Test For Gases

Test for gases

Gases
Ammonia
Colorless, pungent
Turns Red litmus blue

Carbon dioxide
Colorless, Odourless
Gives a white ppt with limewater

Chlorine
Greenish Yellow, pungent
Turns Blue litmus red and then bleaches red litmus

Hydrogen
Colorless, Odourless
Extinguish lighted splint with a pop sound

Oxygen
Colorless, Odourless
Relights glowing splint

Sulphur dioxide
Colorless, Choking
Turns acidified potassium dichromate from orange to green

Nitrogen dioxide
Reddish Brown, pungent
Turns Blue litmus red

Water
Colorless Odourless
Condenses into cold water. Turns White anhydrous copper sulphate turns blue,
Cobalt chloride paper turns blue to pink



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Entry by
Json Lim
http://www.oleveltuition.com/

Purification

Note: Methods of purification are used only on mixtures. You cannot separate hydrogen from water using these methods.
Separation Techniques
Method

Filtration
Remove insoluble substances from liquids

Distillation
Obtain solvent from solute (water from salt water)

Fractional Distillation
Separate a mixture of miscible liquids (petroleum, ethanol and water)

Separating funnel
Separate a mixture of immiscible liquids (oil and water)

Crystallization
Obtain solute from solution (sugar from sugar solution, salts from their own salt solution)

Chromatography
Separate mixtures that contain chemically similar components. Very often used for identification

Crystallization (important for salt making)
Steps to take
• Heat the solution to obtain a saturated solution
• Once saturated, allow the solution to cool
• Crystals of the salt will appear
• Filter the crystals from the solution
• Dry the salt between filter paper
Chromatography (Pure Chemistry only)
• Rf value = distance moved by the spot/distance move by the solvent front. Rf value cannot be more than 1.
Test for purity
• Test for constant melting and boiling point
• Chromatography

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Entry by
Json Lim
http://www.oleveltuition.com/

Equipment to measure volumes

Measurement Equipment
Apparatus
Stopwatches
Seconds, time

Thermometer
Degrees Celsius, temperature

Beaker
Cm3, rough volume up to 250.

Measuring cylinder
Cm3, volume nearest to Cm3

Pipette
Cm3, fixed volume of 5, 10, 20, 25, 50 Cm3

Burette
Cm3, volume nearest o.1 Cm3

Gas syringe
Cm3, volume of gas


Enjoy!
Entry by
Json Lim
http://www.oleveltuition.com/