Methods of Purification and Analysis
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name the separation method for two solids, one of which is soluble in a suitable solvent
use suitable solvent to dissolve, then filter
name the separation method for insoluble solid + liquid/solution
filtration
name the separation method for solution (solid that decomposes upon heating dissolved in liquid completely)
crystallisation
name the separation method for solution (solid that will not be decomposed upon heating dissolved in liquid completely)
evaporation to dryness
name the separation method for solution (solid that dissolved in liquid completely) to obtain liquid from the solution
simple distillation
name the separation method for two solids, one of which sublimes
sublimation
name the separation method for two immiscible liquids
use of separating funnel
name the separation method for two miscible liquids
fractional distillation
name the separation method for mixture of organic compounds such as coloured dyes and amino acids present in small amounts
paper chromatography
4 substances that sublimes
iodine (I2), ammonium chloride, dry ice (solid CO2), naphthalene
miscible liquids definition
liquids that dissolve in each other completely to form a solution
immiscible liquids definition
liquids that do not mix/cannot dissolve in each other
4 steps to obtain both sand and dry salt from mixture of sand and salt
-Add water to mixture to dissolve salt. -Filter the mixture. -Sand is obtained as residue. -Evaporate the filtrate to dryness to obtain salt.
2 steps to obtain sand and water from mixture of sand and water
-Filter mixture to remove sand as residue. -Water will be obtained as filtrate.
6 steps to obtain copper (II) sulfate crystals and calcium carbonate from mixture of calcium carbonate (insoluble in water) and copper (Ii) sulfate solution
-Filter mixture to remove calcium carbonate as residue. -Evaporate most water from filtrate to obtain a saturated copper(II) sulfate solution. -Cool the hot saturated solution to obtain pure copper(II) sulfate crystals. -Filter the solution to obtain the crystals, -wash the crystals with a little cold distilled water -and dry crystals between pieces of filter paper.
3 steps to obtain both methanol and water from its mixture
-Heat mixture to vaporise the two liquids. -The hot vapour rise and enter the condenser. -The liquid with lower boiling point (methanol) will be distilled first while the one with the higher boiling point (water) will be distilled later.
5 steps to obtain both iodine and sand from its mixture
-Place mixture in an evaporating dish -and place an inverted funnel over the mixture. -Upon gentle heating, all iodine sublimes, -and deposits on the cold filter funnel. -Sand is left in the evaporating dish after the sublimation.
3 steps to obtain both oil and water from its mixture
-Place the mixture in the separating funnel. -The less dense liquid (oil) will be on top of the denser liquid (water). -The 2 liquids can be separated by manipulating the tap.
4 steps to carry out chromatography on food colouring
-A spot of the food colouring is applied to the chromatography paper. -The chromatography paper is dipped in the solvent with the pencil line above the solvent level. -The solvent travels up the paper, carrying the dyes along. -A dye that is more soluble in the solvent will travel further.
relationship between solubility of the dye in solvent and the distance traveled on the chromatography paper
as greater the solubility of the dye in solvent, the greater the distance traveled by it on the chromatography paper
Rf value formulae
distance travelled by the substance _____________________________________ distance travelled by the solvent
when will the Rf value of a substance change
when the chromatography is carried out under different conditions. for example, under different solvents and different temperatures
how to ensure that the Rf value stays the same
carry out chromatography under the same conditions (i.e. same solvent and same temperature.
what all Rf value should be
less than 1