# Step-by-Step Tutor Guide Let's solve each together, step by step! --- ## **Equations Provided** 1. NH₄Cr₂O₄ → Cr₂O₃ + N₂ + H₂O 2. FeCl₂ + Fe₂O₃ → FeCl₃ + O₂ 3. S²⁻ + Na₂Cr₂O₇ + H₂O → S + NO₂ + Cr(OH)₂ + NaOH 4. LiOH + MgCl₂ → LiCl + Mg(OH)₂ --- ## **a) Are there any noticeable errors in the equations? (2 marks)** Let's check each equation for errors (balancing, chemical logic): ### **Equation 1:** NH₄Cr₂O₄ → Cr₂O₃ + N₂ + H₂O - **Check:** Let's balance N, H, Cr, O. - NH₄Cr₂O₄ contains NH₄⁺ and Cr₂O₄²⁻. Decomposition commonly gives N₂, H₂O, and Cr₂O₃. - **Possible issue:** Check balancing—let's write atoms on both sides: - **N:** 1×NH₄ = 1 N (as NH₄), but produces N₂ (2 N atoms). - **Cr:** 2 Cr both sides. - **O:** 4 O (left); Cr₂O₃ (3), H₂O (1). - **H:** 4 H (left), 2 H (right). - **Conclusion:** Equation is **not balanced**! ### **Equation 2:** FeCl₂ + Fe₂O₃ → FeCl₃ + O₂ - **Check:** - Fe: 1 + 2 = 3 (left), 1 (right). - Cl: 2 (left), 3 (right). - O: 3 (left), 2 (right). - **Conclusion:** **Not balanced**. ### **Equation 3:** S²⁻ + Na₂Cr₂O₇ + H₂O → S + NO₂ + Cr(OH)₂ + NaOH - **Check:** - Where does NO₂ come from? No N on the left. - **Conclusion:** **NO₂ should not be a product**. Likely a typo. ### **Equation 4:** LiOH + MgCl₂ → LiCl + Mg(OH)₂ - **Check:** - Li: 1 (left), 1 (right). - OH: 1 (left), 2 (right). - Mg: 1 (left), 1 (right). - Cl: 2 (left), 1 (right). - **Conclusion:** **Not balanced**. ### **Summary Table** | Equation | Error? | Description | |----------|--------|-----------------------------------------------| | 1 | Yes | Not balanced (N and H mismatch) | | 2 | Yes | Not balanced (all elements mismatched) | | 3 | Yes | NO₂ product impossible (no N on reactant side)| | 4 | Yes | Not balanced (OH and Cl mismatch) | --- ## **b) Name the anions from equation 3. (3 marks)** From equation 3 (left side): S²⁻, Na₂Cr₂O₇, H₂O - **Anions:** 1. **Sulfide** (S²⁻) 2. **Dichromate** (Cr₂O₇²⁻, from Na₂Cr₂O₇) 3. **Hydroxide** (OH⁻, from H₂O, possibly after reaction) --- ## **c) Select an anion from equation 1, pair it with a group 10 metal cation with +3 charge, write formula and IUPAC name. (2 marks)** - **From equation 1:** Anion is Cr₂O₄²⁻ (**chromate**). - **Group 10 metals:** Nickel (Ni), Palladium (Pd), Platinum (Pt). - **Required oxidation state:** +3 (e.g., Ni³⁺). - **Compound:** Ni₂(Cr₂O₄)₃ **IUPAC name:** Nickel(III) chromate --- ## **d) Name the products of equation 2. (2 marks)** Equation 2: FeCl₂ + Fe₂O₃ → FeCl₃ + O₂ - **FeCl₃:** Iron(III) chloride - **O₂:** Oxygen gas --- ## **e) Write complete ionic and net ionic equation for equation 4. (5 marks)** **Equation 4:** LiOH + MgCl₂ → LiCl + Mg(OH)₂ ### **Step 1: Write the complete ionic equation** - LiOH (aq) → Li⁺ (aq) + OH⁻ (aq) - MgCl₂ (aq) → Mg²⁺ (aq) + 2Cl⁻ (aq) - LiCl (aq) → Li⁺ (aq) + Cl⁻ (aq) - Mg(OH)₂ (s) is **insoluble (precipitate)** **Complete ionic equation:** Li⁺ (aq) + OH⁻ (aq) + Mg²⁺ (aq) + 2Cl⁻ (aq) → Li⁺ (aq) + Cl⁻ (aq) + Mg(OH)₂ (s) ### **Step 2: Cancel spectator ions (Li⁺ and Cl⁻)** **Net ionic equation:** Mg²⁺ (aq) + 2OH⁻ (aq) → Mg(OH)₂ (s) --- ## **Summary Table** | Part | Answer | |------|--------| | a | Yes, all equations have errors (balancing or products) | | b | Anions: Sulfide (S²⁻), Dichromate (Cr₂O₇²⁻), Hydroxide (OH⁻) | | c | Ni₂(Cr₂O₄)₃, Nickel(III) chromate | | d | Iron(III) chloride, Oxygen gas | | e | Complete ionic: Li⁺ + OH⁻ + Mg²⁺ + 2Cl⁻ → Li⁺ + Cl⁻ + Mg(OH)₂; Net ionic: Mg²⁺ + 2OH⁻ → Mg(OH)₂ | --- If you need any steps explained in more detail, let me know!