Chemistry worksheet on writing balanced chemical equations from word descriptions.

To solve these problems, we need to translate the word equations into chemical formulas and then balance them.

1. aqueous sodium chloride reacts with aqueous lead (II) nitrate to yield a lead (II) chloride precipitate and aqueous sodium nitrate
* Reactants: Sodium chloride is NaCl (aq). Lead (II) nitrate involves Pb²⁺ and NO₃⁻, so it is Pb(NO₃)₂ (aq).
* Products: Lead (II) chloride involves Pb²⁺ and Cl⁻, so it is PbCl₂. Since it's a precipitate, it's solid (s). Sodium nitrate is NaNO₃ (aq).
* Unbalanced Equation: NaCl + Pb(NO₃)₂ → PbCl₂ + NaNO₃
* Balancing: There are 2 nitrates on the left, so we need 2 NaNO₃ on the right. That gives us 2 sodiums, so we need 2 NaCl on the left. This also gives us 2 chlorines, which matches the PbCl₂.
* Balanced Equation: 2NaCl(aq) + Pb(NO₃)₂(aq) → PbCl₂(s) + 2NaNO₃(aq)

2. aqueous barium nitrate reacts with sulfuric acid [H₂SO₄(aq)] to yield a barium sulfate precipitate and nitric acid [HNO₃(aq)]
* Reactants: Barium nitrate involves Ba²⁺ and NO₃⁻, so it is Ba(NO₃)₂ (aq). Sulfuric acid is H₂SO₄ (aq).
* Products: Barium sulfate involves Ba²⁺ and SO₄²⁻, so it is BaSO₄. It is a precipitate (s). Nitric acid is HNO₃ (aq).
* Unbalanced Equation: Ba(NO₃)₂ + H₂SO₄ → BaSO₄ + HNO₃
* Balancing: We have 2 nitrates and 2 hydrogens on the left. We need 2 HNO₃ on the right. Everything else balances (1 Ba, 1 SO₄).
* Balanced Equation: Ba(NO₃)₂(aq) + H₂SO₄(aq) → BaSO₄(s) + 2HNO₃(aq)

3. silver nitrate reacts in solution with potassium chromate to yield a silver chromate precipitate and soluble potassium nitrate
* Reactants: Silver nitrate is AgNO₃ (aq). Potassium chromate involves K⁺ and CrO₄²⁻, so it is K₂CrO₄ (aq).
* Products: Silver chromate involves Ag⁺ and CrO₄²⁻, so it is Ag₂CrO₄. It is a precipitate (s). Potassium nitrate is KNO₃ (aq).
* Unbalanced Equation: AgNO₃ + K₂CrO₄ → Ag₂CrO₄ + KNO₃
* Balancing: We have 2 silvers on the right, so we need 2 AgNO₃ on the left. This gives us 2 nitrates and 2 potassiums. We need 2 KNO₃ on the right to match. The chromate balances.
* Balanced Equation: 2AgNO₃(aq) + K₂CrO₄(aq) → Ag₂CrO₄(s) + 2KNO₃(aq)

4. solid calcium carbonate reacts with hydrochloric acid [HCl(aq)] to yield aqueous calcium chloride, carbon dioxide gas, and liquid water
* Reactants: Calcium carbonate is CaCO₃ (s). Hydrochloric acid is HCl (aq).
* Products: Calcium chloride involves Ca²⁺ and Cl⁻, so it is CaCl₂ (aq). Carbon dioxide is CO₂ (g). Water is H₂O (l).
* Unbalanced Equation: CaCO₃ + HCl → CaCl₂ + CO₂ + H₂O
* Balancing: We have 2 chlorines on the right, so we need 2 HCl on the left. This gives us 2 hydrogens, which matches the H₂O. The calcium and carbonate parts balance automatically.
* Balanced Equation: CaCO₃(s) + 2HCl(aq) → CaCl₂(aq) + CO₂(g) + H₂O(l)

5. aqueous zinc chloride reacts with dihydrogen monosulfide gas to yield a zinc sulfide precipitate and hydrochloric acid
* Reactants: Zinc chloride involves Zn²⁺ and Cl⁻, so it is ZnCl₂ (aq). Dihydrogen monosulfide is another name for hydrogen sulfide, H₂S (g).
* Products: Zinc sulfide involves Zn²⁺ and S²⁻, so it is ZnS (s). Hydrochloric acid is HCl (aq).
* Unbalanced Equation: ZnCl₂ + H₂S → ZnS + HCl
* Balancing: We have 2 chlorines and 2 hydrogens on the left. We need 2 HCl on the right. The zinc and sulfur balance.
* Balanced Equation: ZnCl₂(aq) + H₂S(g) → ZnS(s) + 2HCl(aq)

6. magnesium nitrate reacts in solution with potassium hydroxide to yield a magnesium hydroxide precipitate and soluble potassium nitrate
* Reactants: Magnesium nitrate involves Mg²⁺ and NO₃⁻, so it is Mg(NO₃)₂ (aq). Potassium hydroxide is KOH (aq).
* Products: Magnesium hydroxide involves Mg²⁺ and OH⁻, so it is Mg(OH)₂. It is a precipitate (s). Potassium nitrate is KNO₃ (aq).
* Unbalanced Equation: Mg(NO₃)₂ + KOH → Mg(OH)₂ + KNO₃
* Balancing: We have 2 nitrates on the left, so we need 2 KNO₃ on the right. This gives us 2 potassiums, so we need 2 KOH on the left. This also gives us 2 hydroxides, which matches the Mg(OH)₂.
* Balanced Equation: Mg(NO₃)₂(aq) + 2KOH(aq) → Mg(OH)₂(s) + 2KNO₃(aq)

Final Answer:
1. 2NaCl(aq) + Pb(NO₃)₂(aq) → PbCl₂(s) + 2NaNO₃(aq)
2. Ba(NO₃)₂(aq) + H₂SO₄(aq) → BaSO₄(s) + 2HNO₃(aq)
3. 2AgNO₃(aq) + K₂CrO₄(aq) → Ag₂CrO₄(s) + 2KNO₃(aq)
4. CaCO₃(s) + 2HCl(aq) → CaCl₂(aq) + CO₂(g) + H₂O(l)
5. ZnCl₂(aq) + H₂S(g) → ZnS(s) + 2HCl(aq)
6. Mg(NO₃)₂(aq) + 2KOH(aq) → Mg(OH)₂(s) + 2KNO₃(aq)