3.3.1 Tests for ions

• Qualitative analysis identifies components without requiring precise measurements
• Potassium (K+) is essential for nerve and muscle function
• Identifying common cations and anions is crucial for qualitative analysis.


  True
• What flame color does potassium (K+) produce in a flame test?

  Lilac
• Precipitation reactions form an insoluble salt
• Which anion is not useful for precipitation tests because it forms few insoluble salts?

  Nitrate (NO3-)
• What gas is released when sulfate (SO4^2-) is heated with carbon?

  SO2
• What gas is released when a carbonate (CO3^2-) is treated with acid in a gas test?

  CO2
• Heating sulfate (SO4^2-) with carbon releases SO2 gas, which has a rotten egg smell.


  True
• Match the anion with its gas test observation:

  Carbonate (CO3^2-) ↔️ Effervescence, CO2 gas

  Sulfate (SO4^2-) ↔️ Rotten egg smell of SO2

  Nitrate (NO3-) ↔️ Brown/red-brown NO2 gas
• Qualitative analysis measures the precise amounts of each component in a substance.

  False
• The flame color for sodium (Na+) is yellow
• Precipitation reactions occur when two aqueous solutions are mixed and an insoluble salt is formed.


  True
• Sulfate (SO4^2-) forms a white precipitate when it reacts with barium
• What flame color is observed for potassium (K+) in a flame test?

  Lilac
• What is the purpose of qualitative analysis in chemistry?

  Identify components of a substance
• Sodium (Na+) is a common cation found in table salt.

  True
• Match the common anion with its source:

  Chloride (Cl-) ↔️ Table salt

  Sulfate (SO4^2-) ↔️ Fertilizers

  Carbonate (CO3^2-) ↔️ Baking soda

  Nitrate (NO3-) ↔️ Explosives
• Sodium (Na+) produces a yellow flame color in flame tests
• Copper (Cu2+) ions produce a green-blue flame color in flame tests.


  True
• Match the anion with the metal ion it forms an insoluble salt with:

  Chloride (Cl-) ↔️ Silver (AgCl)

  Sulfate (SO4^2-) ↔️ Barium (BaSO4)

  Carbonate (CO3^2-) ↔️ Calcium (CaCO3)
• Carbonate (CO3^2-) releases CO2 gas when treated with acid
• Heating nitrate (NO3-) with copper turnings releases brown/red-brown NO2 gas.

  True
• When carbonate (CO3^2-) is treated with acid, the gas released causes effervescence and turns limewater milky
• What color is the NO2 gas released when nitrate (NO3-) is heated with copper turnings?

  Brown/red-brown
• Qualitative analysis is used to identify what elements or compounds are present in a substance, rather than measuring how much
• What type of measurement is taken in quantitative analysis?

  Precise measurements
• Match the cation with its flame color:

  Potassium (K+) ↔️ Lilac

  Calcium (Ca2+) ↔️ Orange-red

  Copper (Cu2+) ↔️ Green-blue
• What color is the precipitate formed when chloride (Cl-) reacts with silver ions?

  White
• When carbonate (CO3^2-) is treated with acid, CO2 gas is released, which turns limewater milky.


  True