GCSE Chemistry & Physics Revision

Cards · 50

Weight Formula

W = m * g. W = weight (N), m = mass (kg), g = gravitational field strength (N/kg, ~9.8 on Earth). Use to find the force of gravity acting on an object.

Work Done Formula

W = F * s. W = work done (J), F = force (N), s = distance moved along force line (m). Use when calculating energy transferred by an applied force.

Hooke's Law Formula

F = k * e. F = force (N), k = spring constant (N/m), e = extension (m). Applies to elastic materials within their limit of proportionality.

Moment of a Force Formula

M = F * d. M = moment (N m), F = force (N), d = perpendicular distance to pivot (m). Use to determine turning effects around a fixed axis.

Pressure on a Surface Formula

p = F / A. p = pressure (Pa), F = normal force (N), A = area (m^2). Use to find stress or contact force distributed over a surface.

Fluid Pressure at Depth Formula

p = h * rho * g. p = pressure (Pa), h = depth (m), rho = density (kg/m^3), g = gravity (N/kg). Calculates pressure exerted by a fluid column.

Average Speed Formula

s = d / t. s = speed (m/s), d = distance (m), t = time (s). Applies to constant speed or calculating mean speed over a journey.

Acceleration Formula

a = (v - u) / t. a = acceleration (m/s^2), v = final velocity (m/s), u = initial velocity (m/s), t = time (s). Measures rate of velocity change.

Uniform Acceleration Equation

v^2 - u^2 = 2 * a * s. v = final velocity, u = initial velocity, a = acceleration, s = displacement. Use when time is unknown under constant acceleration.

Newton's Second Law Formula

F = m * a. F = resultant force (N), m = mass (kg), a = acceleration (m/s^2). Use to calculate net force needed to accelerate a given mass.

Linear Momentum Formula

p = m * v. p = momentum (kg m/s), m = mass (kg), v = velocity (m/s). Applied in conservation of momentum problems during collisions.

Kinetic Energy Formula

Ek = 0.5 * m * v^2. Ek = kinetic energy (J), m = mass (kg), v = speed (m/s). Calculates energy stored in a moving body.

Gravitational Potential Energy Formula

Ep = m * g * h. Ep = potential energy (J), m = mass (kg), g = gravity (N/kg), h = height (m). Use for energy changes during vertical motion.

Power (Work Done) Formula

P = W / t. P = power (W), W = work done or energy (J), t = time (s). Calculates the rate at which energy is transferred or work is done.

Efficiency Formula

Efficiency = (Useful output energy / Total input energy) * 100%. Dimensionless ratio or %. Measures proportion of energy not wasted.

Wave Speed Equation

v = f * lambda. v = wave speed (m/s), f = frequency (Hz), lambda = wavelength (m). Applies to both transverse and longitudinal wave motion.

Wave Period Equation

T = 1 / f. T = period (s), f = frequency (Hz). Use to find the time taken for one complete wave oscillation.

Current and Charge Formula

Q = I * t. Q = charge (C), I = current (A), t = time (s). Calculates total electric charge passing a point over an interval.

Ohm's Law Formula

V = I * R. V = potential difference (V), I = current (A), R = resistance (ohms). Applies across ohmic conductors at constant temperature.

Resistors in Series Formula

R_total = R1 + R2 + ... R = resistance (ohms). Sum the individual resistances to get the equivalent resistance in a single loop.

Electrical Power (Current & Voltage)

P = I * V. P = power (W), I = current (A), V = potential difference (V). Calculates electrical energy dissipated per second in a component.

Electrical Power (Current & Resistance)

P = I^2 * R. P = power (W), I = current (A), R = resistance (ohms). Used to find heating losses in wires and circuit components.

Electrical Energy Transferred (Charge)

E = Q * V. E = energy (J), Q = charge (C), V = potential difference (V). Calculates work done when a charge moves through a voltage drop.

Density Formula

rho = m / V. rho = density (kg/m^3), m = mass (kg), V = volume (m^3). Use to determine mass concentration of solids, liquids, or gases.

Specific Heat Capacity Formula

Delta E = m * c * Delta theta. Delta E = energy (J), m = mass (kg), c = specific heat capacity (J/kg deg C), Delta theta = temp change (deg C).

Specific Latent Heat Formula

E = m * L. E = energy (J), m = mass (kg), L = latent heat (J/kg). Use during phase changes (fusion or vaporisation) at constant temp.

Boyle's Law (Gas Pressure & Volume)

p * V = constant. p = pressure (Pa), V = volume (m^3). Applies to a fixed mass of gas at constant temperature.

Transformer Equation (Voltage)

Vp / Vs = Np / Ns. V = voltage (V), N = turn count, p = primary, s = secondary. Use to calculate step-up or step-down voltage ratios.

Ideal Transformer Equation (Power)

Vs * Is = Vp * Ip. V = voltage (V), I = current (A), p = primary, s = secondary. Assumes 100% efficiency in electrical power transmission.

Magnetic Force on a Wire

F = B * I * l. F = force (N), B = magnetic flux density (T), I = current (A), l = wire length (m). Applies when wire is perpendicular to field.

Refractive Index (Snell's Law)

n = sin(i) / sin(r). n = refractive index, i = angle of incidence, r = angle of refraction. Use for light passing between medium boundaries.

Magnification Formula

Magnification = image height / object height. Dimensionless ratio. Use for lenses, curved mirrors, or microscope scale calculations.

Moles from Mass Formula

n = m / Mr. n = amount of substance (mol), m = mass (g), Mr = relative formula mass (g/mol). Primary formula for stoichiometry.

Moles in Solution Formula

n = c * V. n = moles (mol), c = concentration (mol/dm^3), V = volume (dm^3). Used for solution preparation and titration calculations.

Mass Concentration Formula

c = m / V. c = concentration (g/dm^3), m = mass of solute (g), V = volume of solution (dm^3). Use to convert solution mass into concentration.

Molar Gas Volume Formula

V = n * 24. V = gas volume (dm^3), n = moles (mol). Constant 24 dm^3/mol holds at room temperature and pressure (r.t.p.).

Percentage Yield Formula

Percentage Yield = (actual yield / theoretical yield) * 100%. Both yields in g or mol. Quantifies product loss in a chemical reaction.

Atom Economy Formula

Atom Economy = (Mr of desired product / total Mr of all reactants) * 100%. Measures sustainability and efficiency of reaction pathways.

Rate of Reaction Formula

Rate = amount of reactant used or product formed / time. Units: g/s, cm^3/s, or mol/s. Found via tangents on reaction graphs.

Chromatography Rf Value Formula

Rf = distance moved by substance / distance moved by solvent. Dimensionless value between 0 and 1. Used to identify separated compounds.

Bond Energy (Enthalpy Change)

Delta H = Energy required to break bonds - Energy released forming bonds. Delta H in kJ/mol. Negative = exothermic, positive = endothermic.

Relative Atomic Mass (Ar) Formula

Ar = sum of (isotope mass * % abundance) / 100. Accounts for natural isotopic distribution to find average atomic mass.

Number of Particles (Avogadro)

N = n * NA. N = number of particles, n = moles (mol), NA = Avogadro constant (6.02 * 10^23 mol^-1). Converts moles to individual atoms.

Stopping Distance Concept

Stopping Distance = Thinking Distance + Braking Distance. Thinking depends on speed and reaction; braking depends on speed squared and friction.

Half-life Concept

Time taken for radioactive nuclei or activity to halve. Activity = Initial Activity / (2^n), where n = number of half-lives elapsed.

Alpha Decay Equation Form

A_Z X -> A-4_Z-2 Y + 4_2 He. Mass number decreases by 4, atomic number decreases by 2 due to emission of a helium nucleus.

Beta Minus Decay Equation Form

A_Z X -> A_Z+1 Y + 0_-1 e. A neutron turns into a proton; mass number is unchanged, atomic number increases by 1 with electron emission.

Electrolysis Cathode Rule (Aqueous)

Hydrogen gas forms if the metal is more reactive than hydrogen; otherwise, the metal deposits. Driven by reduction (electron gain).

Electrolysis Anode Rule (Aqueous)

Halide ions form halogen gas; if no halide is present, oxygen gas is produced from OH- ions. Driven by oxidation (electron loss).

Gas Chromatography Retention Time

Time taken for a compound to travel through the chromatographic column. Used to identify volatile substances by comparing to standards.