCl (aq.) + AgNO₃ (aq.) ⟶ AgCl (white ppt.) ↓ + NaNO₃ (aq.)

(f) Pressure

N₂ + 3H₂ $\xrightleftharpoons{\text{above 200 atm}}$ 2NH₃ ↑

(g) Catalyst

2H₂O₂ $\xrightarrow{\text{MnO}_2}$ 2H₂O + O₂ ↑