Memory hooks and mnemonics.

“Please Send Cats, Monkeys And Zebras In Large Cages Securely Guarded”

Reactivity series of metals

Potassium, Sodium, Calcium, Magnesium, Aluminium, Zinc, Iron, Lead, Copper, Silver, Gold. A metal higher in the list displaces one lower down from its salt solution.

“OIL RIG”

Oxidation and reduction

Oxidation Is Loss of electrons, Reduction Is Gain of electrons. The oxidising agent is itself reduced.

“LEO says GER”

The same idea, said the other way

Lose Electrons Oxidation, Gain Electrons Reduction. Use whichever sticks.

“HOFBrINCl”

The diatomic elements

Hydrogen, Oxygen, Fluorine, Bromine, Iodine, Nitrogen, Chlorine. These exist as X₂ molecules, not single atoms.

“Red Cat, An Ox”

Electrode reactions

REDuction at the CAThode, ANode is OXidation. True in both galvanic and electrolytic cells.

“ILATE”

Choosing u in integration by parts

Inverse, Logarithmic, Algebraic, Trigonometric, Exponential. Whichever comes first in the list becomes u.

“Monkeys Eat Peeled Bananas”

First four alkanes

Methane, Ethane, Propane, Butane: 1, 2, 3 and 4 carbon atoms, in that order.

“Left hand for motors, right hand for generators”

Fleming's rules

Left-hand rule gives the direction of force on a current-carrying conductor (a motor). Right-hand rule gives induced current (a generator).

“First, seCond, thuMb”

Fleming's finger assignment

First finger = Field, seCond finger = Current, thuMb = Motion. Hold them mutually perpendicular.

“ROY G BIV”

The visible spectrum in order

Red, Orange, Yellow, Green, Blue, Indigo, Violet. Red has the longest wavelength and bends least.

“Real is inverted, virtual is erect”

Image nature in mirrors and lenses

A real image can be caught on a screen and is inverted. A virtual image cannot and is erect.

“Convex collects, concave scatters”

Lens behaviour

A convex (converging) lens has positive power; a concave (diverging) lens has negative power.

“CIVIL”

Phase in AC circuits

In a Capacitor, I leads V (C-I-V); in an inductor, V leads I (V-I-L). Read the word from both ends.

“King Philip Came Over For Good Soup”

Taxonomic hierarchy

Kingdom, Phylum, Class, Order, Family, Genus, Species, in descending order of breadth.

“Please Pass Some Tea”

Order of a food chain

Producer, Primary consumer, Secondary consumer, Tertiary consumer. Only about 10% of the energy passes on to each next level.

“A vein carries blood TO the heart, an artery carries it AWAY”

Blood vessels

The exceptions are the pulmonary vein (oxygenated, to the heart) and the pulmonary artery (deoxygenated, away).

“Mitochondria: the powerhouse; Ribosome: the factory; Lysosome: the suicide bag”

Organelle functions

Three one-line handles that answer most short-answer organelle questions.

“All Students Take Calculus”

Sign of trigonometric ratios by quadrant

Quadrant I: All positive. II: Sine positive. III: Tangent positive. IV: Cosine positive.

“SOH CAH TOA”

The basic ratios

Sin = Opposite/Hypotenuse, Cos = Adjacent/Hypotenuse, Tan = Opposite/Adjacent.

“0, ½, 1/√2, √3⁄2, 1”

sin values at 0°, 30°, 45°, 60°, 90°

Write √0/2, √1/2, √2/2, √3/2, √4/2 and simplify. Cos is the same row backwards.

“BODMAS”

Order of operations

Brackets, Orders (powers and roots), Division and Multiplication, Addition and Subtraction.