tests for cations

• What do flame tests identify?

  Metal ions
• What colour do lithium ions burn?

  crimson
• What colour do sodium ions burn?

  yellow
• What colour do potassium ions burn?

  lilac
• What colour do calcium ions burn?

  orangey-red
• What colour do copper ions burn?

  green
• What equipment is used in a flame test?

  platinum wire loop

  bunsen burner
• How do you clean a platinum wire loop?

  dip in dilute HCL and hold over blue flame until no colour burns
• How do you test metals by forming insoluble hydroxides?

  add a few drops of sodium hydroxide into solution
• What colour precipitate does Calcium, ca2+ form?

  white
• What colour precipitate does Copper(II), Cu2+ form?

  Blue
• What colour precipitate does Iron(II) Fe2+ form?

  Green
• What colour precipitate does Iron(III), Fe2+ form?

  Brown
• What colour precipitate does Aluminium, Al3+ form?

  White, redissolves in excess NaOH to form colourless
• What colour precipitate does magnesium, Mg2+ form?

  White