In Matric Organic Chemistry (Intermolecular Forces & Physical Properties), rank the homologous series from weakest to strongest intermolecular forces and explain how this affects Boiling Point, Melting Point, and Vapour Pressure.

Order of IMF strength: Alkanes/Alkenes/Alkynes (weak London/dispersion forces) < Aldehydes/Ketones/Esters/Haloalkanes (dipole-dipole forces) < Alcohols (1 site for Hydrogen bonding) < Carboxylic Acids (strongest: 2 sites for Hydrogen bonding / dimer formation). Stronger IMFs require MORE energy to overcome, resulting in a HIGHER boiling/melting point and a LOWER vapour pressure.

In Matric Physics (Electrodynamics), compare an AC Generator (Alternator), a DC Generator (Dynamo), and an Electric Motor regarding energy conversion and commutator/ring structure.

Generators convert MECHANICAL energy into ELECTRICAL energy using Faraday's Law of Electromagnetic Induction (use Fleming's Right-Hand Dynamo Rule). An AC Generator uses two SLIP RINGS (producing alternating current), while a DC Generator uses a SPLIT-RING COMMUTATOR (producing direct current in one direction). An Electric Motor converts ELECTRICAL energy into MECHANICAL energy (uses a split-ring commutator and Fleming's Left-Hand Motor Rule).

In Matric Physics (Photoelectric Effect), how does increasing (a) the frequency of incident light (above f0) and (b) the intensity (brightness) of incident light affect the emitted photoelectrons?

(a) Increasing FREQUENCY (above threshold frequency f0) increases the energy of each photon (E = hf), which increases the MAXIMUM KINETIC ENERGY (E_k(max)) of the emitted photoelectrons (stopping potential increases, but number of electrons per second is unchanged). (b) Increasing INTENSITY (at f > f0) increases the number of photons striking the metal per second, which increases the NUMBER of photoelectrons emitted per second (ammeter reading/photocurrent increases), while E_k(max) remains unchanged.

In Matric Chemistry (Electrochemistry), compare a Galvanic (Voltaic) Cell with an Electrolytic Cell.

Galvanic cell: converts CHEMICAL energy into ELECTRICAL energy via a spontaneous redox reaction (E°_cell > 0, exothermic); Anode is NEGATIVE (oxidation) and Cathode is POSITIVE (reduction); uses two separate half-cells connected by a salt bridge. Electrolytic cell: converts ELECTRICAL energy into CHEMICAL energy via a non-spontaneous redox reaction driven by an external battery/DC source; Anode is POSITIVE (oxidation) and Cathode is NEGATIVE (reduction).

In Matric Physics, how does an airbag or seatbelt reduce injury during a car crash according to the Impulse-Momentum Theorem (F_net · Δt = Δp)?

For a given change in momentum (Δp = m(v_f - v_i) to bring the passenger to rest), the airbag/seatbelt INCREASES the contact time (Δt) over which the passenger's momentum changes. Since F_net = Δp / Δt, increasing Δt for a constant Δp DECREASES the net force (F_net) exerted on the passenger.

In Matric Physics (Doppler Effect), state the Doppler Effect and write the formula for a source moving TOWARDS a stationary listener versus AWAY from a stationary listener.

Doppler Effect: The change in frequency (or pitch) of the sound detected by a listener because the sound source and the listener have different velocities relative to the medium of sound propagation. General formula: f_L = [(v ± v_L) / (v ± v_S)] · f_S. For stationary listener (v_L = 0): Source moving TOWARDS listener uses MINUS in denominator: f_L = [v / (v - v_S)] · f_S (higher frequency); Source moving AWAY uses PLUS: f_L = [v / (v + v_S)] · f_S (lower frequency).

In Matric Physics (Doppler Effect in Astronomy & Medicine), what is Red Shift and how does it support the expanding universe, and how are Doppler flow meters used clinically?

Light from distant galaxies is shifted toward the red end of the visible spectrum (longer wavelength, lower frequency), proving by the Doppler Effect that distant galaxies are moving AWAY from Earth and the universe is expanding. In medicine, ultrasonic Doppler flow meters measure the speed and direction of blood flow in arteries or fetal heartbeat.

In Matric Electrochemistry, what are the two functions of the Salt Bridge in a Galvanic Cell, and what are the Standard Conditions for measuring standard electrode potentials (including the Standard Hydrogen Electrode - SHE)?

Salt bridge functions: 1. Completes the circuit, and 2. Maintains electrical neutrality in the half-cells by allowing migration of ions. Standard conditions: Temperature = 25°C (298 K), Electrolyte concentration = 1.0 mol·dm⁻³, and Gas pressure = 101.3 kPa (1 atm). The SHE has a reference potential of E° = 0.00 V using a platinum electrode in 1 M H⁺ with H2(g) at 101.3 kPa.

In Matric Physics (Work, Energy and Power), state the Work-Energy Theorem and define a Non-Conservative Force vs. a Conservative Force.

Work-Energy Theorem: The net (total) work done on an object is equal to the change in the object's kinetic energy (W_net = ΔE_k = E_kf - E_ki). Conservative force (e.g., gravitational force, electrostatic force): work done is independent of the path taken and mechanical energy is conserved. Non-conservative force (e.g., friction, air resistance, applied tension): work done depends on the path and changes total mechanical energy (W_nc = ΔE_k + ΔE_p).

In Matric Chemistry (Maxwell-Boltzmann Distribution Curve), how does increasing Temperature vs. adding a Catalyst alter the Maxwell-Boltzmann distribution curve of molecular kinetic energies?

Increasing Temperature flattens the peak and shifts the curve to the RIGHT (average kinetic energy increases), increasing the shaded area beyond E_a. Adding a Catalyst does NOT change the shape or peak of the curve at all—it shifts the vertical Activation Energy threshold line (E_a) to the LEFT, increasing the shaded area of particles with E ≥ E_a.

In Matric Physics (Electrostatics), state Coulomb's Law and define Electric Field at a point.

Coulomb's Law: The magnitude of the electrostatic force exerted by one point charge on another is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance (r) between their centres: F = k·Q1·Q2 / r² (where k = 9.0 × 10⁹ N·m²·C⁻²). Electric field at a point (E = F / q = kQ / r²) is the electrostatic force experienced per unit positive charge placed at that point.

In Matric Chemistry (Acids & Bases Calculations), how do you calculate pH for a diprotic strong acid like 0.05 mol·dm⁻³ H2SO4 and a strong base like 0.02 mol·dm⁻³ Ba(OH)2 at 25°C (K_w = 1.0 × 10⁻¹⁴)?

For 0.05 M H2SO4 (complete ionization gives 2 moles H3O⁺ per mole acid): [H3O⁺] = 2 × 0.05 = 0.10 mol·dm⁻³ => pH = -log(0.10) = 1.0. For 0.02 M Ba(OH)2: [OH⁻] = 2 × 0.02 = 0.04 mol·dm⁻³; [H3O⁺] = K_w / [OH⁻] = (1.0 × 10⁻¹⁴) / 0.04 = 2.5 × 10⁻¹³ M => pH = -log(2.5 × 10⁻¹³) = 12.60.

In Matric Chemistry (Acids & Bases), compare the Arrhenius and Lowry-Brønsted definitions of acids and bases, and identify the conjugate acid-base pairs in NH3 + H2O ⇌ NH4⁺ + OH⁻.

Arrhenius: Acid produces H⁺/H3O⁺ ions in aqueous solution; Base produces OH⁻ ions in aqueous solution. Lowry-Brønsted: Acid is a PROTON (H⁺) DONOR; Base is a PROTON (H⁺) ACCEPTOR. In NH3 + H2O ⇌ NH4⁺ + OH⁻, H2O (acid) donates H⁺ to form its conjugate base OH⁻; NH3 (base) accepts H⁺ to form its conjugate acid NH4⁺. Substances that can act as either an acid or a base (like H2O, HCO3⁻, HSO4⁻) are ampholytes (amphoteric).

In Matric Physics (Alternating Current), write the formulas for Root-Mean-Square Voltage (V_rms), RMS Current (I_rms), and Average Power (P_ave), and state why AC is preferred over DC for long-distance power transmission.

V_rms = V_max / √2; I_rms = I_max / √2; P_ave = V_rms · I_rms = ½ V_max · I_max. AC is preferred because transformers can step up AC voltage to very high values, which reduces the transmission current (I) for a given power (P = VI), thereby minimizing power dissipated as heat in transmission cables (P_loss = I²R).

In Matric Physics (Free-Body vs Force Diagrams), what is the critical DBE marking rule for drawing a Free-Body Diagram on an inclined plane?

Represent the object as a single dot; draw all forces as arrows pointing AWAY from the dot; never draw BOTH a force (like gravitational force w / F_g) AND its components (F_g|| and F_g⊥) on the same diagram (that loses marks for double-counting); and ensure the Normal force (N) is drawn strictly perpendicular to the surface, not vertically upwards.

In Matric Physics (Spectra), distinguish between an Atomic Absorption Spectrum and an Atomic Emission Line Spectrum.

An Atomic Emission Line Spectrum consists of discrete bright coloured lines on a dark background, produced when excited electrons transition from higher energy levels to lower energy levels and emit photons of specific energy (ΔE = E_high - E_low = hf). An Atomic Absorption Spectrum is a continuous spectrum crossed by dark absorption lines, produced when white light passes through a cool gas and electrons absorb photons of exact frequencies to jump to higher energy levels.

In NSC Matric Physical Sciences Paper 2 (Organic Chemistry), list the 9 homologous series tested in CAPS along with their functional groups.

1. Alkanes (only C-C single bonds), 2. Alkenes (C=C double bond), 3. Alkynes (C≡C triple bond), 4. Haloalkanes/Alkyl halides (-X where X = F, Cl, Br, I), 5. Alcohols (-OH hydroxyl group), 6. Aldehydes (-CHO formyl/terminal carbonyl), 7. Ketones (-CO- internal carbonyl), 8. Carboxylic acids (-COOH carboxyl group), 9. Esters (-COO- ester link).

In Matric Electrochemistry (Industrial Electrolysis), compare the electrolysis of Concentrated NaCl (Brine) in the Chlor-Alkali industry with Electrorefining of Copper.

In the Chlor-Alkali membrane cell (electrolysis of saturated NaCl brine): at the Anode, Cl⁻ is oxidized to Chlorine gas (2Cl⁻ -> Cl2 + 2e⁻); at the Cathode, water is reduced to Hydrogen gas and hydroxide ions (2H2O + 2e⁻ -> H2 + 2OH⁻), producing pure NaOH(aq) (because H2O is a stronger oxidizing agent than Na⁺). In Electrorefining of Copper: impure blister copper is the Anode (Cu -> Cu²⁺ + 2e⁻) and pure copper is deposited at the Cathode (Cu²⁺ + 2e⁻ -> Cu), while precious metals (Ag, Au, Pt) sink as anode sludge.

In Matric Organic Chemistry, how do Chain Length and Branching affect the boiling point of alkanes (structural isomers like pentane, 2-methylbutane, and 2,2-dimethylpropane)?

Increasing chain length (molar mass/surface area) increases the strength of London forces and raises the boiling point. Increasing BRANCHING makes the molecule more spherical/compact, decreasing surface area of contact, weakening London forces, and LOWERING the boiling point (and raising vapour pressure).

In Matric Organic Chemistry, distinguish the reaction conditions for converting a Haloalkane to an Alcohol (Hydrolysis/Substitution) versus converting a Haloalkane to an Alkene (Dehydrohalogenation/Elimination).

Substitution (Haloalkane -> Alcohol): use DILUTE strong base (aq. NaOH/KOH) in water/mild heat (or warm water in ethanol). Elimination (Haloalkane -> Alkene + HX): use CONCENTRATED strong base (conc. NaOH/KOH) dissolved in pure ETHANOL under strong heat/reflux (no water present).

In Matric Physics (Vertical Projectile Motion), what is the magnitude and direction of the acceleration of a free-falling object throughout its upward motion, at its maximum height, and during its downward motion?

Throughout the entire free-fall trajectory—moving upward, momentarily at rest at maximum height (v = 0 m/s), and moving downward—the acceleration is constantly 9.8 m·s⁻² DOWNWARDS (g = 9.8 m·s⁻² downwards).

In Matric Physics (Graphs of Projectile Motion), if upward is chosen as positive, what do the Position-Time (y vs t), Velocity-Time (v vs t), and Acceleration-Time (a vs t) graphs look like for a ball thrown vertically upwards and caught at the same height?

Position-Time (y vs t): concave-down parabola starting and ending at y = 0, peaking at t_max. Velocity-Time (v vs t): straight line with constant negative gradient (-9.8 m·s⁻²), starting at +v_i, crossing the time axis (v = 0) at maximum height, and ending at -v_i. Acceleration-Time (a vs t): horizontal straight line at a = -9.8 m·s⁻².

In Matric Physics, state the Principle of Conservation of Linear Momentum and distinguish between an Elastic Collision and an Inelastic Collision.

Conservation of Linear Momentum: The total linear momentum of an isolated system remains constant in magnitude and direction (Σp_before = Σp_after, provided no external net force acts). In an Elastic collision, BOTH total linear momentum and total kinetic energy are conserved (ΣE_k(before) = ΣE_k(after)); in an Inelastic collision, total linear momentum is conserved, but total kinetic energy is NOT conserved.

In Matric Chemistry (Chemical Equilibrium), in the reaction 2SO2(g) + O2(g) ⇌ 2SO3(g) (ΔH < 0, exothermic), how does (a) increasing temperature and (b) decreasing container volume (increasing pressure) affect the yield of SO3 and K_c?

(a) Increasing temperature favours the endothermic reaction (reverse reaction); equilibrium shifts to the left, SO3 yield decreases, and K_c decreases. (b) Decreasing volume increases pressure, which favours the side with fewer moles of gas (forward reaction: 3 moles gas -> 2 moles gas); SO3 yield increases, while K_c remains unchanged.

In Matric Chemistry (Reaction Rates & Energy), state the Collision Theory and explain how a Catalyst increases the rate of both forward and reverse reactions.

Collision Theory: Particles must collide with both (1) correct orientation and (2) sufficient kinetic energy greater than or equal to the activation energy (E ≥ E_a). A catalyst provides an alternative reaction pathway with a LOWER activation energy (E_a), so more particles have E ≥ E_a, increasing the number of effective collisions per unit time (without changing ΔH).

In Matric Chemistry (Salt Hydrolysis), predict whether aqueous solutions of NH4Cl, CH3COONa (or Na2CO3), and NaCl are acidic, basic, or neutral, with hydrolysis equations.

NH4Cl (strong acid HCl + weak base NH3) is ACIDIC (pH 7) because CH3COO⁻ hydrolyzes: CH3COO⁻ + H2O ⇌ CH3COOH + OH⁻. NaCl (strong acid + strong base) is NEUTRAL (pH = 7).

In NSC Matric Physical Sciences Paper 1 (Physics), state Newton's Second Law of Motion in terms of both acceleration and momentum.

In terms of acceleration: When a net force acts on an object, the object accelerates in the direction of the net force; the acceleration is directly proportional to the net force and inversely proportional to the mass of the object (F_net = ma). In terms of momentum: The net (resultant) force acting on an object is equal to the rate of change of momentum of the object (F_net = Δp / Δt).

In Matric Organic Chemistry (Reactions), state Markovnikov's Rule for Addition Reactions (hydrohalogenation/hydration of unsymmetrical alkenes) and Zaitsev's Rule for Elimination Reactions (dehydrohalogenation/dehydration).

Markovnikov's Rule (Addition to unsymmetrical alkene): The hydrogen atom (H) adds to the carbon atom of the double bond that ALREADY has the greater number of hydrogen atoms ('the rich get richer'), while the halide/OH adds to the more substituted carbon. Zaitsev's Rule (Elimination from haloalkane/alcohol): The hydrogen atom is removed from the adjacent carbon atom that has the FEWEST hydrogen atoms ('the poor get poorer') to form the more substituted major alkene.

In Matric Electrochemistry, how is the standard cell emf (E°_cell) calculated, and how do you write standard Cell Notation for Zn(s) | Zn²⁺(aq) || Cu²⁺(aq) | Cu(s)?

E°_cell = E°_cathode (reduction) - E°_anode (oxidation). In cell notation, the Anode (oxidation) is always written on the LEFT, separated by a double vertical line || (salt bridge) from the Cathode (reduction) on the RIGHT: Zn(s) | Zn²⁺(1 mol·dm⁻³) || Cu²⁺(1 mol·dm⁻³) | Cu(s). Here E°_cell = (+0.34 V) - (-0.76 V) = +1.10 V.

In Matric Physics (Electric Circuits), define Electromotive Force (emf) and Internal Resistance (r), and explain why the terminal potential difference (V_load) drops when a switch is closed or resistance decreases.

Emf (ε) is the maximum energy provided by a battery per unit charge passing through it (measured when no current flows). By ε = V_ext + V_internal = I(R + r), when current I increases (due to decreased external resistance R), the 'lost volts' across the internal resistance (V_internal = Ir) increase; since ε is constant, the terminal potential difference V_ext = ε - Ir decreases.

In Matric Chemistry (Chemical Equilibrium), state Le Chatelier's Principle and write the template for answering Equilibrium Shift questions.

Le Chatelier's Principle: When the equilibrium in a closed system is disturbed by changing the conditions (concentration, pressure/volume, or temperature), the system will reinstate a new equilibrium by favouring the reaction that opposes the disturbance. Note: ONLY a change in TEMPERATURE changes the value of the equilibrium constant (K_c).

In Matric Chemistry (Esters), what are the IUPAC name and structural origin of the ester formed when Methanol reacts with Propanoic acid in the presence of concentrated H2SO4?

Methyl propanoate (CH3CH2COOCH3) + H2O. The first part of an ester's name ('methyl') comes from the alcohol (methanol), and the '-oate' part ('propanoate') comes from the carboxylic acid (propanoic acid). Concentrated H2SO4 acts both as a catalyst and as a dehydrating agent (removing water to shift equilibrium toward ester formation).

South Africa NSC Matric Physical Sciences (Physics & Chemistry): Newton's Laws, Work-Energy, Doppler Effect, Electrodynamics, Organic Chemistry & Equilibrium

Covers South Africa CAPS Grade 12 NSC Matric Physical Sciences Paper 1 (Physics: Newton's Laws, Momentum/Impulse, Vertical Projectile Motion, Work-Energy Theorem, Doppler Effect, Electrostatics, Electric Circuits, Electrodynamics, Photoelectric Effect) & Paper 2 (Chemistry: Organic Chemistry, Rates, Chemical Equilibrium, Acids/Bases, Electrochemistry).

Level: basic
Languages: en → en
Cards: 32
Markdown: South Africa NSC Matric Physical Sciences (Physics & Chemistry): Newton's Laws, Work-Energy, Doppler Effect, Electrodynamics, Organic Chemistry & Equilibrium (.md)

Flashcards (32)

#	Front (Term / Question)	Back (Definition / Answer)
1	In Matric Organic Chemistry (Intermolecular Forces & Physical Properties), rank the homologous series from weakest to strongest intermolecular forces and explain how this affects Boiling Point, Melting Point, and Vapour Pressure.	Order of IMF strength: Alkanes/Alkenes/Alkynes (weak London/dispersion forces) < Aldehydes/Ketones/Esters/Haloalkanes (dipole-dipole forces) < Alcohols (1 site for Hydrogen bonding) < Carboxylic Acids (strongest: 2 sites for Hydrogen bonding / dimer formation). Stronger IMFs require MORE energy to overcome, resulting in a HIGHER boiling/melting point and a LOWER vapour pressure.
2	In Matric Physics (Electrodynamics), compare an AC Generator (Alternator), a DC Generator (Dynamo), and an Electric Motor regarding energy conversion and commutator/ring structure.	Generators convert MECHANICAL energy into ELECTRICAL energy using Faraday's Law of Electromagnetic Induction (use Fleming's Right-Hand Dynamo Rule). An AC Generator uses two SLIP RINGS (producing alternating current), while a DC Generator uses a SPLIT-RING COMMUTATOR (producing direct current in one direction). An Electric Motor converts ELECTRICAL energy into MECHANICAL energy (uses a split-ring commutator and Fleming's Left-Hand Motor Rule).
3	In Matric Physics (Photoelectric Effect), how does increasing (a) the frequency of incident light (above f0) and (b) the intensity (brightness) of incident light affect the emitted photoelectrons?	(a) Increasing FREQUENCY (above threshold frequency f0) increases the energy of each photon (E = hf), which increases the MAXIMUM KINETIC ENERGY (E_k(max)) of the emitted photoelectrons (stopping potential increases, but number of electrons per second is unchanged). (b) Increasing INTENSITY (at f > f0) increases the number of photons striking the metal per second, which increases the NUMBER of photoelectrons emitted per second (ammeter reading/photocurrent increases), while E_k(max) remains unchanged.
4	In Matric Chemistry (Electrochemistry), compare a Galvanic (Voltaic) Cell with an Electrolytic Cell.	Galvanic cell: converts CHEMICAL energy into ELECTRICAL energy via a spontaneous redox reaction (E°_cell > 0, exothermic); Anode is NEGATIVE (oxidation) and Cathode is POSITIVE (reduction); uses two separate half-cells connected by a salt bridge. Electrolytic cell: converts ELECTRICAL energy into CHEMICAL energy via a non-spontaneous redox reaction driven by an external battery/DC source; Anode is POSITIVE (oxidation) and Cathode is NEGATIVE (reduction).
5	In Matric Physics, how does an airbag or seatbelt reduce injury during a car crash according to the Impulse-Momentum Theorem (F_net · Δt = Δp)?	For a given change in momentum (Δp = m(v_f - v_i) to bring the passenger to rest), the airbag/seatbelt INCREASES the contact time (Δt) over which the passenger's momentum changes. Since F_net = Δp / Δt, increasing Δt for a constant Δp DECREASES the net force (F_net) exerted on the passenger.
6	In Matric Physics (Doppler Effect), state the Doppler Effect and write the formula for a source moving TOWARDS a stationary listener versus AWAY from a stationary listener.	Doppler Effect: The change in frequency (or pitch) of the sound detected by a listener because the sound source and the listener have different velocities relative to the medium of sound propagation. General formula: f_L = [(v ± v_L) / (v ± v_S)] · f_S. For stationary listener (v_L = 0): Source moving TOWARDS listener uses MINUS in denominator: f_L = [v / (v - v_S)] · f_S (higher frequency); Source moving AWAY uses PLUS: f_L = [v / (v + v_S)] · f_S (lower frequency).
7	In Matric Physics (Doppler Effect in Astronomy & Medicine), what is Red Shift and how does it support the expanding universe, and how are Doppler flow meters used clinically?	Light from distant galaxies is shifted toward the red end of the visible spectrum (longer wavelength, lower frequency), proving by the Doppler Effect that distant galaxies are moving AWAY from Earth and the universe is expanding. In medicine, ultrasonic Doppler flow meters measure the speed and direction of blood flow in arteries or fetal heartbeat.
8	In Matric Electrochemistry, what are the two functions of the Salt Bridge in a Galvanic Cell, and what are the Standard Conditions for measuring standard electrode potentials (including the Standard Hydrogen Electrode - SHE)?	Salt bridge functions: 1. Completes the circuit, and 2. Maintains electrical neutrality in the half-cells by allowing migration of ions. Standard conditions: Temperature = 25°C (298 K), Electrolyte concentration = 1.0 mol·dm⁻³, and Gas pressure = 101.3 kPa (1 atm). The SHE has a reference potential of E° = 0.00 V using a platinum electrode in 1 M H⁺ with H2(g) at 101.3 kPa.
9	In Matric Physics (Work, Energy and Power), state the Work-Energy Theorem and define a Non-Conservative Force vs. a Conservative Force.	Work-Energy Theorem: The net (total) work done on an object is equal to the change in the object's kinetic energy (W_net = ΔE_k = E_kf - E_ki). Conservative force (e.g., gravitational force, electrostatic force): work done is independent of the path taken and mechanical energy is conserved. Non-conservative force (e.g., friction, air resistance, applied tension): work done depends on the path and changes total mechanical energy (W_nc = ΔE_k + ΔE_p).
10	In Matric Chemistry (Maxwell-Boltzmann Distribution Curve), how does increasing Temperature vs. adding a Catalyst alter the Maxwell-Boltzmann distribution curve of molecular kinetic energies?	Increasing Temperature flattens the peak and shifts the curve to the RIGHT (average kinetic energy increases), increasing the shaded area beyond E_a. Adding a Catalyst does NOT change the shape or peak of the curve at all—it shifts the vertical Activation Energy threshold line (E_a) to the LEFT, increasing the shaded area of particles with E ≥ E_a.
11	In Matric Physics (Electrostatics), state Coulomb's Law and define Electric Field at a point.	Coulomb's Law: The magnitude of the electrostatic force exerted by one point charge on another is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance (r) between their centres: F = k·Q1·Q2 / r² (where k = 9.0 × 10⁹ N·m²·C⁻²). Electric field at a point (E = F / q = kQ / r²) is the electrostatic force experienced per unit positive charge placed at that point.
12	In Matric Chemistry (Acids & Bases Calculations), how do you calculate pH for a diprotic strong acid like 0.05 mol·dm⁻³ H2SO4 and a strong base like 0.02 mol·dm⁻³ Ba(OH)2 at 25°C (K_w = 1.0 × 10⁻¹⁴)?	For 0.05 M H2SO4 (complete ionization gives 2 moles H3O⁺ per mole acid): [H3O⁺] = 2 × 0.05 = 0.10 mol·dm⁻³ => pH = -log(0.10) = 1.0. For 0.02 M Ba(OH)2: [OH⁻] = 2 × 0.02 = 0.04 mol·dm⁻³; [H3O⁺] = K_w / [OH⁻] = (1.0 × 10⁻¹⁴) / 0.04 = 2.5 × 10⁻¹³ M => pH = -log(2.5 × 10⁻¹³) = 12.60.
13	In Matric Chemistry (Acids & Bases), compare the Arrhenius and Lowry-Brønsted definitions of acids and bases, and identify the conjugate acid-base pairs in NH3 + H2O ⇌ NH4⁺ + OH⁻.	Arrhenius: Acid produces H⁺/H3O⁺ ions in aqueous solution; Base produces OH⁻ ions in aqueous solution. Lowry-Brønsted: Acid is a PROTON (H⁺) DONOR; Base is a PROTON (H⁺) ACCEPTOR. In NH3 + H2O ⇌ NH4⁺ + OH⁻, H2O (acid) donates H⁺ to form its conjugate base OH⁻; NH3 (base) accepts H⁺ to form its conjugate acid NH4⁺. Substances that can act as either an acid or a base (like H2O, HCO3⁻, HSO4⁻) are ampholytes (amphoteric).
14	In Matric Physics (Alternating Current), write the formulas for Root-Mean-Square Voltage (V_rms), RMS Current (I_rms), and Average Power (P_ave), and state why AC is preferred over DC for long-distance power transmission.	V_rms = V_max / √2; I_rms = I_max / √2; P_ave = V_rms · I_rms = ½ V_max · I_max. AC is preferred because transformers can step up AC voltage to very high values, which reduces the transmission current (I) for a given power (P = VI), thereby minimizing power dissipated as heat in transmission cables (P_loss = I²R).
15	In Matric Physics (Free-Body vs Force Diagrams), what is the critical DBE marking rule for drawing a Free-Body Diagram on an inclined plane?	Represent the object as a single dot; draw all forces as arrows pointing AWAY from the dot; never draw BOTH a force (like gravitational force w / F_g) AND its components (F_g\|\| and F_g⊥) on the same diagram (that loses marks for double-counting); and ensure the Normal force (N) is drawn strictly perpendicular to the surface, not vertically upwards.
16	In Matric Physics (Spectra), distinguish between an Atomic Absorption Spectrum and an Atomic Emission Line Spectrum.	An Atomic Emission Line Spectrum consists of discrete bright coloured lines on a dark background, produced when excited electrons transition from higher energy levels to lower energy levels and emit photons of specific energy (ΔE = E_high - E_low = hf). An Atomic Absorption Spectrum is a continuous spectrum crossed by dark absorption lines, produced when white light passes through a cool gas and electrons absorb photons of exact frequencies to jump to higher energy levels.
17	In NSC Matric Physical Sciences Paper 2 (Organic Chemistry), list the 9 homologous series tested in CAPS along with their functional groups.	1. Alkanes (only C-C single bonds), 2. Alkenes (C=C double bond), 3. Alkynes (C≡C triple bond), 4. Haloalkanes/Alkyl halides (-X where X = F, Cl, Br, I), 5. Alcohols (-OH hydroxyl group), 6. Aldehydes (-CHO formyl/terminal carbonyl), 7. Ketones (-CO- internal carbonyl), 8. Carboxylic acids (-COOH carboxyl group), 9. Esters (-COO- ester link).
18	In Matric Electrochemistry (Industrial Electrolysis), compare the electrolysis of Concentrated NaCl (Brine) in the Chlor-Alkali industry with Electrorefining of Copper.	In the Chlor-Alkali membrane cell (electrolysis of saturated NaCl brine): at the Anode, Cl⁻ is oxidized to Chlorine gas (2Cl⁻ -> Cl2 + 2e⁻); at the Cathode, water is reduced to Hydrogen gas and hydroxide ions (2H2O + 2e⁻ -> H2 + 2OH⁻), producing pure NaOH(aq) (because H2O is a stronger oxidizing agent than Na⁺). In Electrorefining of Copper: impure blister copper is the Anode (Cu -> Cu²⁺ + 2e⁻) and pure copper is deposited at the Cathode (Cu²⁺ + 2e⁻ -> Cu), while precious metals (Ag, Au, Pt) sink as anode sludge.
19	In Matric Organic Chemistry, how do Chain Length and Branching affect the boiling point of alkanes (structural isomers like pentane, 2-methylbutane, and 2,2-dimethylpropane)?	Increasing chain length (molar mass/surface area) increases the strength of London forces and raises the boiling point. Increasing BRANCHING makes the molecule more spherical/compact, decreasing surface area of contact, weakening London forces, and LOWERING the boiling point (and raising vapour pressure).
20	In Matric Organic Chemistry, distinguish the reaction conditions for converting a Haloalkane to an Alcohol (Hydrolysis/Substitution) versus converting a Haloalkane to an Alkene (Dehydrohalogenation/Elimination).	Substitution (Haloalkane -> Alcohol): use DILUTE strong base (aq. NaOH/KOH) in water/mild heat (or warm water in ethanol). Elimination (Haloalkane -> Alkene + HX): use CONCENTRATED strong base (conc. NaOH/KOH) dissolved in pure ETHANOL under strong heat/reflux (no water present).
21	In Matric Physics (Vertical Projectile Motion), what is the magnitude and direction of the acceleration of a free-falling object throughout its upward motion, at its maximum height, and during its downward motion?	Throughout the entire free-fall trajectory—moving upward, momentarily at rest at maximum height (v = 0 m/s), and moving downward—the acceleration is constantly 9.8 m·s⁻² DOWNWARDS (g = 9.8 m·s⁻² downwards).
22	In Matric Physics (Graphs of Projectile Motion), if upward is chosen as positive, what do the Position-Time (y vs t), Velocity-Time (v vs t), and Acceleration-Time (a vs t) graphs look like for a ball thrown vertically upwards and caught at the same height?	Position-Time (y vs t): concave-down parabola starting and ending at y = 0, peaking at t_max. Velocity-Time (v vs t): straight line with constant negative gradient (-9.8 m·s⁻²), starting at +v_i, crossing the time axis (v = 0) at maximum height, and ending at -v_i. Acceleration-Time (a vs t): horizontal straight line at a = -9.8 m·s⁻².
23	In Matric Physics, state the Principle of Conservation of Linear Momentum and distinguish between an Elastic Collision and an Inelastic Collision.	Conservation of Linear Momentum: The total linear momentum of an isolated system remains constant in magnitude and direction (Σp_before = Σp_after, provided no external net force acts). In an Elastic collision, BOTH total linear momentum and total kinetic energy are conserved (ΣE_k(before) = ΣE_k(after)); in an Inelastic collision, total linear momentum is conserved, but total kinetic energy is NOT conserved.
24	In Matric Chemistry (Chemical Equilibrium), in the reaction 2SO2(g) + O2(g) ⇌ 2SO3(g) (ΔH < 0, exothermic), how does (a) increasing temperature and (b) decreasing container volume (increasing pressure) affect the yield of SO3 and K_c?	(a) Increasing temperature favours the endothermic reaction (reverse reaction); equilibrium shifts to the left, SO3 yield decreases, and K_c decreases. (b) Decreasing volume increases pressure, which favours the side with fewer moles of gas (forward reaction: 3 moles gas -> 2 moles gas); SO3 yield increases, while K_c remains unchanged.
25	In Matric Chemistry (Reaction Rates & Energy), state the Collision Theory and explain how a Catalyst increases the rate of both forward and reverse reactions.	Collision Theory: Particles must collide with both (1) correct orientation and (2) sufficient kinetic energy greater than or equal to the activation energy (E ≥ E_a). A catalyst provides an alternative reaction pathway with a LOWER activation energy (E_a), so more particles have E ≥ E_a, increasing the number of effective collisions per unit time (without changing ΔH).
26	In Matric Chemistry (Salt Hydrolysis), predict whether aqueous solutions of NH4Cl, CH3COONa (or Na2CO3), and NaCl are acidic, basic, or neutral, with hydrolysis equations.	NH4Cl (strong acid HCl + weak base NH3) is ACIDIC (pH < 7) because NH4⁺ hydrolyzes: NH4⁺ + H2O ⇌ NH3 + H3O⁺. CH3COONa (weak acid CH3COOH + strong base NaOH) is BASIC (pH > 7) because CH3COO⁻ hydrolyzes: CH3COO⁻ + H2O ⇌ CH3COOH + OH⁻. NaCl (strong acid + strong base) is NEUTRAL (pH = 7).
27	In NSC Matric Physical Sciences Paper 1 (Physics), state Newton's Second Law of Motion in terms of both acceleration and momentum.	In terms of acceleration: When a net force acts on an object, the object accelerates in the direction of the net force; the acceleration is directly proportional to the net force and inversely proportional to the mass of the object (F_net = ma). In terms of momentum: The net (resultant) force acting on an object is equal to the rate of change of momentum of the object (F_net = Δp / Δt).
28	In Matric Organic Chemistry (Reactions), state Markovnikov's Rule for Addition Reactions (hydrohalogenation/hydration of unsymmetrical alkenes) and Zaitsev's Rule for Elimination Reactions (dehydrohalogenation/dehydration).	Markovnikov's Rule (Addition to unsymmetrical alkene): The hydrogen atom (H) adds to the carbon atom of the double bond that ALREADY has the greater number of hydrogen atoms ('the rich get richer'), while the halide/OH adds to the more substituted carbon. Zaitsev's Rule (Elimination from haloalkane/alcohol): The hydrogen atom is removed from the adjacent carbon atom that has the FEWEST hydrogen atoms ('the poor get poorer') to form the more substituted major alkene.
29	In Matric Electrochemistry, how is the standard cell emf (E°_cell) calculated, and how do you write standard Cell Notation for Zn(s) \| Zn²⁺(aq) \|\| Cu²⁺(aq) \| Cu(s)?	E°_cell = E°_cathode (reduction) - E°_anode (oxidation). In cell notation, the Anode (oxidation) is always written on the LEFT, separated by a double vertical line \|\| (salt bridge) from the Cathode (reduction) on the RIGHT: Zn(s) \| Zn²⁺(1 mol·dm⁻³) \|\| Cu²⁺(1 mol·dm⁻³) \| Cu(s). Here E°_cell = (+0.34 V) - (-0.76 V) = +1.10 V.
30	In Matric Physics (Electric Circuits), define Electromotive Force (emf) and Internal Resistance (r), and explain why the terminal potential difference (V_load) drops when a switch is closed or resistance decreases.	Emf (ε) is the maximum energy provided by a battery per unit charge passing through it (measured when no current flows). By ε = V_ext + V_internal = I(R + r), when current I increases (due to decreased external resistance R), the 'lost volts' across the internal resistance (V_internal = Ir) increase; since ε is constant, the terminal potential difference V_ext = ε - Ir decreases.
31	In Matric Chemistry (Chemical Equilibrium), state Le Chatelier's Principle and write the template for answering Equilibrium Shift questions.	Le Chatelier's Principle: When the equilibrium in a closed system is disturbed by changing the conditions (concentration, pressure/volume, or temperature), the system will reinstate a new equilibrium by favouring the reaction that opposes the disturbance. Note: ONLY a change in TEMPERATURE changes the value of the equilibrium constant (K_c).
32	In Matric Chemistry (Esters), what are the IUPAC name and structural origin of the ester formed when Methanol reacts with Propanoic acid in the presence of concentrated H2SO4?	Methyl propanoate (CH3CH2COOCH3) + H2O. The first part of an ester's name ('methyl') comes from the alcohol (methanol), and the '-oate' part ('propanoate') comes from the carboxylic acid (propanoic acid). Concentrated H2SO4 acts both as a catalyst and as a dehydrating agent (removing water to shift equilibrium toward ester formation).