Experimental Chemisty

Question 1

State the ways to separate solid-solid mixtures.

Answer 1

• Magnetic Attraction
• Sieving
• Using a suitable solvent
• Sublimation

Question 2

State the ways to separate solid-liquid mixtures.

Answer 2

• Filtration
• Evaporation to dryness
• Crystallisation
• Simple distillation

Question 3

State the ways to separate liquid-liquid mixtures.

Answer 3

• Separating Funnel
• Chromatography
• Fractional distillation

Question 4

State the ways to perform crystallisation.

Answer 4

1. Heat the solution (to evaporate most of the water) to obtain a saturated solution
2. Cool the saturated solution to allow the crystals to form
3. Filter the mixture to obtain crystals as residue and diluted solution as filtrate
4. Wash the crytals with cold distilled water to remove impurities
5. Dry crystals between few sheets of filter paper

Question 5

What is used to dry acidic gases?

Answer 5

• ## Concentrated Sulfuric Acid

Question 6

What is used to dry alkaline gases?

Answer 6

• Fused Calcium Chloride (Cannot dry Ammonia)
• Calcium Oxide (Quick Lime)

Question 7

What does impurities do to the m.p and b.p?

Answer 7

• Impurities lower the melting point of a solid and increase the boiling point of a liquid.
• Impurities causes melting and boiling to take place over a range of temperatures