In JAMB/WAEC Acid-Base Titration, which indicator is suitable for: (a) Strong Acid + Strong Base, (b) Strong Acid + Weak Base, and (c) Weak Acid + Strong Base?

(a) Strong Acid + Strong Base (e.g., HCl + NaOH): Any indicator (Methyl orange or Phenolphthalein); (b) Strong Acid + Weak Base (e.g., HCl + NH3/Na2CO3): Methyl orange; (c) Weak Acid + Strong Base (e.g., CH3COOH or H2C2O4 + NaOH): Phenolphthalein.

In JAMB/WAEC Sound Waves (Pipes & Strings), what are the fundamental frequency (f0) and harmonics produced by a Closed Pipe of length L versus an Open Pipe or Stretched String of length L?

Closed pipe (node at closed end, antinode at open end, L = λ/4): f0 = v / (4L), producing ONLY odd harmonics (f0, 3f0, 5f0...). Open pipe or stretched string (L = λ/2): f0 = v / (2L), producing ALL harmonics—both odd and even (f0, 2f0, 3f0...).

In JAMB/WAEC Waves, what is the fundamental wave equation, and which wave properties distinguish Longitudinal waves from Transverse waves?

Wave speed v = fλ (where f is frequency in Hz and λ is wavelength in m). Only Transverse waves (light, electromagnetic waves, water/string waves) can be POLARIZED because their vibrations are perpendicular to the direction of wave propagation; Longitudinal waves (sound waves) vibrate parallel to propagation and cannot be polarized.

In JAMB/WAEC Thermal Physics, distinguish between Specific Heat Capacity (c) and Specific Latent Heat (L), and calculate the heat required to melt 0.5 kg of ice at 0°C (L_f = 3.36 × 10⁵ J/kg).

Specific heat capacity (Q = mcΔθ) is the heat required to raise the temperature of 1 kg of a substance by 1 K (with temperature change, no phase change). Specific latent heat (Q = mL) is the heat required to change the state of 1 kg of a substance at constant temperature. For 0.5 kg of ice: Q = mL_f = 0.5 × 3.36 × 10⁵ = 1.68 × 10⁵ J (168 kJ).

In JAMB/WAEC Electromagnetism, state the Transformer Voltage/Turns Ratio equation and list the 4 causes of energy loss in a practical transformer with their remedies.

Transformer equation: E_s / E_p = N_s / N_p = I_p / I_s (for 100% ideal transformer). Four energy losses & remedies: 1. Eddy currents -> Laminated soft-iron core; 2. Hysteresis loss -> Soft-iron core (easily magnetized/demagnetized); 3. Copper (I²R Joule heating) loss -> Thick low-resistance copper windings; 4. Flux leakage -> Winding secondary coils over primary on a closed core.

In JAMB/WAEC Stoichiometry, what volume does 1 mole of any ideal gas occupy at Standard Temperature and Pressure (STP: 0°C / 273 K and 1 atm / 760 mmHg), and what is Avogadro's constant?

Molar volume at STP = 22.4 dm³ (22,400 cm³); Avogadro's constant (NA) = 6.02 × 10²³ particles per mole.

In JAMB/WAEC Electrolysis, what factors determine the preferential discharge of ions at the electrodes during electrolysis of aqueous solutions?

1. Position of the ion in the Electrochemical Series (lower cations/anions are discharged first), 2. Concentration of the ions (high concentration of halide ion like Cl⁻ in brine overrides OH⁻), and 3. Nature of the electrode (e.g., mercury cathode discharges Na⁺ in the Castner-Kellner cell; reactive copper anode dissolves instead of discharging anions).

In JAMB/WAEC Optics, state the Mirror/Lens Equation and Snell's Law of Refraction, and state the two conditions required for Total Internal Reflection (TIR).

Mirror/Lens equation: 1/f = 1/u + 1/v (Magnification M = v/u = h_i/h_o). Snell's Law: n = sin i / sin r = real depth / apparent depth = 1 / sin C (where C is the critical angle). Conditions for TIR: 1. Light must travel from an optically denser medium to an optically less dense medium, and 2. The angle of incidence in the denser medium must exceed the critical angle (i > C).

In JAMB/WAEC Radioactivity, if a radioactive isotope has a half-life (T_1/2) of 5 days, what fraction and mass of an initial 80 g sample remain undecayed after 20 days?

Number of half-lives n = 20 / 5 = 4 half-lives. Remaining fraction = (1/2)^n = (1/2)⁴ = 1/16. Remaining undecayed mass = 80 g / 16 = 5 g (meaning 75 g has decayed).

In JAMB/WAEC Atomic & Quantum Physics, state Einstein's Photoelectric Equation and define Work Function (W0) and Threshold Frequency (f0).

Einstein's Photoelectric Equation: E = hf = W0 + K_max (where hf = hf0 + ½mv_max²). Work function W0 = hf0 is the minimum energy required to liberate a photoelectron from a metal surface; Threshold frequency f0 is the minimum frequency of incident radiation below which no photoelectric emission occurs regardless of intensity.

In JAMB/WAEC Chemical Equilibrium (Le Chatelier's Principle), in the exothermic Haber Process N2(g) + 3H2(g) ⇌ 2NH3(g) (ΔH = -92 kJ/mol), what conditions maximize the yield of ammonia, and what catalyst is used?

High pressure (200–250 atm, since forward reaction reduces moles from 4 to 2), moderate temperature (~450°C—low enough to favor exothermic forward yield, high enough for reaction rate), finely divided Iron (Fe) catalyst with Al2O3 promoter, and continuous removal of NH3.

In JAMB/WAEC Mechanics (Elasticity), state Hooke's Law and give the formula for elastic potential energy stored in a stretched spring or wire.

Hooke's Law states that provided the elastic limit is not exceeded, the extension (e) of an elastic material is directly proportional to the applied force/load (F = ke). Elastic potential energy stored E = ½ Fe = ½ ke².

In JAMB/WAEC Mechanics (Simple Machines), how are Mechanical Advantage (MA), Velocity Ratio (VR), and Efficiency (η) related, and what is the VR of an inclined plane of angle θ and a block-and-tackle pulley system with n pulleys?

Efficiency η = (MA / VR) × 100%, where MA = Load / Effort and VR = Distance moved by Effort / Distance moved by Load. For an inclined plane, VR = 1 / sin θ; for a block-and-tackle pulley system with n pulleys, VR = n.

In JAMB/WAEC Organic Chemistry, what reagents distinguish saturated Alkanes from unsaturated Alkenes and terminal Alkynes?

Unsaturated alkenes and alkynes decolourize reddish-brown Bromine water (Br2/CCl4) and purple acidified KMnO4 (Baeyer's reagent), whereas alkanes do not. Terminal alkynes (containing -C≡C-H) additionally react with ammoniacal Copper(I) chloride to give a reddish-brown precipitate and with ammoniacal Silver trioxonitrate(V) (Tollens' reagent) to give a white/yellow-white precipitate; alkenes do not.

In JAMB/WAEC Gas Laws, state Graham's Law of Diffusion and calculate the relative rate of diffusion of Hydrogen gas (M = 2) compared to Oxygen gas (M = 32).

Graham's Law states that at constant temperature and pressure, the rate of diffusion of a gas is inversely proportional to the square root of its vapour density or molar mass: R1/R2 = √(M2/M1). For H2 and O2: R(H2)/R(O2) = √(32/2) = √16 = 4 (Hydrogen diffuses 4 times faster than Oxygen).

In JAMB/WAEC Qualitative Analysis, how do you test for and distinguish between Iron(II) (Fe²⁺), Iron(III) (Fe³⁺), Copper(II) (Cu²⁺), and Zinc (Zn²⁺) ions using NaOH(aq) and NH3(aq)?

Fe²⁺: dirty-green gelatinous precipitate insoluble in excess NaOH and NH3; Fe³⁺: reddish-brown precipitate insoluble in excess NaOH and NH3; Cu²⁺: pale blue precipitate insoluble in excess NaOH, but dissolves in excess NH3 to form a deep blue solution; Zn²⁺: white gelatinous precipitate soluble in BOTH excess NaOH and excess NH3.

In JAMB/WAEC Alternating Current (AC) Circuits, what is the Impedance (Z) of a series R-L-C circuit, and what is the condition for Resonance?

Impedance Z = √[R² + (X_L - X_C)²], where Inductive reactance X_L = 2πfL and Capacitive reactance X_C = 1 / (2πfC). Resonance occurs when X_L = X_C, making impedance minimum (Z = R), current maximum, and resonant frequency f0 = 1 / [2π√(LC)].

In JAMB/WAEC Radioactivity, how do Alpha (α) decay, Beta (β⁻) decay, and Gamma (γ) emission alter the mass number (A) and atomic number (Z) of a parent nucleus?

Alpha decay (⁴₂He nucleus): A decreases by 4, Z decreases by 2. Beta-minus decay (⁰₋₁e electron from neutron -> proton + electron): A remains unchanged, Z increases by 1. Gamma emission (high-frequency electromagnetic photon): neither A nor Z changes.

In JAMB/WAEC Water Chemistry, what causes Temporary Hardness versus Permanent Hardness of water, and how is each removed?

Temporary hardness is caused by dissolved calcium or magnesium hydrogen trioxocarbonate(IV) [Ca(HCO3)2, Mg(HCO3)2] and is removed by boiling or adding slaked lime [Ca(OH)2]. Permanent hardness is caused by dissolved CaSO4, MgSO4, or chlorides and cannot be removed by boiling—it requires washing soda (Na2CO3), caustic soda (NaOH), permutit/ion-exchange resin, or distillation.

In JAMB/WAEC Chemical Bonding, why does water (H2O, molar mass 18) have a much higher boiling point (100°C) than hydrogen sulphide (H2S, molar mass 34, gas at room temperature)?

Because H2O molecules form strong intermolecular Hydrogen Bonds (due to the high electronegativity of oxygen), whereas H2S molecules only have weak van der Waals (dipole-dipole) forces.

In JAMB/WAEC Physics (Dimensions & Units), what are the fundamental SI units and dimensional formulas for Force, Work/Energy, Power, Pressure, and Momentum?

Force: Newton (N), [MLT⁻²]; Work/Energy: Joule (J), [ML²T⁻²]; Power: Watt (W), [ML²T⁻³]; Pressure/Stress/Young's Modulus: Pascal (Pa = N/m²), [ML⁻¹T⁻²]; Linear Momentum/Impulse: kg·m/s (N·s), [MLT⁻¹].

In JAMB/WAEC Kinematics & Projectile Motion, what are the formulas for Time of Flight (T), Maximum Height (H), and Horizontal Range (R) of a projectile launched at speed u and angle θ to the horizontal, and at what angle is Range maximum?

Time of flight T = (2u sin θ) / g; Maximum height H = (u² sin² θ) / (2g); Horizontal Range R = (u² sin 2θ) / g. Maximum horizontal range R_max = u²/g occurs when θ = 45° (since sin 90° = 1).

In JAMB/WAEC Electrostatics, how is the equivalent capacitance calculated for Capacitors in Parallel versus Capacitors in Series, and what is the energy stored in a capacitor?

Note that capacitors combine OPPOSITE to resistors: In Parallel: C_eq = C1 + C2 + C3; In Series: 1/C_eq = 1/C1 + 1/C2 + 1/C3. Energy stored W = ½ QV = ½ CV² = ½ Q²/C.

In JAMB/WAEC Organic Chemistry, what are the products of oxidation of a Primary (1°), Secondary (2°), and Tertiary (3°) alkanol with acidified K2Cr2O7 or KMnO4?

Primary alkanol (R-CH2OH) oxidizes first to an Alkanal (aldehyde) and on further oxidation to an Alkanoic acid (carboxylic acid). Secondary alkanol (R2CHOH) oxidizes to an Alkanone (ketone) only. Tertiary alkanol (R3COH) resists oxidation.

In JAMB/WAEC Chemistry, which separation technique is used to separate: (a) crude oil fractions, (b) ink dyes, (c) ammonium chloride from NaCl, and (d) immiscible liquids (kerosene and water)?

(a) Fractional distillation (based on close boiling points), (b) Chromatography (differential migration/adsorption), (c) Sublimation (NH4Cl, I2, camphor, and dry ice sublime directly from solid to gas), and (d) Separating funnel (immiscible liquids of different densities).

In JAMB/WAEC Industrial Chemistry, name the industrial process and catalyst used to manufacture: (a) H2SO4, (b) HNO3, (c) Sulphur extraction, and (d) Aluminium extraction.

(a) H2SO4: Contact Process using Vanadium(V) oxide (V2O5) catalyst; (b) HNO3: Ostwald Process using Platinum-Rhodium gauze catalyst; (c) Sulphur: Frasch Process (superheated water & hot compressed air through 3 concentric pipes); (d) Aluminium: Hall-Héroult electrolysis of purified Bauxite (Al2O3) dissolved in molten Cryolite (Na3AlF6).

In JAMB/WAEC Fluid Mechanics, state Archimedes' Principle and the Law of Flotation.

Archimedes' Principle: When a body is wholly or partially immersed in a fluid, it experiences an upward thrust (upthrust) equal to the weight of the fluid displaced. Law of Flotation: A floating body displaces its own weight of the fluid in which it floats.

In JAMB/WAEC Physics (Circular & Simple Harmonic Motion), what is the period (T) of a simple pendulum of length L, and how does the period change if its length is quadrupled (4L) or the bob's mass is doubled?

Period T = 2π√(L/g). Period is independent of the mass of the bob; if length L is quadrupled (4L), the period T doubles (√4 = 2).

In JAMB/WAEC Organic Chemistry, what is Esterification versus Saponification?

Esterification is the reversible reaction between an alkanol (alcohol) and an alkanoic (carboxylic) acid in the presence of concentrated H2SO4 catalyst to form a sweet-smelling ester and water. Saponification is the alkaline hydrolysis of fats/oils (triacylglycerols) by boiling with NaOH or KOH to produce soap (sodium/potassium salt of fatty acids) and propane-1,2,3-triol (glycerol).

In JAMB/WAEC Electrochemistry, state Faraday's First Law of Electrolysis and calculate the mass of copper (Cu = 64) deposited when a current of 2.0 A flows through CuSO4(aq) for 965 seconds (1 F = 96,500 C).

Faraday's First Law: Mass deposited (m) is directly proportional to quantity of electricity Q = It. For Cu²⁺ + 2e⁻ -> Cu, 2 Faradays (2 × 96,500 C) deposit 64 g of Cu. Here Q = 2.0 × 965 = 1,930 C. Mass m = (64 × 1,930) / (2 × 96,500) = 0.64 g.

In JAMB/WAEC Chemistry (Redox & Oxidation Numbers), what is the oxidation number of Chromium in K2Cr2O7 and Manganese in KMnO4?

In K2Cr2O7: 2(+1) + 2x + 7(-2) = 0 => 2x = 12 => x = +6 [Tetraoxochromate(VI) / Heptaoxodichromate(VI)]. In KMnO4: (+1) + x + 4(-2) = 0 => x = +7 [Tetraoxomanganate(VII)].

In JAMB/WAEC Current Electricity, how is a Galvanometer of resistance Rg and full-scale deflection current Ig converted into: (a) an Ammeter to read up to current I, and (b) a Voltmeter to read up to voltage V?

(a) To convert to an Ammeter, connect a low-resistance SHUNT resistor (R_s) in PARALLEL with the galvanometer: Ig·Rg = (I - Ig)·R_s. (b) To convert to a Voltmeter, connect a high-resistance MULTIPLIER resistor (R_m) in SERIES with the galvanometer: V = Ig(Rg + R_m).

JAMB & WAEC Chemistry & Physics: Stoichiometry, Gas Laws, Electrochemistry, Organic Chemistry, Mechanics, Waves, Electricity & Atomic Physics

Covers JAMB UTME & WAEC WASSCE Chemistry and Physics: Separation Techniques, Gas Laws, Periodic Table, Electrolysis (Faraday's Laws), Industrial Processes (Haber, Contact, Frasch), Organic Functional Groups, Kinematics, Projectile Motion, Simple Machines, Optics, Waves, Electricity, and Radioactivity.

Level: intermediate
Languages: en → en
Cards: 32
Markdown: JAMB & WAEC Chemistry & Physics: Stoichiometry, Gas Laws, Electrochemistry, Organic Chemistry, Mechanics, Waves, Electricity & Atomic Physics (.md)

Flashcards (32)

#	Front (Term / Question)	Back (Definition / Answer)
1	In JAMB/WAEC Acid-Base Titration, which indicator is suitable for: (a) Strong Acid + Strong Base, (b) Strong Acid + Weak Base, and (c) Weak Acid + Strong Base?	(a) Strong Acid + Strong Base (e.g., HCl + NaOH): Any indicator (Methyl orange or Phenolphthalein); (b) Strong Acid + Weak Base (e.g., HCl + NH3/Na2CO3): Methyl orange; (c) Weak Acid + Strong Base (e.g., CH3COOH or H2C2O4 + NaOH): Phenolphthalein.
2	In JAMB/WAEC Sound Waves (Pipes & Strings), what are the fundamental frequency (f0) and harmonics produced by a Closed Pipe of length L versus an Open Pipe or Stretched String of length L?	Closed pipe (node at closed end, antinode at open end, L = λ/4): f0 = v / (4L), producing ONLY odd harmonics (f0, 3f0, 5f0...). Open pipe or stretched string (L = λ/2): f0 = v / (2L), producing ALL harmonics—both odd and even (f0, 2f0, 3f0...).
3	In JAMB/WAEC Waves, what is the fundamental wave equation, and which wave properties distinguish Longitudinal waves from Transverse waves?	Wave speed v = fλ (where f is frequency in Hz and λ is wavelength in m). Only Transverse waves (light, electromagnetic waves, water/string waves) can be POLARIZED because their vibrations are perpendicular to the direction of wave propagation; Longitudinal waves (sound waves) vibrate parallel to propagation and cannot be polarized.
4	In JAMB/WAEC Thermal Physics, distinguish between Specific Heat Capacity (c) and Specific Latent Heat (L), and calculate the heat required to melt 0.5 kg of ice at 0°C (L_f = 3.36 × 10⁵ J/kg).	Specific heat capacity (Q = mcΔθ) is the heat required to raise the temperature of 1 kg of a substance by 1 K (with temperature change, no phase change). Specific latent heat (Q = mL) is the heat required to change the state of 1 kg of a substance at constant temperature. For 0.5 kg of ice: Q = mL_f = 0.5 × 3.36 × 10⁵ = 1.68 × 10⁵ J (168 kJ).
5	In JAMB/WAEC Electromagnetism, state the Transformer Voltage/Turns Ratio equation and list the 4 causes of energy loss in a practical transformer with their remedies.	Transformer equation: E_s / E_p = N_s / N_p = I_p / I_s (for 100% ideal transformer). Four energy losses & remedies: 1. Eddy currents -> Laminated soft-iron core; 2. Hysteresis loss -> Soft-iron core (easily magnetized/demagnetized); 3. Copper (I²R Joule heating) loss -> Thick low-resistance copper windings; 4. Flux leakage -> Winding secondary coils over primary on a closed core.
6	In JAMB/WAEC Stoichiometry, what volume does 1 mole of any ideal gas occupy at Standard Temperature and Pressure (STP: 0°C / 273 K and 1 atm / 760 mmHg), and what is Avogadro's constant?	Molar volume at STP = 22.4 dm³ (22,400 cm³); Avogadro's constant (NA) = 6.02 × 10²³ particles per mole.
7	In JAMB/WAEC Electrolysis, what factors determine the preferential discharge of ions at the electrodes during electrolysis of aqueous solutions?	1. Position of the ion in the Electrochemical Series (lower cations/anions are discharged first), 2. Concentration of the ions (high concentration of halide ion like Cl⁻ in brine overrides OH⁻), and 3. Nature of the electrode (e.g., mercury cathode discharges Na⁺ in the Castner-Kellner cell; reactive copper anode dissolves instead of discharging anions).
8	In JAMB/WAEC Optics, state the Mirror/Lens Equation and Snell's Law of Refraction, and state the two conditions required for Total Internal Reflection (TIR).	Mirror/Lens equation: 1/f = 1/u + 1/v (Magnification M = v/u = h_i/h_o). Snell's Law: n = sin i / sin r = real depth / apparent depth = 1 / sin C (where C is the critical angle). Conditions for TIR: 1. Light must travel from an optically denser medium to an optically less dense medium, and 2. The angle of incidence in the denser medium must exceed the critical angle (i > C).
9	In JAMB/WAEC Radioactivity, if a radioactive isotope has a half-life (T_1/2) of 5 days, what fraction and mass of an initial 80 g sample remain undecayed after 20 days?	Number of half-lives n = 20 / 5 = 4 half-lives. Remaining fraction = (1/2)^n = (1/2)⁴ = 1/16. Remaining undecayed mass = 80 g / 16 = 5 g (meaning 75 g has decayed).
10	In JAMB/WAEC Atomic & Quantum Physics, state Einstein's Photoelectric Equation and define Work Function (W0) and Threshold Frequency (f0).	Einstein's Photoelectric Equation: E = hf = W0 + K_max (where hf = hf0 + ½mv_max²). Work function W0 = hf0 is the minimum energy required to liberate a photoelectron from a metal surface; Threshold frequency f0 is the minimum frequency of incident radiation below which no photoelectric emission occurs regardless of intensity.
11	In JAMB/WAEC Chemical Equilibrium (Le Chatelier's Principle), in the exothermic Haber Process N2(g) + 3H2(g) ⇌ 2NH3(g) (ΔH = -92 kJ/mol), what conditions maximize the yield of ammonia, and what catalyst is used?	High pressure (200–250 atm, since forward reaction reduces moles from 4 to 2), moderate temperature (~450°C—low enough to favor exothermic forward yield, high enough for reaction rate), finely divided Iron (Fe) catalyst with Al2O3 promoter, and continuous removal of NH3.
12	In JAMB/WAEC Mechanics (Elasticity), state Hooke's Law and give the formula for elastic potential energy stored in a stretched spring or wire.	Hooke's Law states that provided the elastic limit is not exceeded, the extension (e) of an elastic material is directly proportional to the applied force/load (F = ke). Elastic potential energy stored E = ½ Fe = ½ ke².
13	In JAMB/WAEC Mechanics (Simple Machines), how are Mechanical Advantage (MA), Velocity Ratio (VR), and Efficiency (η) related, and what is the VR of an inclined plane of angle θ and a block-and-tackle pulley system with n pulleys?	Efficiency η = (MA / VR) × 100%, where MA = Load / Effort and VR = Distance moved by Effort / Distance moved by Load. For an inclined plane, VR = 1 / sin θ; for a block-and-tackle pulley system with n pulleys, VR = n.
14	In JAMB/WAEC Organic Chemistry, what reagents distinguish saturated Alkanes from unsaturated Alkenes and terminal Alkynes?	Unsaturated alkenes and alkynes decolourize reddish-brown Bromine water (Br2/CCl4) and purple acidified KMnO4 (Baeyer's reagent), whereas alkanes do not. Terminal alkynes (containing -C≡C-H) additionally react with ammoniacal Copper(I) chloride to give a reddish-brown precipitate and with ammoniacal Silver trioxonitrate(V) (Tollens' reagent) to give a white/yellow-white precipitate; alkenes do not.
15	In JAMB/WAEC Gas Laws, state Graham's Law of Diffusion and calculate the relative rate of diffusion of Hydrogen gas (M = 2) compared to Oxygen gas (M = 32).	Graham's Law states that at constant temperature and pressure, the rate of diffusion of a gas is inversely proportional to the square root of its vapour density or molar mass: R1/R2 = √(M2/M1). For H2 and O2: R(H2)/R(O2) = √(32/2) = √16 = 4 (Hydrogen diffuses 4 times faster than Oxygen).
16	In JAMB/WAEC Qualitative Analysis, how do you test for and distinguish between Iron(II) (Fe²⁺), Iron(III) (Fe³⁺), Copper(II) (Cu²⁺), and Zinc (Zn²⁺) ions using NaOH(aq) and NH3(aq)?	Fe²⁺: dirty-green gelatinous precipitate insoluble in excess NaOH and NH3; Fe³⁺: reddish-brown precipitate insoluble in excess NaOH and NH3; Cu²⁺: pale blue precipitate insoluble in excess NaOH, but dissolves in excess NH3 to form a deep blue solution; Zn²⁺: white gelatinous precipitate soluble in BOTH excess NaOH and excess NH3.
17	In JAMB/WAEC Alternating Current (AC) Circuits, what is the Impedance (Z) of a series R-L-C circuit, and what is the condition for Resonance?	Impedance Z = √[R² + (X_L - X_C)²], where Inductive reactance X_L = 2πfL and Capacitive reactance X_C = 1 / (2πfC). Resonance occurs when X_L = X_C, making impedance minimum (Z = R), current maximum, and resonant frequency f0 = 1 / [2π√(LC)].
18	In JAMB/WAEC Radioactivity, how do Alpha (α) decay, Beta (β⁻) decay, and Gamma (γ) emission alter the mass number (A) and atomic number (Z) of a parent nucleus?	Alpha decay (⁴₂He nucleus): A decreases by 4, Z decreases by 2. Beta-minus decay (⁰₋₁e electron from neutron -> proton + electron): A remains unchanged, Z increases by 1. Gamma emission (high-frequency electromagnetic photon): neither A nor Z changes.
19	In JAMB/WAEC Water Chemistry, what causes Temporary Hardness versus Permanent Hardness of water, and how is each removed?	Temporary hardness is caused by dissolved calcium or magnesium hydrogen trioxocarbonate(IV) [Ca(HCO3)2, Mg(HCO3)2] and is removed by boiling or adding slaked lime [Ca(OH)2]. Permanent hardness is caused by dissolved CaSO4, MgSO4, or chlorides and cannot be removed by boiling—it requires washing soda (Na2CO3), caustic soda (NaOH), permutit/ion-exchange resin, or distillation.
20	In JAMB/WAEC Chemical Bonding, why does water (H2O, molar mass 18) have a much higher boiling point (100°C) than hydrogen sulphide (H2S, molar mass 34, gas at room temperature)?	Because H2O molecules form strong intermolecular Hydrogen Bonds (due to the high electronegativity of oxygen), whereas H2S molecules only have weak van der Waals (dipole-dipole) forces.
21	In JAMB/WAEC Physics (Dimensions & Units), what are the fundamental SI units and dimensional formulas for Force, Work/Energy, Power, Pressure, and Momentum?	Force: Newton (N), [MLT⁻²]; Work/Energy: Joule (J), [ML²T⁻²]; Power: Watt (W), [ML²T⁻³]; Pressure/Stress/Young's Modulus: Pascal (Pa = N/m²), [ML⁻¹T⁻²]; Linear Momentum/Impulse: kg·m/s (N·s), [MLT⁻¹].
22	In JAMB/WAEC Kinematics & Projectile Motion, what are the formulas for Time of Flight (T), Maximum Height (H), and Horizontal Range (R) of a projectile launched at speed u and angle θ to the horizontal, and at what angle is Range maximum?	Time of flight T = (2u sin θ) / g; Maximum height H = (u² sin² θ) / (2g); Horizontal Range R = (u² sin 2θ) / g. Maximum horizontal range R_max = u²/g occurs when θ = 45° (since sin 90° = 1).
23	In JAMB/WAEC Electrostatics, how is the equivalent capacitance calculated for Capacitors in Parallel versus Capacitors in Series, and what is the energy stored in a capacitor?	Note that capacitors combine OPPOSITE to resistors: In Parallel: C_eq = C1 + C2 + C3; In Series: 1/C_eq = 1/C1 + 1/C2 + 1/C3. Energy stored W = ½ QV = ½ CV² = ½ Q²/C.
24	In JAMB/WAEC Organic Chemistry, what are the products of oxidation of a Primary (1°), Secondary (2°), and Tertiary (3°) alkanol with acidified K2Cr2O7 or KMnO4?	Primary alkanol (R-CH2OH) oxidizes first to an Alkanal (aldehyde) and on further oxidation to an Alkanoic acid (carboxylic acid). Secondary alkanol (R2CHOH) oxidizes to an Alkanone (ketone) only. Tertiary alkanol (R3COH) resists oxidation.
25	In JAMB/WAEC Chemistry, which separation technique is used to separate: (a) crude oil fractions, (b) ink dyes, (c) ammonium chloride from NaCl, and (d) immiscible liquids (kerosene and water)?	(a) Fractional distillation (based on close boiling points), (b) Chromatography (differential migration/adsorption), (c) Sublimation (NH4Cl, I2, camphor, and dry ice sublime directly from solid to gas), and (d) Separating funnel (immiscible liquids of different densities).
26	In JAMB/WAEC Industrial Chemistry, name the industrial process and catalyst used to manufacture: (a) H2SO4, (b) HNO3, (c) Sulphur extraction, and (d) Aluminium extraction.	(a) H2SO4: Contact Process using Vanadium(V) oxide (V2O5) catalyst; (b) HNO3: Ostwald Process using Platinum-Rhodium gauze catalyst; (c) Sulphur: Frasch Process (superheated water & hot compressed air through 3 concentric pipes); (d) Aluminium: Hall-Héroult electrolysis of purified Bauxite (Al2O3) dissolved in molten Cryolite (Na3AlF6).
27	In JAMB/WAEC Fluid Mechanics, state Archimedes' Principle and the Law of Flotation.	Archimedes' Principle: When a body is wholly or partially immersed in a fluid, it experiences an upward thrust (upthrust) equal to the weight of the fluid displaced. Law of Flotation: A floating body displaces its own weight of the fluid in which it floats.
28	In JAMB/WAEC Physics (Circular & Simple Harmonic Motion), what is the period (T) of a simple pendulum of length L, and how does the period change if its length is quadrupled (4L) or the bob's mass is doubled?	Period T = 2π√(L/g). Period is independent of the mass of the bob; if length L is quadrupled (4L), the period T doubles (√4 = 2).
29	In JAMB/WAEC Organic Chemistry, what is Esterification versus Saponification?	Esterification is the reversible reaction between an alkanol (alcohol) and an alkanoic (carboxylic) acid in the presence of concentrated H2SO4 catalyst to form a sweet-smelling ester and water. Saponification is the alkaline hydrolysis of fats/oils (triacylglycerols) by boiling with NaOH or KOH to produce soap (sodium/potassium salt of fatty acids) and propane-1,2,3-triol (glycerol).
30	In JAMB/WAEC Electrochemistry, state Faraday's First Law of Electrolysis and calculate the mass of copper (Cu = 64) deposited when a current of 2.0 A flows through CuSO4(aq) for 965 seconds (1 F = 96,500 C).	Faraday's First Law: Mass deposited (m) is directly proportional to quantity of electricity Q = It. For Cu²⁺ + 2e⁻ -> Cu, 2 Faradays (2 × 96,500 C) deposit 64 g of Cu. Here Q = 2.0 × 965 = 1,930 C. Mass m = (64 × 1,930) / (2 × 96,500) = 0.64 g.
31	In JAMB/WAEC Chemistry (Redox & Oxidation Numbers), what is the oxidation number of Chromium in K2Cr2O7 and Manganese in KMnO4?	In K2Cr2O7: 2(+1) + 2x + 7(-2) = 0 => 2x = 12 => x = +6 [Tetraoxochromate(VI) / Heptaoxodichromate(VI)]. In KMnO4: (+1) + x + 4(-2) = 0 => x = +7 [Tetraoxomanganate(VII)].
32	In JAMB/WAEC Current Electricity, how is a Galvanometer of resistance Rg and full-scale deflection current Ig converted into: (a) an Ammeter to read up to current I, and (b) a Voltmeter to read up to voltage V?	(a) To convert to an Ammeter, connect a low-resistance SHUNT resistor (R_s) in PARALLEL with the galvanometer: Ig·Rg = (I - Ig)·R_s. (b) To convert to a Voltmeter, connect a high-resistance MULTIPLIER resistor (R_m) in SERIES with the galvanometer: V = Ig(Rg + R_m).