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medium importance~1 Q in Tier 113 formulas⚡ 11 shortcuts5 subtopics

Every formula in this topic, grouped by subtopic. Print it and pin it above your desk.

Matter, separation methods and atomic structure

Moles from mass
n = \frac{m}{M}

M = molar mass in g/mol

Number of particles
N = n \times N_A,\quad N_A = 6.022 \times 10^{23}

Avogadro number

Boyle's law
P_1V_1 = P_2V_2

temperature constant

Charles's law
\frac{V_1}{T_1} = \frac{V_2}{T_2}

pressure constant, T in kelvin

Ideal gas equation
PV = nRT

R = 8.314 J mol⁻¹ K⁻¹

Maximum electrons in a shell
2n^{2}

K = 2, L = 8, M = 18

Acids, bases, pH, common compounds and reactions

pH
\text{pH} = -\log_{10}[\text{H}^{+}]

pH + pOH = 14 at 25 °C

Neutralisation
\text{Acid} + \text{Base} \rightarrow \text{Salt} + \text{H}_2\text{O}
Setting of Plaster of Paris
\text{CaSO}_4\cdot\tfrac{1}{2}\text{H}_2\text{O} + 1\tfrac{1}{2}\,\text{H}_2\text{O} \rightarrow \text{CaSO}_4\cdot 2\text{H}_2\text{O}

PoP → gypsum

Metals, ores, metallurgy and alloys

Gold purity
\text{Purity}\,(\%) = \frac{\text{carat}}{24} \times 100

22 ct ≈ 91.67%

Carbon compounds, fuels, polymers, industry and pollution

Alkane / alkene / alkyne
C_nH_{2n+2},\quad C_nH_{2n},\quad C_nH_{2n-2}
Haber process
N_2 + 3H_2 \rightleftharpoons 2NH_3

iron catalyst

Complete combustion of methane
CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O