Identification of ions by chemical and spectroscopic means

• What can flame tests be used to identify?

  Metal ions
• What color flame does lithium produce?

  Crimson
• What color flame does sodium produce?

  Yellow
• What color flame does potassium produce?

  Lilac
• What color flame does calcium produce?

  Orange-Red
• What color flame does copper produce?

  Green
• What happens to flame colors when a mixture of ions is tested?

  Some flame colors can be masked and not visible
• What precipitate do aluminium, calcium, and magnesium ions form with NaOH?

  A white precipitate
• Which metal ion's precipitate dissolves when excess NaOH is added?

  Aluminium
• What color precipitate does copper(II) produce?

  Blue
• What color precipitate does iron(II) produce?

  Green
• What color precipitate does iron(III) produce?

  Brown
• What is the equation for the reaction of copper ions with hydroxide ions?

  Cu$^{2+}$ + 2OH$^{-}$ -> Cu(OH)$_{2}$
• How many hydroxide ions are needed for each metal ion charge?

  You need as many OH$^{-}$ ions as the charge on the metal ion
• What happens when NaOH reacts with a metal ion bonded to Na?

  They react to form a compound
• What gas is produced when carbonates react with dilute acids?

  Carbon dioxide (CO₂)
• What indicates the presence of carbon dioxide when bubbled through limewater?

  The limewater goes cloudy
• What is the procedure for testing halides?

  Add dilute nitric acid followed by silver nitrate solution
• What precipitate does chloride produce in halide testing?

  A white precipitate
• What precipitate does bromide produce in halide testing?

  A cream precipitate
• What precipitate does iodide produce in halide testing?

  A yellow precipitate
• What is the procedure for testing sulfates?

  Add dilute hydrochloric acid followed by barium chloride solution
• What indicates the presence of sulfate ions in the sulfate test?

  A white precipitate will form
• What are instrumental methods used for in chemistry?

  To detect and identify elements and compounds
• What are the advantages of instrumental methods compared to chemical tests?

  They are accurate, sensitive, and rapid
• What is flame emission spectroscopy used for?

  To analyze metal ions in solutions
• What happens to the sample in flame emission spectroscopy?

  The sample is put into a flame and the light is analyzed
• What type of output does flame emission spectroscopy produce?

  A line spectrum
• What can be identified using the output from flame emission spectroscopy?

  The metal ions in the solution and their concentrations