Flame Tests & Metal Hydroxides Flashcards
what does the flame test identify
the flame test identifies metal ions
what colour is the flame when burning Calcium ( CA2+ )
Orange/red flame
what colour is the flame when burning sodium ( NA+ )
Yellow Flame
what colour is the flame when burning Copper ( CU2+ )
Blue/Green flame
what colour is the flame when burning Lilac ( K+ )
Lilac Flame
what colour is the flame when burning Lithium ( Li+ )
Crimson flame
Describe the flame test practical in 4 steps
1) Clean a nichrome wire loop by dipping it completely in a dilute hydrochloric acid
2) Dip the wire into the sample to be tested
3) Hold the wire loop in the blue flame of a bunsen
4) record the colour of the bunsen flame
what does copper ions ( CU2+ ) form when reacted with the sodium hydroxide solution and what’s the equation
copper ions form the blue percipitate copper (II) hydroxide
Equation: Cu2+(aq) + 2OH-(aq) → Cu(OH)2(s)
what does iron (III) ions ( Fe3+ ) form when reacted with the sodium hydroxide solution and what’s the equation
Iron ions form the brown precipitate iron (III) hydroxide
Equation: Fe3+(aq) + 3OH-(aq) → Fe(OH)3(s)
what does iron (II) ions ( Fe2+ ) form when reacted with the sodium hydroxide solution and what’s the equation
iron ions form the green precipitate iron (II) hydroxide
Equation: Fe2+(aq) + 20H-(aq) → Fe(OH)2(s)
what do ammonium ions ( NH4+ ) form when reacted with the sodium hydroxide solution and what’s the equation
the ammonium ions form water and ammonia. ammonia gas evolves out of the solution
Equation: NH4+(aq) + OH-(aq) → NH3(g) + H2O(l)
iron(II) ions + hydroxide ions make what?
Iron(II) hydroxide
What are the correct colours for the following precipitates
1) Iron (III) Hydroxide
2) Copper (II) Hydroxide
3) Iron (II) Hydroxide
Iron (III) Hydroxide = Brown
Copper (II) Hydroxide = Blue
Iron (II) Hydroxide = Green
In flame tests, what piece of apparatus is used to transfer the sample to the Bunsen flame?
Nichrome wire loop
