02. Balancing equations

ATL

• Communication skills: Use and interpret a range of discipline-specific terms and symbols.

1. Deduce how these examples should be correctly balanced:

a PbO(s) → Pb(s) + O₂(g)

b H₂(g) + Cl₂(g) → HCl(g)

c SO₂(g) + O₂(g) → SO₃(g)

d AgNO₃(aq) + Cu(s) → Cu(NO₃)₂(aq) + Ag(s)

e MgO(s) + HNO₃(aq) → Mg(NO₃)₂(aq) + H₂O(l)

f CH₄(g) + O₂(g) → CO₂(g) + H₂O(l)

g C₈H₁₈(l) + O₂(g) → CO₂(g) + H₂O(l)

h N₂(g) + 3H₂(g) → NH₃(g)

i H₂S(g) + I₂(aq) → HI(aq) + S(s)

j Al(s) + HCl(aq) → AlCl₃(aq) + H₂(g)

k CaCO₃(s) + HCl(aq) → CaCl₂(aq) + H₂O(l) + CO₂(g)

2. Find correct formulas and state symbols, and then balance the equations for the word equations shown:

a oxygen + hydrogen → water

b aluminium + bromine → aluminium bromide

c nitrogen + oxygen → dinitrogen pentoxide

d dinitrogen monoxide → nitrogen + oxygen

3. Formulate balanced chemical equations for the precipitation reactions of the activity in lesson 01. The formulas for the ionic compounds you tested are copper(II) sulfate, CuSO₄; sodium carbonate, Na₂CO₃; lead(II) nitrate, Pb(NO₃)₂; potassium hydroxide, KOH; barium chloride, BaCl₂; and iron(II) sulfate FeSO_4.

4. Deduce how these examples should be correctly balanced:

a H₃BO₃(aq) → H₄B₆O₁₁(aq) + H₂O(l)

b P₂I₄(s) + P₄(s) + H₂O(l) → PH₄I(s) + H₃PO₄(aq)

c AsCl₃(aq) + NaBH₄(aq) → AsH₃(g) + NaCl(aq) + BCl₃(l)

d Cu(s) + HNO₃(l) → Cu(NO₃)₂(aq) + NO(g) + H₂O(l)

e KIO₃(aq) + KI(aq) + H₂SO₄(aq) → K₂SO₄(aq) + H₂O(l) + I₂(aq)

5. Many of the examples include compounds of phosphorus and arsenic. Identify where phosphorus and arsenic are located on the periodic table. What do the compounds they form suggest about their reactivity and electronegativity?

Assessment opportunity

• In this activity you have practiced skills that are assessed using Criteria A: Knowing and understanding.

Citations:

¹Termaat, Annie. “Chapter 5.” Chemistry for the IB MYP 4 & 5, Hodder Education, London, 2016, pp. 104–105.