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.”
What do decantation, filtration, and centrifugation have in common?
“They are all used to separate an insoluble solid from a liquid.”
How does filtration separate mixtures?
“Using a porous material like filter paper to separate insoluble particles from liquids.”
How does centrifugation separate mixtures?
“Using a machine that spins test tubes at high speed
What is the difference between distillation and fractional distillation?
“Distillation is used to recover a solvent from a solution. Fractional distillation is used to separate miscible liquids.”
Where is sieving used?
“Mining industries (e.g.
Where is magnetic separation used?
“Steel industry and to remove magnetic impurities from tin ore.”
Give examples of substances purified by sublimation.
“Iodine and ammonium chloride.”
Where is filtration used in industry?
“Water purification plants and breweries.”
How is filtration used in the purification of pipe-borne water?
“Water strains through filter beds to remove suspended material
Where is centrifugation used in hospitals?
“To separate blood cells from plasma in blood samples.”
Where is evaporation used?
“Salt-making industries (e.g.
Where is crystallization used?
“Industries where purity of the product is important
Where is distillation used?
“Gin distilleries and water distilleries (for the manufacture of gin and distilled water respectively).”
Where is fractional distillation used?
“To separate crude oil into its components (e.g.
Is a mixture homogeneous or heterogeneous?
“A mixture can be either homogeneous or heterogeneous.”
Is a compound homogeneous or heterogeneous?
“A compound is always homogeneous.”
Are the constituents of a mixture chemically bound together?
“No
Are the components of a compound chemically bound together?
“Yes
Can the constituents of a mixture be easily separated by physical means?
“Yes
Can the components of a compound be separated by physical means?
“No
Can the constituents of a mixture be added together in any ratio by mass?
“Yes
Are the components of a compound present in a fixed ratio by mass?
“Yes
Are the properties of a mixture the sum of those of its individual constituents?
“Yes
Do the properties of a compound differ from those of its component elements?
“Yes
Define matter.
“Anything that has mass and occupies space. “
Give examples of matter.
“Plants and animals
What are the three physical states of matter?
“Solid
What is an element?
“A substance that cannot be split into simpler units by an ordinary chemical process. “
Give examples of elements.
“Iron
What is a compound?
“A substance which contains two or more elements chemically combined together. “
Give examples of compounds.
“Water
What is a mixture?
“A mixture contains two or more constituents which can easily be separated by physical methods. “
Give examples of mixtures.
“Air
Define a physical change.
“A change that is easily reversed and in which no new substances are formed.”
Give examples of physical changes.
“Changes in the states of matter (e.g.
Define a chemical change.
“A change that is not easily reversed and in which new substances are formed.”
Give examples of chemical changes.
“Burning
In a physical change, are new substances formed?
“No.”
In a chemical change, are new substances formed?
“Yes.”
Is there a change in the mass of a substance involved in a physical change?
“No.”
Is there a change in the mass of a substance that undergoes a chemical change?
“Yes.”
Is there a considerable amount of heat change involved in a physical change?
“Not usually
Is there a considerable amount of heat change usually involved in a chemical change?
“Yes.”
What happens when zinc oxide is heated?
“It turns yellow.”
What happens to the color of zinc oxide when it cools?
“It changes back to its original white color.”
Is the color change of zinc oxide a physical or chemical change?
“Physical.”
Why is the color change of zinc oxide a physical change?
“Because the process is easily reversed without affecting the chemical nature of the substance.”
What happens when magnesium burns?
“It burns with a dazzling white flame and a white ash (magnesium oxide) is obtained.”
What kind of change is the burning of magnesium?
“Chemical.”
What happens when sugar is heated in a crucible?
“It burns to give a black residue (carbon) and water droplets.”
Can the sugar be recovered when the water droplets are added to the black residue?
“No.”
What kind of change is the charring of sugar?
“Chemical.”
What happens when metallic zinc is added to dilute tetraoxosulphate(VI) acid?
“Gas bubbles (hydrogen) are released
What is left behind after complete evaporation of the solution?
“A white residue
What kind of change is the dissolution of zinc in acid?
“Chemical.”
Why are the burning of magnesium, the charring of sugar, and the dissolution of zinc in acid chemical changes?
“Because new products are formed and the original materials cannot be recovered by physical means.”
What is the most abundant element in the Earth’s crust?
“Oxygen (about 47%)”
What is the second most abundant element in the Earth’s crust?
“Silicon (about 28%)”
What are other significant constituents of the Earth’s crust?
“Aluminium (7%)
What is the most abundant gas in the atmosphere?
“Nitrogen (75.5%)”
What is the second most abundant gas in the atmosphere?
“Oxygen (23%)”
What are other constituents of the atmosphere?
“Argon (1.2%) and others (0.3%)”
What is the most abundant ion in seawater?
“Chloride (Cl-) (55%)”
What is the second most abundant ion in seawater?
“Sodium (Na+) (30.6%)”
What are other significant ions in seawater?
“Sulphate (SO4^2-) (7.7%)
What are the component elements of water?
“Hydrogen and oxygen”
What is the formula for water?
“H2O”
What are the component elements of sand?
“Silicon and oxygen”
What is the formula for sand?
“SiO2”
What are the component elements of limestone?
“Calcium
What is the formula for limestone?
“CaCO3”
What are the component elements of common salt?
“Sodium and chlorine”
What is the formula for common salt?
“NaCl”
What are the component elements of sugar (sucrose)?
“Carbon
What is the formula for sugar (sucrose)?
“C12H22O11”
What are the component elements of ethanol?
“Carbon
What is the formula for ethanol?
“C2H5OH”
What are the component elements of washing soda?
“Sodium
What is the formula for washing soda?
“Na2CO3.10H2O”
What are the component elements of hard soap?
“Sodium
What is the formula for hard soap?
“C17H35COONa”
What are the component elements of caustic soda?
“Sodium
What is the formula for caustic soda?
“NaOH”
Is a physical change easily reversible?
“Yes.”
Is a chemical change easily reversible?
“No.”
Are new substances formed in a physical change?
“No.”
Are new substances formed in a chemical change?
“Yes.”
Is there a change in the mass of a substance in a physical change?
“No.”
Is there a change in the mass of a substance in a chemical change?
“Yes.”
Is there a large heat change in a physical change?
“Not usually (except for latent heat changes).”
Is there a large heat change in a chemical change?
“Usually.”
What does sieving separate?
“Solids of different sizes.”
What does magnetic separation separate?
“Magnetic solids from non-magnetic ones.”
What does sublimation separate?
“Solids which sublime
What do decantation, filtration, and centrifugation separate?
“Insoluble solid from a liquid.”
What do evaporation and crystallization separate?
“Soluble solid from a solution.”
What does distillation separate?
“Solvent from its solution.”
What does fractional distillation separate?
“Miscible liquids.”
What does a separating funnel separate?
“Immiscible liquids.”
What does chromatography separate?
“Solutes from a solution.”
Where is sieving used in the food industry?
“To separate gari particles before they are fried.”
Which industries use magnetic separation?
“The steel industry and industries that remove magnetic impurities from tin ore.”
Give two examples of substances that are purified industrially by sublimation.
“Iodine and ammonium chloride.”
Name two industries that use filtration to remove solid particles from liquids.
“Water purification plants and breweries.”
In hospitals, what is centrifugation used for?
“To separate blood cells from plasma.”
Where is evaporation used on the coast of Africa?
“In salt-making industries to obtain salt from seawater.”
In which industries is crystallization used where purity is important?
“Manufacture of drugs and sugar production.”
Name two types of distilleries that use distillation.
“Gin distilleries and water distilleries.”
What is separated by fractional distillation of crude oil?
“Petrol
