OCR A-Level Chemistry PAGs
What is needed to carry out "heating under reflux"? - ANSWER
✔✔Equipment: Vertical condenser (clamps etc), Pear-shaped flask,
antibumping granules, grease/vaseline and a heat source
*Antibumping granules*-used to make the liquid boil calmly and prevent
bumping, bubbles and liquid from being expelled.
*Vaseline*-Makes the join airtight and prevents them from freezing in
certain reactions
How do you carry out "heating under reflux"? - ANSWER ✔✔Set up
the equipment as shown in the diagram.
Add the reaction mix into the flask with antibumping granules.
Add grease/vaseline between the flask and condenser joint.
,Clamp the flask/condenser joint to ensure it doesn't fall.
Connect the tubing (water in at the bottom out on top) and start the
reflux.
What is the purpose of reflux? - ANSWER ✔✔It enables a liquid to be
continually boiled whilst the reaction takes place. This prevents volatile
components from escaping and the flask boiling dry.
The vapour rises in the inner tube till it meets the outer tube containing
cold water.
The vapour condenses and drips back into the falsk.
What equipment is needed to carry out "distillation"? - ANSWER
✔✔Equipment: Condenser (clamps etc), Pear-shaped flask, antibumping
granules, grease/vaseline, still head, receiver, screw-tap adaptor,
thermometer and a heat source.
How do you carry out "distillation"? - ANSWER ✔✔Place the reaction
mixture in the pear shaped glass. Apply grease at the joints and put the
quickfit apparatus together.
Clamp the flask/still head joint and the condenser joint. Put a flask at the
bottom of the receiver. Grease is used to ensure the apparatus comes
apart easily. Cold water in at the bottom.
,What is the purpose of distillation? - ANSWER ✔✔To separate pure
liquids from their impurities. Each liquid will have a specific boiling point
(the lowest will boil first and is more volatile). The vapour leaves the flask
and enters into the cold condenser, where it condenses and becomes a
liquid.
How can a organic products be purified? - ANSWER ✔✔Using a
separating funnel. Identify the organic layer by adding in H₂O, the
organic layer will remain the same size. After:
1.Ensure the separating funnel tap is closed.
2.Pour the mixture into the funneland place a stopper. Begin to invert it.
3.Place it in a clamp and allow it to settle. Add H₂O again to identify the
aqueous layer.
4.Remove the stopper and allow the whole lower layer to leave the
funnel.
5.The organic product has been purified.
How can acids from organic products be purified? - ANSWER ✔✔By
adding aqueous sodium carbonate and shaking the mix in a separating
funnel. The acid will react with the base to produce Co₂.
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2026. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
3
, Bc of this the tap needs to be opened slowly and away from you to
release any pressure built up.
Why do some organic products need to be dried? - ANSWER ✔✔To
remove excess water a drying agent is used. Normally anhydrous salts
are used (MgSO₄, CaCl₂), they readily take up water to become
hydrated. The salts above are used for general drying and calcium
chloride is used for dring hydrocarbons.
How do you dry organic products? - ANSWER ✔✔1.Add the product
to a conical flask
2.Use a spatula to add some drying agent and swirl the mix gently.
3.Place a stopper to prevent evaporation (10mins)
4.Is the solid is lumped H₂O is still present - add more agent and repeat
2-3.
5.If a fine powder forms decant (gradually pour) the liquid from the solid
into a another flask - the liquid should be clear.
Why does redillation need to be carried out? - ANSWER ✔✔Some
organics have similar boiling points so the prepared sample may still
have impurities. Distillation is done again, the same apparatus is
cleaned and dried. The compound required is then distilled.
What is needed to carry out "heating under reflux"? - ANSWER
✔✔Equipment: Vertical condenser (clamps etc), Pear-shaped flask,
antibumping granules, grease/vaseline and a heat source
*Antibumping granules*-used to make the liquid boil calmly and prevent
bumping, bubbles and liquid from being expelled.
*Vaseline*-Makes the join airtight and prevents them from freezing in
certain reactions
How do you carry out "heating under reflux"? - ANSWER ✔✔Set up
the equipment as shown in the diagram.
Add the reaction mix into the flask with antibumping granules.
Add grease/vaseline between the flask and condenser joint.
,Clamp the flask/condenser joint to ensure it doesn't fall.
Connect the tubing (water in at the bottom out on top) and start the
reflux.
What is the purpose of reflux? - ANSWER ✔✔It enables a liquid to be
continually boiled whilst the reaction takes place. This prevents volatile
components from escaping and the flask boiling dry.
The vapour rises in the inner tube till it meets the outer tube containing
cold water.
The vapour condenses and drips back into the falsk.
What equipment is needed to carry out "distillation"? - ANSWER
✔✔Equipment: Condenser (clamps etc), Pear-shaped flask, antibumping
granules, grease/vaseline, still head, receiver, screw-tap adaptor,
thermometer and a heat source.
How do you carry out "distillation"? - ANSWER ✔✔Place the reaction
mixture in the pear shaped glass. Apply grease at the joints and put the
quickfit apparatus together.
Clamp the flask/still head joint and the condenser joint. Put a flask at the
bottom of the receiver. Grease is used to ensure the apparatus comes
apart easily. Cold water in at the bottom.
,What is the purpose of distillation? - ANSWER ✔✔To separate pure
liquids from their impurities. Each liquid will have a specific boiling point
(the lowest will boil first and is more volatile). The vapour leaves the flask
and enters into the cold condenser, where it condenses and becomes a
liquid.
How can a organic products be purified? - ANSWER ✔✔Using a
separating funnel. Identify the organic layer by adding in H₂O, the
organic layer will remain the same size. After:
1.Ensure the separating funnel tap is closed.
2.Pour the mixture into the funneland place a stopper. Begin to invert it.
3.Place it in a clamp and allow it to settle. Add H₂O again to identify the
aqueous layer.
4.Remove the stopper and allow the whole lower layer to leave the
funnel.
5.The organic product has been purified.
How can acids from organic products be purified? - ANSWER ✔✔By
adding aqueous sodium carbonate and shaking the mix in a separating
funnel. The acid will react with the base to produce Co₂.
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2026. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
3
, Bc of this the tap needs to be opened slowly and away from you to
release any pressure built up.
Why do some organic products need to be dried? - ANSWER ✔✔To
remove excess water a drying agent is used. Normally anhydrous salts
are used (MgSO₄, CaCl₂), they readily take up water to become
hydrated. The salts above are used for general drying and calcium
chloride is used for dring hydrocarbons.
How do you dry organic products? - ANSWER ✔✔1.Add the product
to a conical flask
2.Use a spatula to add some drying agent and swirl the mix gently.
3.Place a stopper to prevent evaporation (10mins)
4.Is the solid is lumped H₂O is still present - add more agent and repeat
2-3.
5.If a fine powder forms decant (gradually pour) the liquid from the solid
into a another flask - the liquid should be clear.
Why does redillation need to be carried out? - ANSWER ✔✔Some
organics have similar boiling points so the prepared sample may still
have impurities. Distillation is done again, the same apparatus is
cleaned and dried. The compound required is then distilled.
