C4.2 Tests Flashcards
Carbon dioxide test
- Bubble CO2 through limewater [Ca(OH)2 solution]
= should turn cloudy white (white precipitate of calcium carbonate)
Chlorine test
-Hold a damp piece of blue litmus paper near to container of the substance
= if Cl present –> paper turns RED then WHITE
Hydrogen test
- Place lighted splint near the mouth of the container of gas
= if H2 present should ignite w squeaky pop
Oxygen test
- Place glowing splint near the mouth of the container of gas
= if O2 present, the splint should relight
Flame test
- Dip nichrome wire loop in HCL and burn to decontaminate + rinse w distilled water
- dip again in HCL and then sample
- Burn in ROARING BLUE FLAME, observe flame colour
Flame test colours: Lithium sodium potassium calcium copper
Lithium - red sodium - yellow potassium - lilac calcium - orange red copper - green blue
Hydroxide precipitate test
React few drops of NaOH solution w metal ion solution = note the colour of precipitate
Hydroxide precipitate colours iron(II) iron(III) copper(II) calcium zinc
Iron(II) - green Iron(III) - orange brown Copper(II) - blue Calcium - white Zinc - White
Additional test for calcium and zinc?
React w excess NaOH
- Zinc hydroxide precipitate should redissolve = colourless solution
- Nothing happens to calcium hydroxide precipitate
Sulfate ions
- add few drops of dilute HCL
-React w barium chloride
= white precipitate should form
Carbonate ions
- add few drops of dilute HCL
= should see bubbles of gas (CO2)
can do additional co2 test
Halide ions method
- add few drops of dilute nitric acid
- add few drops of silver nitrate solution
Silver halide precipitate colours:
Chloride - white
Bromide - cream
Iodide - yellow
*has ide endings for the IONS!
How do you analyse a gas chromatogram
Each peak = substance in the mixture
the area under peak = relative amount of each substance
What is a mass spectrometer
can measure masses of atoms + molecules, used to analyse relative amounts of different isotopes of an element + structure of molecules
