EXAM: Wec Gce 2024
SUBJECT: Chemistry practical
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Waec Gce chemistry practical 👇
2a)
In a Tabular form
=TEST=
A + heat
= OBSERVATION=
Colourless, odourless gas turned limewater milky.
=INFERENCE=
CO₂ gas evolved, indicating a carbonate or bicarbonate.
(2b)
=TEST=
Residue from (a) + water + litmus paper
=OBSERVATION=
Dissolved to form a colourless solution, turned red litmus paper blue.
=INFERENCE=
Basic solution, likely an alkali such as a metal hydroxide (e.g, Ca(OH)₂).
(2c)
=TEST=
Solution from (b) + NaOH(aq) in drops, then in excess
=OBSERVATION=
White precipitate formed, soluble in excess NaOH.
=INFERENCE=
Al³⁺ ions present.
(2d)
=TEST=
B + water
=OBSERVATION=
Soluble salt.
=INFERENCE=
No direct reaction or insoluble residue indicates a soluble ionic compound.
(2e)
=TEST=
Solution from (d) + NaOH(aq) in drops, then in excess
=OBSERVATION=
White gelatinous precipitate formed; precipitate soluble in excess.
=INFERENCE=
Al³⁺ ions confirmed.
(2f)
=TEST=
Solution from (d) + NH₃(aq) in drops, then in excess
=OBSERVATION=
White precipitate formed, insoluble in excess.
=INFERENCE=
Al³⁺ ions confirmed.
(2g)
=TEST=
Solution from (d) + AgNO₃(aq) + HNO₃(aq) + NH₃(aq) in excess
=OBSERVATION=
White precipitate formed with AgNO₃, soluble in NH₃ after adding HNO₃.
=INFERENCE=
Cl⁻ ions present and confirmed.
(3a)
(i) Distillation (for liquids with different boiling points).
(ii) Fractional distillation (for miscible liquids with closer boiling points).
(3bi)
Tongs
(PICK ANY ONE)
(i) Holding hot test tubes, beakers, or crucibles during heating.
(ii) Picking up small pieces of substances or glassware.
(iii) Removing a hot lid from a container.
(iv) Gripping and placing objects into a furnace or flame.
(3bii)
Wire gauze
(PICK ANY ONE)
(i) Supporting glassware (like a beaker) over a flame.
(ii) Distributing heat evenly under a heated container.
(iii) Preventing direct contact between glass and flame to reduce breakage.
(iv) Acting as a platform for conducting flame tests.
(3biii)
Beehive shelf
(PICK ANY ONE)
(i) Supporting a gas jar during gas collection over water.
(ii) Keeping the gas jar stable while transferring gases.
(iii) Directing gas from the delivery tube into the gas jar.
(iv) Serving as an intermediary platform to avoid gas loss during collection.
(2biv)
Spatula
(PICK ANY ONE)
(i) Transferring small amounts of solid chemicals from containers.
(ii) Mixing solid substances or scooping powders for weighing.
(iii) Scraping residues from containers.
(iv) Adding controlled amounts of a solid to a reaction mixture.
(3c)
In a Tabular form
=GAS=
(i) H₂
(ii) CO₂
(iii) C₂H₂
=SOLID=
(i) Mg
(ii) CaCO₃
(iii) CaC₃
=LIQUID=
(i) Dil. HCL
(ii) Dil. HCL
(iii) Cold water
(3d)
Add dilute hydrochloric acid (HCl) to both solutions
(i) NaOH(aq): No visible reaction occurs, as it only forms water and salt.
(ii) Na₂CO₃(aq): Effervescence (bubbling) occurs due to the release of carbon dioxide gas (CO₂), which can be confirmed by bubbling it through limewater that turns milky.
waec GCE 2024 updated Timetable
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