Separation Technique Flashcards
What is fractional distillation used for?
“Separating a mixture of miscible liquids into its component parts or fractions.”
How are fractions separated in fractional distillation?
“By their boiling points.”
What is the order of distillation?
“Fractions distil over in ascending order of their boiling points
What is the required difference in boiling points for efficient fractional distillation?
“More than 10°C.”
What is the main difference between the apparatus for fractional distillation and simple distillation?
“A fractionating column is introduced between the distillation flask and the condenser.”
What is the role of the fractionating column?
“It is packed with glass beads and does the actual separation.”
How does the temperature vary within the fractionating column?
“The upper part of the column is at a lower temperature than the lower part.”
Which vapors pass to the condenser?
“Only the vapor with the same temperature as the upper part of the fractionating column (the fraction with the lowest boiling point).”
What happens to vapors with higher boiling points?
“They condense as they enter the upper part of the fractionating column and flow back into the distillation flask.”
What happens after the fraction with the lowest boiling point is distilled over?
“The temperature in the upper part of the column rises until the boiling point of the next fraction is reached
What are some natural products recovered from crude oil by fractional distillation?
“Petrol
What are the two main parts of a fractional distillation plant?
“The boiler (where the crude oil is kept boiling) and the fractionating tower (where the actual separation takes place).”
Where do fractions with lower boiling points emerge in the fractionating tower?
“Near the top part of the tower.”
Where do fractions with higher boiling points emerge in the fractionating tower?
“Near the lower part of the tower.”
What is chromatography used for?
“To separate a mixture of solutes.”
How does chromatography work?
“It uses a solvent moving over a porous
What kind of substances can be separated using chromatography?
“Coloured as well as colourless substances
What is a common method of chromatography?
“Ascending paper chromatography.”
What is a separating funnel used for?
“To separate two immiscible liquids.”
What are immiscible liquids?
“Liquids that do not mix together to form a single liquid
How does a separating funnel work?
“The lower
Give an example of liquids that can be separated using a separating funnel.
“Petrol and water.”
What is the key difference between evaporation and distillation?
“Evaporation recovers a solid solute from a solution
When is crystallization preferred over evaporation?
“When the solute is a salt that decomposes easily on heating.”