UNIT 6324: SAMPLE ACTIVITY 3 SAMPLE ASSESSMENT ACTIVITIES AND SCHEDULES 6.15 6324 CHEMISTRY LEVEL 1 WHAT S THE SOLUTION? This activity assesses: Unit: 6324 Identify simple chemical species in solution (Level 1). Element: 2 Carry out a procedure to identify cations and anions present in solutions. CONDITIONS: Individual practical, although solutions and equipment may be shared. The procedure and solutions are to be provided. INSTRUCTIONS: Task A You are required to identify both the cation and the anion in each of the provided solutions A and B. You may use the given flow charts. For each solution, you are required to: 1. Record what you do and your observations. 2. Use your observations to identify the ions present. 2.1 2.2 ASSESSMENT ACTIVITY: WHAT S THE SOLUTION? PAGE 1/4
6.16 SAMPLE ASSESSMENT ACTIVITIES AND SCHEDULES UNIT 6324: SAMPLE ACTIVITY 3 Solution A Cation (positive ion) Solution A Anion (negative ion) Solution B Cation (positive ion) Solution B Anion (negative ion) ASSESSMENT ACTIVITY: WHAT S THE SOLUTION? PAGE 2/4
UNIT 6324: SAMPLE ACTIVITY 3 SAMPLE ASSESSMENT ACTIVITIES AND SCHEDULES 6.17 Identifying Cations Add 2 drops of dilute NaOH solution no precipitate NH 4 +, Na + Add more NaOH solution, heat and test gas produced with red litmus litmus stays red Na + litmus goes blue NH 4 + forms Al 3+, Zn 2+, Pb 2+, Mg 2+ Add excess NaOH solution precipitate remains Mg 2+ precipitate dissolves Al 3+, Zn 2+, Pb 2+ new sample Add 2 drops, then excess NH 3 solution green precipitate forms Fe 2+ forms Al 3+, Pb 2+ forms and dissolves Zn 2+ new sample Add dilute H 2 SO 4 solution. orange precipitate forms Fe 3+ colourless solution Pb 2+ blue precipitate forms Cu 2+ new sample Add 2 drops, then excess NH 3 solution blue precipitate then deep blue solution Cu 2+ brown precipitate forms Ag + new sample Add 2 drops, then excess NH 3 solution brown precipitate then colourless solution Ag + ASSESSMENT ACTIVITY: WHAT S THE SOLUTION? PAGE 3/4
6.18 SAMPLE ASSESSMENT ACTIVITIES AND SCHEDULES UNIT 6324: SAMPLE ACTIVITY 3 Identifying anions bubbles of gas CO 3 2- Add red litmus litmus goes blue OH -, CO 3 2- Add dilute HCI solution no bubbles OH - litmus remains red SO 4 2-, Cl -, I -, NO 3 - Add Ba(NO 3 ) 2 SO 4 2- no precipitate new sample Add AgNO 3 solution precipitate Add dilute NH 3 Cl -, I - solution precipitate disappears Cl - precipitate remains I - no precipitate NO 3 - ASSESSMENT ACTIVITY: WHAT S THE SOLUTION? PAGE 4/4
UNIT 6324: SAMPLE ACTIVITY 3 SAMPLE ASSESSMENT ACTIVITIES AND SCHEDULES 6.19 Assessment Schedule: What s the solution? Unit Standard 6324 Task Number Element and Performance Criteria Evidence (The answers or performance expected from the students) Judgement (A statement that defines the standard to be achieved) A 2.1 1. Observations are recorded. Three observations correct and consistent with solubility rules. 2.2 2. Ions are correctly identified. Three ions correct. Teacher s Notes Suggestions for solutions for A and B include aluminium chloride, aluminium sulfate, ammonium chloride, copper sulfate, iron (III) nitrate, iron (II) sulfate, magnesium chloride, sodium carbonate, zinc sulfate. Laboratory Chemicals Required 2 mol L -1 HCI solution 0.1 mol L -1 BaCl 2 solution red litmus 2 mol L -1 NaOH solution 1 mol L -1 H 2 SO 4 2 mol L -1 NH 3 solution 0.05 mol L -1 AgNO 3 solution ASSESSMENT SCHEDULE: WHAT S THE SOLUTION? PAGE 1/1
6.20 SAMPLE ASSESSMENT ACTIVITIES AND SCHEDULES UNIT 6324: SAMPLE ACTIVITY 3