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CAMEROON GCE ADVANCED LEVEL CHEMISTRY – Q&A NOTES (COMPREHENSIVE)
For: ClickUP Learning Platform
Format: Q&A for each syllabus topic
Level: Advanced Level (Sciences)
1. ATOMIC STRUCTURE & PERIODICITY
Q1: What is meant by the term “atomic orbital”?
An atomic orbital is a region around the nucleus where there is a high probability of finding an electron. Each orbital has a specific shape and orientation (s, p, d, f).
Q2: State the three quantum numbers and what each represents.
- n (principal quantum number): Energy level and size of orbital
- l (azimuthal quantum number): Shape of orbital
- mₗ (magnetic quantum number): Orientation of orbital
Q3: Why do elements in the same group have similar chemical properties?
They have the same number of valence electrons, resulting in similar bonding behaviour.
Q4: Explain why ionization energy increases across a period.
Nuclear charge increases while shielding remains relatively constant; electrons are held more tightly, requiring more energy to remove.
Q5: Why does atomic radius increase down a group?
Additional energy levels are added, increasing the size of the atom despite increasing nuclear charge.
2. CHEMICAL BONDING
Q1: What is a covalent bond?
A covalent bond is formed when two atoms share one or more pairs of electrons.
Q2: Why are ionic compounds usually soluble in water?
Water molecules are polar and can stabilize ions by hydration, breaking the ionic lattice.
Q3: What is hydrogen bonding? Give examples.
A strong dipole-dipole attraction between H and highly electronegative atoms (N, O, F)
Examples: Water, HF, ammonia.
Q4: Why does diamond have a high melting point?
It has a giant covalent structure where each carbon is covalently bonded to four others, making the structure extremely strong.
Q5: Explain metallic bonding.
Positively charged metal ions are surrounded by a sea of delocalized electrons, giving metals conductivity and malleability.
3. STOICHIOMETRY & CALCULATIONS
Q1: What is the mole?
The amount of substance containing 6.02 × 10²³ particles (Avogadro’s number).
Q2: How do you calculate empirical formula?
Convert masses to moles → divide by smallest mole value → multiply to whole numbers.
Q3: Define percentage purity.
Percentage purity = (mass of pure substance ÷ total mass of impure sample) × 100.
Q4: What is molar volume at RTP?
At room temperature and pressure, 1 mole = 24 dm³ of gas.
4. STATES OF MATTER & KINETIC THEORY
Q1: What is Boyle’s Law?
For a fixed mass of gas at constant temperature:
P ∝ 1/V or PV = constant
Q2: Why do real gases deviate from ideal behaviour?
Because real molecules have intermolecular forces and non-zero volumes.
Q3: What happens at the boiling point on the energy level?
Energy is used to break intermolecular forces, not increase temperature.
5. THERMODYNAMICS
Q1: Define enthalpy change of formation.
Heat change when 1 mole of a compound is formed from its elements in their standard states.
Q2: What is Hess’s Law?
The total enthalpy change of a reaction is the same regardless of the route taken.
Q3: Why are bond-breaking processes endothermic?
Energy is required to overcome attraction between particles.
6. CHEMICAL KINETICS
Q1: What is activation energy?
Minimum energy needed for reacting molecules to form products.
Q2: How does temperature affect reaction rate?
Increases frequency and energy of collisions → more particles exceed activation energy.
Q3: Why do catalysts increase reaction rate?
They provide an alternative pathway with lower activation energy.
7. CHEMICAL EQUILIBRIUM
Q1: State Le Chatelier’s Principle.
A system at equilibrium adjusts to oppose any applied change.
Q2: What happens to equilibrium when pressure is increased?
It shifts towards the side with fewer moles of gas.
Q3: What is the equilibrium constant Kc?
Kc = (product concentrations) / (reactant concentrations), each raised to stoichiometric powers.
8. ACIDS, BASES & SALTS
Q1: What is a Bronsted-Lowry acid?
A proton donor.
Q2: Why is water amphoteric?
It can act as both a proton donor and acceptor.
Q3: What is a buffer solution?
A solution that resists changes in pH when small amounts of acid or base are added.
Q4: What is hydrolysis of salts?
Reaction of salt ions with water to form acidic or basic solutions.
9. REDOX REACTIONS & ELECTROCHEMISTRY
Q1: Define oxidation in terms of electrons.
Loss of electrons.
Q2: What is a standard electrode potential?
Voltage developed when a metal is in contact with 1M of its ions under standard conditions.
Q3: Why do reactive metals have highly negative electrode potentials?
They easily lose electrons to form positive ions.
Q4: What is electrolysis?
Decomposition of an electrolyte using electric current.
10. ORGANIC CHEMISTRY
Q1: What is a homologous series?
A family of organic compounds with similar chemical properties and the same functional group.
**Q2: State the general formula of:
- Alkanes • Alkenes • Alkynes**
- Alkanes: CₙH₂ₙ₊₂
- Alkenes: CₙH₂ₙ
- Alkynes: CₙH₂ₙ₋₂
Q3: What is isomerism?
Compounds with the same molecular formula but different structural arrangements.
Q4: Why do alcohols have higher boiling points than alkanes?
Presence of hydrogen bonding.
Q5: What are nucleophiles and electrophiles?
- Nucleophiles: Electron-pair donors
- Electrophiles: Electron-pair acceptors
11. ANALYTICAL CHEMISTRY
Q1: What is chromatography?
A separation technique based on different rates of movement through a medium.
Q2: What is the Rf value?
Distance travelled by substance ÷ distance travelled by solvent.
Q3: Why is titration used?
For accurate determination of unknown concentrations.
Q4: How does a calorimeter work?
It measures heat changes during chemical reactions.
12. TRANSITION METALS
Q1: Why do transition metals form coloured ions?
Due to d–d electron transitions when light is absorbed.
Q2: Why do transition metals act as catalysts?
They can change oxidation states and provide alternative reaction pathways.
Q3: What is a complex ion?
A central metal ion surrounded by ligands bonded through coordinate bonds.
13. NUCLEAR CHEMISTRY
Q1: What is radioactive decay?
Spontaneous emission of radiation from unstable nuclei.
Q2: State the three types of radiation.
Alpha, Beta, Gamma.
Q3: What is half-life?
Time taken for half of the radioactive nuclei to decay.