CHEMISTRY FLASHCARDS (CIE 0620)

States of matter (solids)

Particles closely packed, regular arrangement, vibrate in fixed positions, strong forces of attraction

States of matter (liquids)

Particles close together but irregular, move past each other, weaker forces than solids

States of matter (gases)

Particles far apart, random motion, negligible forces, compressible

Diffusion

Net movement of particles from high to low concentration due to random motion

Atom structure

Central nucleus (protons + neutrons) with electrons in shells

Proton

Relative charge +1, mass 1

Electron

Relative charge -1, mass 1/1836

Neutron

No charge, mass 1

Isotopes

Same number of protons, different number of neutrons

Ionic bonding

Electrostatic attraction between oppositely charged ions

Properties of ionic compounds

High melting point, conduct electricity when molten/aqueous, not solid

Covalent bonding

Sharing of electron pairs between atoms

Simple molecular substances

Low melting/boiling points, weak intermolecular forces, poor conductors

Giant covalent structures

Strong covalent bonds throughout structure, high melting point

Metallic bonding

Positive ions in lattice with delocalised electrons

Properties of metals

Conduct electricity, malleable, ductile

Mole

Amount of substance containing 6.02 × 10^23 particles

Mole formula

Amount = mass ÷ molar mass

Relative atomic mass

Weighted average mass of isotopes compared to carbon-12

Electrolysis

Decomposition of ionic compound using electricity

Anode

Positive electrode, oxidation occurs

Cathode

Negative electrode, reduction occurs

Oxidation

Loss of electrons / gain of oxygen

Reduction

Gain of electrons / loss of oxygen

Exothermic reaction

Releases energy, temperature increases

Endothermic reaction

Absorbs energy, temperature decreases

Activation energy

Minimum energy required for reaction

Rate of reaction

Change in amount of reactant/product per unit time

Factors affecting rate

Temperature, concentration, surface area, catalyst

Catalyst

Increases rate without being used up, lowers activation energy

Reversible reaction

Reaction that can go forward and backward

Equilibrium

Forward and reverse reactions occur at same rate

Acid

Proton donor, produces H+ in solution

Base

Proton acceptor

Alkali

Soluble base producing OH-

pH scale

Measures acidity/alkalinity (0–14)

Neutralisation

Acid + base → salt + water

Periodic table

Elements arranged by increasing atomic number

Group

Vertical column, same number of outer electrons

Period

Horizontal row, same number of shells

Metals

Good conductors, lose electrons to form cations

Non-metals

Poor conductors, gain electrons to form anions

Reactivity series

Order of metals based on reactivity

Rusting

Iron reacts with oxygen and water to form hydrated iron(III) oxide

Alloy

Mixture of metal with other elements to improve properties

Crude oil

Mixture of hydrocarbons

Alkanes

Saturated hydrocarbons, single bonds

Alkenes

Unsaturated hydrocarbons, contain C=C double bond

Cracking

Breaking long hydrocarbons into smaller ones

Combustion

Reaction with oxygen releasing energy

Test for hydrogen

Squeaky pop with lit splint

Test for oxygen

Relights glowing splint

Test for carbon dioxide

Turns limewater milky

Chromatography

Separates substances based on solubility and attraction