CG PET flashcards
CG PET · Build recall with a focused review session.
31 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Newton's second law
- The net force on a body equals its mass times acceleration, ΣF = ma. Acceleration points in the direction of the net force and is zero when forces balance.
- Kinetic energy
- Energy of motion given by KE = ½mv², where m is mass in kilograms and v is speed in metres per second. It is a scalar and scales with the square of speed.
- Conservation of momentum
- In a system with no net external force, total momentum p = mv stays constant. This holds in all collisions, elastic or inelastic, and underlies rocket propulsion.
- Centripetal acceleration
- For uniform circular motion, acceleration a = v²/r directed toward the centre of the circle. The speed is constant but the direction of velocity changes continuously.
- Ohm's law
- For a conductor at constant temperature, current is proportional to potential difference: V = IR. Resistance R is in ohms when V is volts and I is amperes.
- Wave equation
- Wave speed equals frequency multiplied by wavelength, v = fλ. When a wave enters a new medium, frequency is unchanged while speed and wavelength change.
- Snell's law
- Refraction at a boundary obeys n₁ sin θ₁ = n₂ sin θ₂, with angles measured from the normal. Light bends toward the normal when entering a denser medium.
- Specific heat capacity
- Heat needed to raise unit mass by one kelvin, used as Q = mcΔT. Water's high value, about 4200 J/(kg·K), explains its slow heating and cooling.
- Resistors in parallel
- Parallel resistors share the same voltage and combine as 1/R = 1/R₁ + 1/R₂ + …, so total resistance is less than the smallest individual resistance.
- The mole
- Amount of substance containing 6.022 × 10²³ particles, Avogadro's number. Moles are found from mass divided by molar mass, or from gas volume at STP.
- Molarity
- Concentration expressed as moles of solute per litre of solution, unit mol/L. Dilution keeps moles constant, so M₁V₁ = M₂V₂ applies.
- Limiting reagent
- The reactant consumed first, which caps product yield. Find it by dividing each reactant's moles by its coefficient and choosing the smallest ratio.
- pH scale
- pH = −log[H⁺], so a tenfold change in hydrogen ion concentration shifts pH by one unit. Values below 7 are acidic, above 7 basic at 25 °C.
- Ideal gas law
- PV = nRT relates pressure, volume, moles and absolute temperature, with R = 8.314 J/(mol·K). Temperature must be in kelvin or the calculation fails.
- Oxidation and reduction
- Oxidation is loss of electrons and an increase in oxidation number; reduction is gain. The oxidising agent accepts electrons and is itself reduced.
- Ionic bonding
- Electrostatic attraction between oppositely charged ions formed by electron transfer, typically metal to non-metal. These compounds conduct when molten or dissolved, not as solids.
- Periodic trend across a period
- Moving left to right, nuclear charge rises while shells stay the same, so atomic radius falls and ionisation energy and electronegativity increase.
- Empirical formula
- Simplest whole-number ratio of atoms in a compound. Obtain it by converting percentage masses to moles and dividing by the smallest value.
- Catalyst
- A substance that speeds a reaction by providing an alternative pathway with lower activation energy, without being consumed. It does not change the equilibrium position.
- Electronegativity
- Tendency of an atom to attract shared electrons in a bond. Large differences between bonded atoms give ionic character; small differences give nonpolar covalent bonds.
- Quadratic formula
- For ax² + bx + c = 0 with a ≠ 0, x = [−b ± √(b² − 4ac)]/2a. The discriminant b² − 4ac determines whether real roots exist.
- Discriminant
- The quantity b² − 4ac in a quadratic. Positive means two distinct real roots, zero means one repeated root, negative means no real roots.
- Power rule
- For differentiation, d/dx xⁿ = nxⁿ⁻¹. For integration, ∫xⁿ dx = xⁿ⁺¹/(n+1) + C, valid for every n except n = −1.
- Product rule
- The derivative of a product uv is u′v + uv′, where primes denote derivatives. The quotient rule is (u′v − uv′)/v² for v ≠ 0.
- Chain rule
- For a composite function, differentiate the outer function and multiply by the derivative of the inner function: d/dx f(g(x)) = f′(g(x))·g′(x).
- Logarithm laws
- log(xy) = log x + log y, log(x/y) = log x − log y, and log xⁿ = n log x. Change of base uses log_b x = ln x / ln b.
- Sine rule
- In any triangle, a/sin A = b/sin B = c/sin C, where each side is opposite its named angle. It is used when two angles and one side are known.
- Cosine rule
- a² = b² + c² − 2bc cos A generalises Pythagoras to any triangle. It finds a side from two sides and the included angle, or an angle from three sides.
- Geometric progression sum
- For first term a and ratio r ≠ 1, the sum of n terms is a(1 − rⁿ)/(1 − r). An infinite sum converges only when |r| < 1, to a/(1 − r).
- Perpendicular line slopes
- Two non-vertical lines are perpendicular exactly when their slopes multiply to −1, so the perpendicular slope is the negative reciprocal of the original.
- Definite integral as area
- The definite integral of a function from a to b gives the signed area between the curve and the x-axis, counting regions below the axis as negative.