Laboratory rules
(ix) In case of fire, remain calm, switch of the source of fuel-gas tap. Leave the laboratory through the emergency door. Use fire extinguishers near the chemistry laboratory to put of medium fires. Leave strong fires wholly to professional fire fighters.
(x) Do not carry unauthorized item from a chemistry laboratory. Download full notes here
An apparator /apparatus are scientific tools/equipment used in performing scientific experiments. The conventional apparator used in performing scientific experiments is called standard apparator/apparatus. If the conventional standard apparator/apparatus is not available, an improvised apparator/apparatus may be used in performing scientific experiments. An improvised apparator/apparatus is one used in performing a scientific experiment for a standard apparator/apparatus. Most standard apparatus in a school chemistry laboratory are made of glass because:
(i)Glass is transparent and thus reactions /interactions inside are clearly visible from outside
(ii) Glass is comparatively cheaper which reduces cost of equipping the school chemistry laboratory
(iii) Glass is comparatively easy to clean/wash after use.
(iv) Glass is comparatively unreactive to many chemicals.
Apparatus are designed for the purpose they are intended in a school chemistry laboratory:
Apparatus for measuring volume
1. Measuring cylinder
Measuring cylinders are apparatus used to measure volume of liquid/ solutions. They are calibrated/ graduated to measure any volume required to the maximum. Measuring cylinders are named according to the maximum calibrated/graduated volume e.g.
“10ml” measuring cylinder is can hold maximum calibrated/graduated volume of “10mililitres” /“10 cubic centimetres”
“50ml” measuring cylinder is can hold maximum calibrated/graduated volume of “50mililitres” /“50 cubic centimetres”
“250ml” measuring cylinder is can hold maximum calibrated/graduated volume of “250mililitres” /“250 cubic centimetres”
“1000ml” measuring cylinder is can hold maximum calibrated/graduated volume of “1000mililitres” /“1000 cubic centimetres”
2. Burette Chemistry form one full notes
Burette is a long and narrow/thin apparatus used to measure small accurate and exact volumes of a liquid solution. It must be clamped first on a stand before being used. It has a tap to run out the required amount out. They are calibrated/ graduated to run out small volume required to the maximum 50ml/50cm3.
The maximum 50ml/50cm3 calibration/ graduation reading is at the bottom .This ensure the amount run out from a tap below can be determined directly from burette reading before and after during volumetric analysis.
Burettes are expensive and care should be taken when using them.
3. (i) Pipette
Pipette is a long and narrow/thin apparatus that widens at the middle used to measure and transfer small very accurate/exact volumes of a liquid solution.
It is open on either ends.
The maximum 25ml/25cm3 calibration/ graduation mark is a visible ring on one thin end.
To fill a pipette to this mark, the user must suck up a liquid solution upto a level above the mark then adjust to the mark using a finger.
This requires practice.
(ii) Pipette filler
Pipette filler is used to suck in a liquid solution into a pipette instead of using the mouth. It has a suck, adjust and eject button for ensuring the exact volume is attained. This requires practice.
4. Volumetric flask.
A volumetric flask is thin /narrow but widens at the base/bottom. It is used to measure very accurate/exact volumes of a liquid solution.
The maximum calibration / graduation mark is a visible ring.
Volumetric flasks are named according to the maximum calibrated/graduated volume e.g.
“250ml” volumetric flask has a calibrated/graduated mark at exact volume of “250mililitres” /“250centimetres”
“1l” volumetric flask has a calibrated/graduated mark at exact volume of “one litre” /“1000 cubic centimeters”
“2l” volumetric flask has a calibrated/graduated mark at exact volume of “two litres” /“2000 cubic centimeters”
5. Dropper/teat pipette
A dropper/teat pipette is a long thin/narrow glass/rubber apparatus that has a flexible rubber head.
A dropper/teat pipette is used to measure very small amount/ drops of liquid solution by pressing the flexible rubber head. The numbers of drops needed are counted by pressing the rubber gently at a time
(b)Apparatus for measuring mass
1. Beam balance
A beam balance has a pan where a substance of unknown mass is placed. The scales on the opposite end are adjusted to “balance” with the mass of the unknown substance. The mass from a beam balance is in grams.
2. Electronic/electric balance.
An electronic/electric balance has a pan where a substance of unknown mass is placed. The mass of the unknown substance in grams is available immediately on the screen.
(c)Apparatus for measuring temperature
A thermometer has alcohol or mercury trapped in a bulb with a thin enclosed outlet for the alcohol/mercury in the bulb.
If temperature rises in the bulb, the alcohol /mercury expand along the thin narrow enclosed outlet.
The higher the temperature, the more the expansion
Outside, a calibration /graduation correspond to this expansion and thus changes in temperature.
A thermometer therefore determines the temperature when the bulb is fully dipped in to the substance being tested. To determine the temperature of solid is thus very difficult.
(d)Apparatus for measuring time
The stop watch/clock is the standard apparatus for measuring time. Time is measured using hours, minutes and second.
Common school stop watch/clock has start, stop and reset button for determining time for a chemical reaction. This requires practice.
(e) Apparatus for scooping
1. Spatula
A spatula is used to scoop solids which do not require accurate measurement. Both ends of the spatula can be used at a time.
A solid scooped to the brim is “one spatula end full” A solid scooped to half brim is “half spatula end full”.
2. Deflagrating spoon
A deflagrating spoon is used to scoop solids which do not require accurate measurement mainly for heating. Unlike a spatula, a deflagrating spoon is longer.
(f) Apparatus for putting liquids/solid for heating.
1. Test tube.
A test tube is a narrow/thin glass apparatus open on one side. The end of the opening is commonly called the “the mouth of the test tube”.
2. Boiling/ignition tube.
A boiling/ignition tube is a wide glass apparatus than a test tube open on one side. The end of the opening is commonly called the “the mouth of the boiling/ignition tube”.
3. Beaker.
Beaker is a wide calibrated/graduated lipped glass/plastic apparatus used for transferring liquid solution which do not normally require very accurate measurements
Beakers are named according to the maximum calibrated/graduated volume they can hold e.g.
“250ml” beaker has a maximum calibrated/graduated volume of “250mililitres” /“250 cubic centimeters”
“1l” beaker has a maximum calibrated/graduated volume of “one litre” /“1000 cubic centimeters”
“5 l” beaker has a maximum calibrated/graduated volume of “two litres” /“2000 cubic centimeters”
4. Conical flask.
A conical flask is a moderately narrow glass apparatus with a wide base and no calibration/graduation. Conical flasks thus carry/hold exact volumes of liquids that have been measured using other apparatus. It can also be put some solids. The narrow mouth ensures no spillage.
Conical flasks are named according to the maximum volume they can hold e.g. “250ml” Conical flasks hold a maximum volume of “250mililitres” /“250 cubic centimeters”
“500ml” Conical flasks hold a maximum volume of “500ml” /“1000 cubic centimeters”
5. Round bottomed flask
A round bottomed flask is a moderately narrow glass apparatus with a wide round base and no calibration/graduation. Round bottomed flask thus carry/hold exact volumes of liquids that have been measured using other apparatus. The narrow/thin mouth prevents spillage. The flask can also hold (weighed) solids. A round bottomed flask must be held/ clamped when in use because of its wide narrow base.
6. Flat bottomed flask
A flat bottomed flask is a moderately narrow glass apparatus with a wide round base with a small flat bottom. It has no calibration/graduation.
Flat bottomed flasks thus carry/hold exact volumes of liquids that have been measured using other apparatus. The narrow/thin mouth prevents spirage. They can also hold (weighed) solids. A flat bottomed flask must be held/ clamped when in use because it’s flat narrow base is not stable.
(g) Apparatus for holding unstable apparatus (during heating).
1. Tripod stand
A tripod stand is a three legged metallic apparatus which unstable apparatus are placed on (during heating).Beakers. Conical flasks, round bottomed flask and flat bottomed flasks are placed on top of tripod stand (during heating).
2. Wire gauze/mesh
Wire gauze/mesh is a metallic/iron plate of wires crossings. It is placed on top of a tripod stand:
(i) Ensure even distribution of heat to prevent cracking glass apparatus
(ii) Hold smaller apparatus that cannot reach the edges of tripod stand
3 Clamp stand
A clamp stand is a metallic apparatus which tightly hold apparatus at their “neck” firmly.
A clamp stand has a wide metallic base that ensures maximum stability. The height and position of clamping is variable. This require practice
4. Test tube holder
A test tube holder is a hand held metallic apparatus which tightly hold test/boiling/ignition tube at their “neck” firmly on the other end.
Some test tube holders have wooden handle that prevent heat conduction to the hand during heating.
5. Pair of tong.
A pair of tong is a scissor-like hand held metallic apparatus which tightly hold firmly a small solid sample on the other end.
6. Gas jar
A gas jar is a long wide glass apparatus with a wide base.
It is open on one end. It is used to collect/put gases.
This requires practice.
(h) Apparatus for holding/directing liquid solutions/funnels (to avoid spillage).
1. Filter funnel
A filter funnel is a wide mouthed (mainly plastic) apparatus that narrow drastically at the bottom to a long extension.
When the long extension is placed on top of another apparatus, a liquid solution can safely be directed through the wide mouth of the filter funnel into the apparatus without spirage.
Filter funnel is also used to place a filter paper during filtration.
2. Thistle funnel
A thistle funnel is a wide mouthed glass apparatus that narrow drastically at the bottom to a very long extension.
The long extension is usually drilled through a stopper/cork.
A liquid solution can thus be directed into a stoppered container without spillage
3. Dropping funnel
A dropping funnel is a wide mouthed glass apparatus with a tap that narrow drastically at the bottom to a very long extension.
The long extension is usually drilled through a stopper/cork.
A liquid solution can thus be directed into a stoppered container without spillage at the rate determined by adjusting the tap.
4. Separating funnel
A separating funnel is a wide mouthed glass apparatus with a tap at the bottom narrow extension.
A liquid solution can thus be directed into a separating funnel without spillage. It can also safely be removed from the funnel by opening the tap.
It is used to separate two or more liquid solution mixtures that form layers/immiscible. This requires practice.
(h) Apparatus for heating/Burners
1. Candle, spirit burner, kerosene stove, charcoal burner/jiko are some apparatus that can be used for heating.
Any flammable fuel when put in a container and ignited can produce some heat.
2. Bunsen burner
The Bunsen burner is the standard apparatus for heating in a Chemistry school laboratory.
It was discovered by the German Scientist Robert Wilhelm Bunsen in1854.
(a)Diagram of a Bunsen burner
A Bunsen burner uses butane/laboratory gas as the fuel. The butane/laboratory gas is highly flammable and thus usually stored safely in a secure chamber outside Chemistry school laboratory. It is tapped and distributed into the laboratory through gas pipes.
The gas pipes end at the gas tap on a chemistry laboratory bench .If opened the gas tap releases butane/laboratory gas. Butane/laboratory gas has a characteristic odor/smell that alerts leakages/open gas tap.
The Bunsen burner is fixed to the gas tap using a strong rubber tube.
The Bunsen burner is made up of the following parts:
(i) Base plate –to ensure the burner can stand on its own
(ii)Jet-a hole through which laboratory gas enters the burner
(iii)Collar/sleeve-adjustable circular metal attached to the main chimney/burell with a side hole/entry. It controls the amount of air entering used during burning.
(iv)Air hole- a hole/entry formed when the collar side hole is in line with chimney side hole. If the collar side hole is not in line with chimney side hole, the air hole is said to be “closed” If the collar side hole is in line with chimney side hole, the air hole is said to be “open”
(v)Chimney- tall round metallic rod attached to the base plate.
(b)Procedure for lighting/igniting a Bunsen burner
1. Adjust the collar to ensure the air holes are closed.
2. Connect the burner to the gas tap using a rubber tubing. Ensure the rubber tubing has no side leaks.
3. Turn on the gas tap.
4. Ignite the top of the chimney using a lighted match stick/gas lighter/wooden splint.
5. Do not delay excessively procedure (iv) from (iii) to prevent highly flammable laboratory gas from escaping/leaking.
(c)Bunsen burner flames
A Bunsen burner produces two types of flames depending on the amount of air entering through the air holes.
If the air holes are fully open, a non luminous flame is produced. If the air holes are fully closed, a luminous flame is produced. If the air holes are partially open/ closed, a hybrid of non luminous and luminous flames is produced.
Characteristic differences between luminous and non-luminous flame
Luminous flame
Non-luminous flame
1. Produced when the air holes are fully/completely closed.
1. Produced when the air holes are fully/completely open.
2. when the air holes are fully/ completely closed there is incomplete burning/ combustion of the laboratory gas
2.when the air holes are fully/ completely open there is complete burning/ combustion of the laboratory gas
3. Incomplete burning/ combustion of the laboratory gas produces fine unburnt carbon particles which make the flame sooty/smoky
3. Complete burning/ combustion of the laboratory gas does not produce carbon particles. This makes the flame non-sooty /non- smoky.
4. Some carbon particles become white hot and emit light. This flame is thus bright yellow in colour producing light. This makes luminous flame useful for lighting
4. Is mainly blue in colour and is hotter than luminous flame. This makes non-luminous flame useful for heating
5. Is larger, quiet and wavy/easily swayed by wind
5.Is smaller, noisy and steady
Luminous flame has three main regions:
(i)the top yellow region where there is incomplete combustion/burning
(ii)the region of unburnt gas below the yellow region where the gas does not burn
(iii) blue region on the sides of region of unburnt gas where there is complete burning
Non-luminous flame has four main regions:
(i)the top colourless region
(ii) Blue region just below where there is complete burning. It is the hottest region
(iii) green region surrounded by the blue region where there is complete burning
(Ii) The region of unburnt gas at the innermost surrounded by green and blue regions. No burning takes place here
Scientific apparatus are drawn:
(i) Using a proportional two dimension (2D) cross-sections. Three dimensions (3D) are not recommended.
(ii) Straight edges of the apparatus on a scientific diagram should be drawn using ruler.
(iii) Curved edges of the apparatus on a scientific diagram should be drawn using free hand.
(iv)The bench, tripod or clamp to support apparatus which cannot stand on their own should be shown.
CLASSIFICATION OF SUBSTANCES
Substances are either pure or impure. A pure substance is one which contains only one substance.
An impure substance is one which contains two or more substances. A pure substance is made up of a pure solid, pure liquid or pure gas.
A mixture is a combination of two or more pure substances which can be separated by physical means. The three states of matter in nature appear mainly as mixtures of one with the other.
Common mixtures include:
(a)Solutions/solid-liquid dissolved mixture
Experiment:
To make a solution of copper (II) sulphate (VI)/Potassium magnate(VII) /sodium chloride
Procedure
Put about 100 cm3 of water in three separate beakers. Separately place a half spatula end full of copper (II) sulphate (VI), Potassium manganate (VII) and sodium chloride crystals to each beaker. Stir for about two minutes.
Observation
Copper (II) sulphate (VI) crystals dissolve to form a blue solution
Potassium manganate (VII) crystals dissolve to form a purple solution
Sodium chloride crystals dissolve to form a colourless solution
Explanation
Some solids, liquids and gases dissolve in some other liquids.
A substance/liquid in which another substance dissolves is called solvent.
A substance /solid /gas which dissolves in a solvent is called solute.
When a solute dissolves in a solvent it forms a uniform mixture called solution.
A solute dissolved in water as the solvent exists in another state of matter called aqueous state. Water is referred as the universal solvent because it dissolves many solutes. A solute that dissolves in a solvent is said to be soluble. Soluble particles uniformly spread between the particles of water/solvent and cannot be seen.
Solute + Solvent -> solution
Solute + Water -> aqueous solution of solute
The solute dissolved in water gives the name of the solution e. g.
1. Sodium chloride solution is a solution formed after dissolving sodium chloride crystals/solid in water. Sodium chloride exists in aqueous state after dissolving.
Sodium chloride + Water -> Sodium chloride solution
NaCl(s) + (aq) -> NaCl(aq)
2. Ammonia solution is a solution formed after dissolving ammonia gas in water. Ammonia exists in aqueous state after dissolving.
Ammonia gas + Water -> aqueous ammonia
NH3 (g) + (aq) -> NH3 (aq)
3. Copper (II) sulphate (VI) solution is a solution formed after dissolving Copper (II) sulphate (VI) crystals/solid in water. Copper (II) sulphate (VI) exists in aqueous state after dissolving.
Copper (II) sulphate (VI) + Water -> Copper (II) sulphate (VI) solution
CuSO4(s) + (aq) -> CuSO4 (aq)
4. Potassium manganate(VII) solution is a solution formed after dissolving Potassium manganate(VII) crystals/solid in water.
Potassium manganate(VII)exist in aqueous state after dissolving.
Potassium manganate(VII) + Water -> Potassium manganate(VII) solution
KMnO4(s) + (aq) -> KMnO4 (aq)
(b)Suspension/ precipitates/solid-liquid mixture which do not dissolve
Experiment: To make soil, flour and Lead (II) Iodide suspension/precipitate
Procedure
Put about 100 cm3 of water in three separate beakers. Separately place a half spatula end full of soil, maize and lead (II) Iodide to each beaker. Stir for about two minutes.
Observation
Some soil, maize and lead (II) Iodide float in the water
A brown suspension/precipitate/particles suspended in water containing soil
A white suspension/precipitate/particles suspended in water containing flour
A yellow suspension/precipitate/particles suspended in water containing Lead (II) iodide. Some soil, maize and lead (II) Iodide settle at the bottom after some time.
Explanation
Some solid substances do not dissolve in a liquid. They are said to be insoluble in the solvent .When an insoluble solid is put in liquid:
(i) Some particles remain suspended/floating in the liquid to form a suspension /precipitate.
(ii) Some particles sink/settle to the bottom to form sediments after being allowed to stand.
An insoluble solid acquire the colour of the suspension/precipitate .e.g.
1. A white suspension /precipitate have some fine white particles suspended /floating in the liquid. Not “white solution”
2. A blue suspension /precipitate has some fine blue particles suspended /floating in the liquid.
3. A green suspension /precipitate has some fine green particles suspended /floating in the liquid.
4. A brown suspension /precipitate has some fine brown particles suspended /floating in the liquid.
4. A yellow suspension /precipitate has some fine yellow particles suspended /floating in the liquid.
(c) (i) Miscibles /Liquid-liquid mixtures
To form water-ethanol and Kerosene-turpentine miscibles
Procedure
(i)Measure 50cm3 of ethanol into 100cm3 beaker. Measure 50cm3 of water. Place the water into the beaker containing ethanol. Swirl for about one minute.
(ii)Measure 50cm3 of kerosene into 100cm3 beaker. Measure 50cm3 of turpentine oil. Place the turpentine oil into the beaker containing kerosene. Swirl for about one minute.
Observation
Two liquids do not form layers.
Ethanol and water form a uniform mixture.
Kerosene and turpentine oil form uniform mixture
Explanation
Ethanol is miscible in Water. Kerosene is miscible in turpentine oil. Miscible mixture form uniform mixture. They do not form layers. The particles of one liquid are smaller than the particles of the other. The smaller particles occupy the spaces between the bigger particles.
Immiscibles /Liquid-liquid mixtures
To form water-turpentine oil and Kerosene-water miscibles
Procedure
(i)Measure 50cm3 of water into 100cm3 beaker. Measure 50cm3 of turpentine oil. Place the oil into the beaker containing water. Swirl for about one minute.
(ii) Measure 50cm3 of water into 100cm3 beaker. Measure 50cm3 of kerosene. Place the kerosene into the beaker containing water. Swirl for about one minute.
Observation
Two liquids form layers.
Turpentine and water do not form a uniform mixture.
Water and kerosene do not form uniform mixture
Explanation
Kerosene is immiscible in Water. Water is immiscible in turpentine oil. Immiscible mixtures do not form uniform mixtures. They form layers. The size of the particles of one liquid is almost equal to the particles of the other. The particles of one liquid cannot occupy the spaces between the particles of the other. The heavier particles settle at the bottom. The less dense particles settle on top.
(d)Solid-solid mixtures/Alloys
Before solidifying, some heated molten/liquid metals dissolve in another metal to form a uniform mixture of the two. On solidifying, a uniform mixture of the metals is formed. A uniform mixture of two metals on solidifying is called alloy. In the alloy, one metallic particle occupies the spaces between the metallic particles of the other.
c) Common alloys of metal.
Alloy name
Constituents of the alloy
Uses of the alloy
Brass
Copper and Zinc
Making screws and bulb caps
Bronze
Copper and Tin
Making clock springs, electrical contacts and copper coins
Soldier
Lead and Tin
Soldering, joining electrical contacts because of its low melting points and high thermal conductivity
Duralumin
Aluminum, Copper and Magnesium
Making aircraft, utensils, and windows frames because of its light weight and corrosion resistant.
Steel
Iron, Carbon ,Manganese and other metals
Railway lines, car bodies girders and utensils.
Nichrome
Nichrome and Chromium
Provide resistance in electric heaters and ovens
German silver
Copper, Zinc and Nickel
Making coins
METHODS OF SEPARATING MIXTURES
Mixtures can be separated from applying the following methods:
(a) Decantation
Sediments can be separated from a liquid by pouring out the liquid. This process is called decantation.
Experiment
Put some sand in a beaker. Add about 200cm3 of water. Allow sand to settle. Pour off water carefully into another beaker.
Observation
Sand settles at the bottom as sediments.
Less clean water is poured out.
Explanation
Sand does not dissolve in water. Sand is denser than water and thus settles at the bottom as sediment. When poured out, the less dense water flows out.
(b)Filtration
Decantation leaves suspended particles in the liquid after separation. Filtration is thus improved decantation.Filtration is the method of separating insoluble mixtures/particles/solids from a liquid.
Experiment: To separate soil and water using filtration
Fold a filter paper to fit well into a filter funnel. Place the funnel in an empty 250 cm3 beaker.
Put one spatula end full of soil into 50cm3 of water. Stir. Put the soil/water mixture into the filter funnel.
Observations
Clean water is collected below the filter funnel.
Soil remains above the filter paper.
Explanation
A filter paper is porous which act like a fine sieve with very small holes. The holes allow smaller water particles to pass through but do not allow bigger soil particles. The liquid which passes through is called filtrate. The solid which do not pass through is called residue.
Set up of apparatus
In industries, filtration is used in engine filters to clean up air.
(c)Evaporation
Evaporation is a method of separating a solute/solid from its solution. This involves heating a solution (solvent and solute)to vapourize the solvent out of the solution mixture leaving pure solute/solid. If a mixture contain insoluble solid, they are filtered out.
Experiment: To separate a mixture of soil and salt (sodium chloride).
Procedure:
Put one spatula end full of soil on a filter paper.
Put one spatula full of common salt/sodium chloride into the same filter paper. Mix well using the spatula,.
Place about 200cm3 of water into a beaker.
Put the contents of the filter paper into the water. Stir thoroughly using a glass/stirring rod for about one minute.
Fold a filter paper into a filter funnel.
Pour half portion of the contents in the beaker into the filter funnel.
Put the filtrate into an evaporating dish. Heat on a water bath.
Observation
(i)On mixing
Colourless crystals and brown soil particles appear on the filter paper.
(ii)On adding water
Common soil dissolves in water. Soil particles do not dissolve in water.
(iii)On filtration
Colourless liquid collected as filtrate below the filter funnel/paper.
Brown residue collected above the filter funnel/paper.
(iv)On evaporation
Colourless crystals collected after evaporation
Explanation
Solid mixture of sand and common salt take the colors of the two.
On adding water, common salt dissolves to form a solution.
Soil does not because it is insoluble in water and thus forms a suspension.
On filtration, a residue of insoluble soil does not pass through the filter paper.
It is collected as residue.
Common salt solution is collected as filtrate.
On heating the filtrate, the solvent/water evaporate/vaporize out of the evaporating dish leaving common salt crystals.
Vapourization/evaporation can take place even without heating.
This is the principle/process of drying wet clothes on the hanging line.
Set up of apparatus
(d) Distillation
Distillation is an improved evaporation where both the solute and the solvent in the solution are separated /collected. Distillation therefore is the process of separating a solution into constituent solid solute and the solvent. It involves heating the solution to evaporate/vaporize the solvent out. The solvent vapour is then condensed back to a liquid.
Experiment: To obtain copper (II) sulphate (VI) crystals and water from copper (II) sulphate (VI) solution.
Procedure:
Put one spatula end full of copper (II) sulphate (VI) crystals into a 250cm3 beaker.
Place about 200cm3 of water into the beaker.
Stir thoroughly using a glass/stirring rod for about one minute.
Pour half portion of the contents in the beaker into a round bottomed/flat/conical flask broken porcelain/sand/glass into the flask.
Put a few pieces of b Stopper the flask.
Connect the flask to a Liebig condenser using delivery tube.
Place a 200cm3 clean empty beaker/conical flask as a receiver at the end of the Liebig condenser.
Circulate water in the Liebig condenser.
Heat the flask strongly on a tripod stand with wire mesh/gauze until there is no more visible boiling bubbles in the flask.
Observation
Copper (II) sulphate (VI) crystals dissolve in water to form a blue solution.
On heating, colourless liquid is collected in the receiver.
Blue crystals are left in the flask.
(If gently heated further, the blue crystals turn to white powder)
Explanation
On heating blue Copper (II) sulphate (VI) solution, the colourless liquid solvents evaporate/vaporize.
The liquid vapour/gas passes through the delivery tube to the Liebig condenser.
The Liebig condenser has a cold water inlet near the receiver and cold water out let.
This ensures efficient cooling. If the cold water outlet/inlet is reversed, the water circulation would be less efficient.
The water in the receiver would be warm. In the Liebig condenser, the cold water condenses the liquid vapour into liquid.
The condensed liquid collects in the receiver as distillate.
The solute of blue Copper (II) sulphate (VI) crystals is left in the flask as residue.
During simple distillation, therefore, the solution is heated to vaporize /evaporate the solvent/one component which is condensed at a different part of the apparatus.
The purpose of pieces of broken porcelain/porous pot/glass/sand/ is to:
(i) Prevent bumping of the solution during boiling.
(ii) Ensure smooth and even boiling.
Salty sea water can be made pure through simple distillation.
Any mixture with a large difference /40oC in boiling point can be separated using simple distillation.
Set up of apparatus
e)Fractional distillation
Fractional distillation is an improved simple distillation used specifically to separate miscible mixtures with very close /near boiling points.
Fractional distillation involves:
(i) Heating the mixture in a conical/round bottomed /flat bottomed flask.
