AS3 Practical Theory

1. Weigh Evapourating Basin

2. Add some Hydrated Solid and weigh the Evaporating Basin and solid.

3. Heat to a constant mass- heating for a few minutes and then cool and weigh and repeat until the mass does not change( it is constant)

1. Place the liquid in the burette and place a small beaker underneath the jet

2. Open the tap and allow a small stream of liquid to run from the burette

3. Hold a charged polythene rod close to the stream of liquid and note any deflection.

4. To compare the polarity of two liquids use two burettes simultaniously with a stream if liquid at the same rate and distance between the charged rod and liquid constant.

1. Set up a circuit using a dc power pack and bulb

2. Add graphite electrodes into the circuit and dip them into a beaker of liquid/aqueous solution, ensuring they do not touch

3. Switch on the power pack and record if the bulb lights 

4.  To test electrical conductivity of a solid, place the solid between crocodile clips

1 Add 1 cm3 of each of the aqueous halogen solutions (chlorine water, iodine solution) into separate test-tubes

2 Add equal volumes of a saturated hydrocarbon solvent e.g. hexane to each tube, stopper the tube and, shake the mixture by inverting the test-tube a few times.

3 Allow the two layers to settle; observe and record the colour

1. Add 1 cm3 of each aquaous halogen solutions into separate test tubes.

2. Add 1 cm3 of KCl solution to each and record Colour Change

3. Repeat experiment for KBr and KI solutions .

4. A Saturated hydrocarbon eg Hexane can be added to distinguish between Bromine and Iodine or Starch solution couldbe added to detect Iodine

1. Add 1 spatula of KCl(s) in test tube

2. Add few drops of  conc. H2SO4 record observations -

(MHaI(s)+H2SO4(aq) ----- HHal(g) + MHSO4(s)

3. Test gas evolved - HCl - dip glass rod into conc. NH3 and into test tube - white copious fume produced

4. Repeat using KBr - Red Brown Vapour

5 Repeat using KI - Purple/Violet Vapour, Smell of Rotten Eggs (H2S),Yellow Solid (S), Grey- Black solid on sides (I2)

* Generic Observations include - Misty Fumes of HHal(g)

1. Rinse Pipette with solution to be transferred to Conical Flask

2. Using Pipette and Pipette filler place solution into conical flash (eg. 25cm3)

3. Rinse burette with solution to be place in it and then fill burette to one or two decimal places- second decimal place should be 0 OR 5

4. Add 3-5 drops of suitable indicator to conical flask

Methyl Orange - Strong Acid-Strong Base / Strong Acid- Weak Base

Phenolphalein - Strong Acid- Stong Base/ Weak Acid- Strong Base

5. Add solution from burette with swirling until the indicator changes colour.

Methyl Orange- Red(Alkali) to Yellow(Acid)

Phenolphalein- Pink(Alkali) to Colourless( Acid)

6. Record to 2 dp and ensure that results are Concordant - within +/- 0.1 cm3

1. Rinse the apparatus with the appropriate solution

2. Add the solution form the burette dropwise just before the end point

3. Swirl flask

4. Read the burette at the bottom of the meniscus

1. Calculate the required mass of the solid/liquid required to make the solution ( or the required volume of liquid)

2. Weigh the solid/liquid in a a beaker on a top pan balance( or measure the volume of the liquid using a graduated pipette/burette/measuring cylinder.

3. Dissolve the solid in a small volume (50-100cm3) of deionied water.

4. Transfer the solution to the appropriately sized volumetric flask

5. Rinse the beaker and glass rod with deioniesed water and add washings to the volumetric flask

6 Make up to the mark by adding deionised water until the bottom of the meniscus is on the mark

7. Stopper the flask and invert to mix

1. Dip the Nichrome Wire loop into Concentrated HCl

2. Dip the wire into the test solid

3. Hold the wire in a clean blue bunsen flame

4. Note the colour of the flame

Colours Observed

Li+  - Crimson

Na+ - yellow/ orange

K+ - lilac / pink through cobalt glass

Ca2+ - brick red

Ba2+ - apple green/ green

Cu2+ - green-blue/ blue-green

1. Warm the solid with solution of NaOH

2. Test any gas produced with a glass rod dipped in Conc HCL or the stopper of a bottle of HCl acid bottle

Pungent smell of NH3

NH₄⁺ (aq) + OH- (aq) → NH₃ (g) + H₂O (l)

Ammonia has a characteristic sharp, choking smell. It makes damp litmis paper turn blue. It forms a white smoke of ammonium chloride when it comes into contact with hydrogen chloride gas, from concentrated hydrochloric acid.

1. If supplied with a solid, first make a solution of the salt eg a spatular measure in a test tube half filled with deionsed water

2. Add 1cm3 of BaCl2 or BaN03 solution - forms white ppt

Sulfate ions in solution, SO₄^2-, are detected using barium chloride solution. The test solution is acidified using a few drops of dilute hydrochloric acid, and then a few drops of barium chloride solution are added. A white ppt of barium sulfate forms if sulfate ions are present.

BaCl₂(aq) + Na₂SO₄(aq) → 2NaCl(aq) + BaSO₄(s)

1. If supplied as a solid make into a solution of the Halide Salt in dilute Nitric Acid.

2. Add 1 cm3 AgNO3 solution

3. Add 1 cm3 of NH3 solution

4.Add Excess dilute NH3 solution (5cm3)

5 If precipitate remains repeat using concentrated NH3 solution

Observations

• chloride ions give a white precipitate of silver chloride
• bromide ions give a cream precipitate of silver bromide
• iodide ions give a yellow precipitate of silver iodide

AgNO₃(aq) + NaBr(aq) → NaNO₃(aq) + AgBr(s)

1. To the solid add some dilute acid. If there is effervescene collect the gas and bubble into limewater

Limewater turns milky in CO2 . Redissolves in excess

  Ca(OH)_2(aq)+ CO_2(g)  CaCO_3(s)+  H₂O_(l)

1. Add a few cm3 of Br2 and shake

Discolourises in presence of C=C

1. Place 10g of NaBr in pear shaped flask

2. Add 7.5cm3 of butan-1-ol and 10cm3 of H20

3. Lower into beaker of cold water

4. Add 10 cm3 of H2SO4 slowly with swirling

5.Add some anti-bumping granules

6.Gently reflux mixture for 30-45 minutes.

7. Distill off the impure bromobutane

8. Remove unreacted butan-1-ol by shaking with conc. HCl in separating funnel.

9. Remove the acidic impurities from inpure product by adding NaHSO4

10.Dry the impure product by using anhydrous salt

11. Purify the product using simple distillation

The condensor in upright position

A flask

A hear source

The water flowing correclty though the condenser

Use of antibumping granules

Any gaps at the joints or a closed apparatus will be penalised

The condenser in sideward position.

Pear shaped Flask

Still Head

Thermometer

Heat Source

Water flowing correctly

Measuring Cylinder

Use of Antibumping Granules

1.Place the impure distillate in the separating funnel

2. Add NaCO3 /NaHCO3 solution.

3. Stopper and Shake

4.Release the pressure at regular intervals by inverting and rinning off the lower layer into a beaker.

5. Allow to stand until the layers settle and separate, then run off the lower layer into a beaker,

6. Decide which is the aquaous layer by referring to density or adding some deionised water and observing what layer increases in size.

7. Discard the aquaous layer

1. Place the impure liquid product in a beaker or concial flask

2. Add a spatula of a drying agent eg Anhydrous Soduim Sulfate or Anhydrous Calcuim Chloride/ Anhydrous Magnesium Sulfate.

3. Swirl

4. Add more of the drying agent until the liquid is clear / no longer cloudy

5. Decant or filter off liquid

1. Place the Halogenoalkane in a pear shaped flask

2. Add some dilute NaOH

3. Heat under Reflux

4. Distill off the Alcohol

Generic Equation

Halogenoalkane + OH- ---- Alcohol + Hal(-)

Conditions ; Heat under reflux with NaOH(aq) and small quantity of CH3CH2OH for 1 hr

1. Use halogenoalkanes with the came chain length and place 1cm3 of  the chloroalkane, bromoalkane and iodoalkane into separate test tubes

2. Add an equal volume of Ethanol (approx 1cm3) to each test tube

3. Add equal volumes of AgNO3 (approx 1 cm3) to each test tube

4. Place test tubes in hot water bath at 50 C and start stopwatch

5. Time how long it takes for each precipitate to form

Rate of Reaction = 1/time taken

When Alkene is Liquid

1. Place 2cm3 of Ethanolic KOH into a flask

2. Add 1 cm3 of Halogenoalkane

3. Shake and add anti-bumping granules

4.Reflux gently for 20 minutes

5. Set up for distillation and collect product

6. Test with Br2

Generic Equation

Halogenoalkane + KOH ---- Alkene +KHal +H20

Conditions; Halogenoalkane treated with hot ethanolic KOH/NaOH solution

If alkene is Gaseous

1. Some sand soaked with liquid Halogenoalkane, placed into boiling tube and clamped horizontally

2. Add some KOH pellets in Ceramic Wool soaked in Ethanol and placed in middle of boiling tube.

3. Heat the halogenoalkane with Ethanolic KOH and collect gas produced over water

4. Test gas with Br2

1. Place 5cm3 of Alcohol into bioling tube

2. Cut 2x2x2 mm of Na and use filter paper to remove excess oil from it

3. Add piece of Na to alcohol and observe

4. Place 1cm3 of alcohol to boiling tube and add spatula of PCl5 and record observations.

Alcohol with Sodium

Alcohol + Sodium ---- Sodium alkoxide(eth-oxide) + Hydrogen

Alcohol with HBr

Alcohol + HBr ----- Halogenoalkane + H20

Alcohol with PCl5

Alcohol + PCl5 ------ Chloroalkane + Phosphorous Oxochloride(POCl3) + HCl

1. Add Acidified K2Cr2O7 solution in excess to pear shaped flask and set up for reflux

2. Add antibumping granules

3. Add a volume of primaryalcohol slowly down the condenser from a dropping funnel nad cool in a waterbath.

4. Remove waterbath and heat mixture under reflux

5.Rearrange the apparatus for distilation and distill off acid

Primary Alcohol + 2[O] ---- Carboxylic Acid + Water

1. Add K2Cr2O7 in excess to pear shaped flask

2. Add antibumping granules

3. Add volume of Primary Alcohol

4. Assemble the apparatus for distillation- this removes the aldehyde from the oxidising mixture immediately and prevents further oxidation to a Carboxylic Acid

Primary Alcohol + [0] --- Aldehyde + Water

1. Add K2Cr2O7 in excess to pear shaped flask.

2. Set up for reflux

3. Add antibumping granules

4.Add volume of secondary alcohol slowly down the condenser from a dropping funnel and cool in waterbath.

5. Remove the water bath and heat the mixture under reflux

6. Rearrange the apparatus for distillation and distill off the Ketone

Secondary Alcohol + [O]------ Ketone + Water

1. Accurately measure out a volume eg 100cm3 of water into calorimeter/ beaker(100cm3=100g)

2. Weigh Spirit Burner containing liquid fuel to be burnt.

3. Measure inital temperature of water using thermometer(T1)

4.Use spirit burner to heat water

5.Stop heating when the liquid fuel has ran out and record final temperature (T2)

6. Reweigh Spirit Burner

7 Calculate the temperature change(^T=  T2-T1)

8. Calculate the enthalpy change by using (^H/q=mc(^T))

9 Calculate the mass of the liquid fuel used by M2-M1 and use to calculate moles

10 .Divide enthalpy change by moles to find enthalpy change per mole . This is enthalpy chage of combustion

1. Place Polystyrene cup in a galss beaker for support and further insulation to prevent draughts.

2. Using a measuring cylinder to measure volume (25.0 cm3) of a standard solution and transfer to polystyrene cup.

3. Stir the acid with a thermometer and record temperature

4. Use second measuring cylinder to measure volume (25.0cm3) of a standard solution of NaOH.

Damp Mineral Wool

Bunsen burner to beat the wool/metal

 Delivery Tube

Inverted Measuring Cylinder/ Burette under water to collect the gas and mesause volume

Trough/ Basin

Generic Reaction

M + H20 ------MO + H2

Bubbles in gas jar/ measuring cylinder

Metal in contact with the water

Inverted Filter Funnel

Inverted Measuring Cylinder/burette underwater to collect and measure the gas volume produced

Equation & Observations

M + 2H2O ----- M(OH)2 + H2

Mg - few bubbles slowly and metal dulls

Ca Sr and Ba - Heat , Bubbles Metal Dissapears

Ca reacts and forms milky (cloudy white) solution as Ca(OH)2- Ca is less soluble than other metals in water. Calcuim sinks and rises due to rapid production of H2

1 Measure the mass of crucible with lid on Top Pan Balance

2. Add some metal and measure the mass of the crucible, lid and metal

3. Place Crucible on Pipclay triangle and heat stongly, raising the lid at intervals to allow air to enter

4. Allow cruicble to cool and weigh the crucible, lid and contents

5. Repeat the heating, cooling and weighing until Constant Mass is achieved

Equation

2M + O2------- 2MO (MO dissolves in H20 producing a colourless solution when MO is solid)

Observations

• Mg burns with bright white light and produces a white ash
• Ca burns with brick red flame with white ash
• Sr burns with a red flame with white ash
• Ba burns with a green flame produces a white ash

Diagrams

• Acid in Conical Flask
• Metal
• Delivery Tube
• Gas Syringe/ Inverted Measuring cyclinder / burette underwater

Generic Equations

• MO + 2HCl ------ MCl2 +H20
• MO + H2SO4----MSO4 + H20
• MO +2HNO3----M(NO3)2 +H20

Observations

• Heat Released
• Solid Dissapears
• Colourless solution forms