1.6.1 Qualitative Analysis

• Quantitative analysis measures the amount or concentration of a substance.


  True
• Flame tests identify metal ions based on the color they produce when heated in a flame
• Flame tests are used to identify metal ions based on their flame color.


  True
• Potassium ions (K⁺) produce a lilac or violet flame color.


  True
• Strontium ions (Sr²⁺) produce a white precipitate of SrCO₃.


  True
• Qualitative analysis measures the concentration of substances.

  False
• Qualitative analysis uses measurements to determine precise quantities.

  False
• What do solubility tests determine about a substance?

  Whether it dissolves
• Which group I metal produces a lilac-colored flame?

  Potassium
• Magnesium ions form a white precipitate in group II metal tests.
• Iron(II) ions form a green precipitate in precipitation reactions.
• Sulfate ions form a white precipitate with barium chloride.
• Flame tests are used to identify metal ions based on flame color.
• What is the solubility of silver (Ag⁺) in water?

  Insoluble
• Qualitative analysis measures how much of a substance is present.

  False
• Order the steps of a flame test in qualitative analysis:

  1️⃣ Prepare a sample

  2️⃣ Dip a wire loop into the sample

  3️⃣ Heat the loop in a flame

  4️⃣ Observe the characteristic color
• What happens to magnesium sulfate in water during a solubility test?

  It dissolves
• Order the flame colors of group I metals from longest to shortest wavelength:

  1️⃣ Red (Lithium)

  2️⃣ Orange/Yellow (Sodium)

  3️⃣ Lilac/Violet (Potassium)
• Match the group II metal cation with its corresponding precipitate:

  Magnesium (Mg²⁺) ↔️ White precipitate of Mg(OH)₂

  Calcium (Ca²⁺) ↔️ White precipitate of CaCO₃
• Which anion forms a white precipitate with silver nitrate?

  Chloride (Cl⁻)
• What are the common anions identified in anion tests?

  Chloride, sulfate, carbonate
• The reaction for testing chloride ions is: Cl⁻(aq) + AgNO₃(aq) → AgCl(s) + NO₃⁻(aq)
• The reaction for testing carbonate ions is: CO₃²⁻(aq) + 2HCl(aq) → CO₂(g) + H₂O(l) + 2Cl⁻(aq)
• Sodium ions (Na⁺) produce an orange or yellow flame color in a flame
• What factors affect the solubility of a cation in a solvent?

  Charge, size, hydration energy
• What precipitate forms when silver nitrate reacts with chloride ions?

  Silver chloride
• Qualitative analysis identifies what is present
• Precipitation reactions involve forming an insoluble solid to detect ions.


  True
• Precipitation reactions form an insoluble precipitate
• Magnesium ions (Mg²⁺) form a white precipitate of Mg(OH)₂ in precipitation tests
• Qualitative analysis identifies the chemical composition
• Qualitative analysis identifies what is present
• What is the purpose of flame tests in qualitative analysis?

  Identify metal ions
• Chromatography separates components based on their movement rates.


  True
• Group II metal cation tests involve precipitation reactions.


  True
• Iron ions produce a green flame color in flame tests.

  False
• Anion tests identify the presence of specific anions in a sample.


  True
• Flame tests rely on the release of energy as light when electrons return to their ground state.


  True
• Which metal ion produces a red flame color?

  Lithium
• Magnesium ions are soluble in water but insoluble in NaOH.