All flashcard decks HKDSE (Hong Kong) syllabus →

30 cardsHKDSE (Hong Kong)

HKDSE Physics and Chemistry Formulae

Flashcards on the key equations in HKDSE Physics and Chemistry: motion, energy, heat, electricity, waves, moles, concentration and pH. Original study material.

Start studying Play Match

PDF study sheet

Free account needed to save, copy or download. We bring you back here.

1 / 30

0 known

TermClick or press Space to flip

Equation: speed from acceleration (uniform motion)

GetMyMockTestQuestion side

Full list

Terms in this deck (30)

HKDSE (Hong Kong) mock tests →

Equation: speed from acceleration (uniform motion)

v = u + a t

Distance with uniform acceleration

s = u t + \frac{1}{2} a t^{2}

Newton's second law

F = ma

: net force equals mass times acceleration.

Kinetic energy

E_{k} = \frac{1}{2} m v^{2}

Gravitational potential energy near the Earth

E_{p} = m g h

Power

P = \frac{W}{t}

(also

P = F v

Efficiency

\frac{useful output}{total input} \times 100%

Heat needed to change temperature

Q = m c Δ T

Heat needed to change state

Q = m l

, with

l

the specific latent heat.

Boyle's law

At constant temperature

p_{1} V_{1} = p_{2} V_{2}

Pressure law

At constant volume

\frac{p _{1}}{T _{1}} = \frac{p _{2}}{T _{2}}

, with

T

in kelvin.

Wave equation

v = f λ

Relationship between frequency and period

f = \frac{1}{T}

Lens formula

\frac{1}{u} + \frac{1}{v} = \frac{1}{f}

(real-is-positive convention).

Ohm's law

V = I R

Resistors in series and in parallel

Series:

R = R_{1} + R_{2}

. Parallel:

\frac{1}{R} = \frac{1}{R _{1}} + \frac{1}{R _{2}}

Electrical power

P = V I = I^{2} R = \frac{V ^{2}}{R}

Ideal transformer

\frac{V _{s}}{V _{p}} = \frac{N _{s}}{N _{p}}

Charge passing a point

Q = I t

Half-life rule

After

n

half-lives, the amount left is

(\frac{1}{2})^{n}

of the original.

Moles from mass

n = \frac{m}{M _{r}}

Concentration in mol/dm

^{3}

c = \frac{n}{V}

, with

V

in dm

^{3}

Molar volume of a gas at r.t.p. used in HKDSE

24 dm

^{3}

per mole.

Dilution

c_{1} V_{1} = c_{2} V_{2}

Percentage by mass of an element in a compound

\frac{atoms \times A _{r}}{M _{r}} \times 100%

pH of a solution

pH = - lo g_{10} [H^{+}]

Relationship between pH and pOH at 25 °C

pH + pOH = 14

Oxidation is

Loss of electrons (OIL RIG): the oxidation number increases.

Reduction is

Gain of electrons: the oxidation number decreases.

General formula of the alkanes, alkenes and alkynes

Alkanes C

_{n}

_{2 n + 2}

; alkenes C

_{n}

_{2 n}

; alkynes C

_{n}

_{2 n - 2}

More HKDSE (Hong Kong) practice

HKDSE (Hong Kong) mock tests

All HKDSE (Hong Kong) practice →