National 5 Chemistry Flashcards

Flashcards for National 5 Chemistry Unit 1 Summary Notes

Element

A substance made up of only one type of atom that cannot be broken down into simpler substances.

Chemical Reaction

A process in which a new substance is formed, indicated by a color change, gas production, energy change, or solid precipitate formation.

Exothermic Reaction

A reaction that releases heat to the surroundings.

Endothermic Reaction

A reaction that absorbs heat energy from the surroundings, causing the temperature to decrease.

Compound

Two or more elements chemically joined together.

Mixture

Two or more substances physically mixed but not chemically joined, and easily separated.

Diatomic Element

Two atoms of the same element joined together (e.g., H2, N2, O2).

Covalent Molecule

A group of non-metal atoms joined together.

Formula

The simplest ratio of atoms in a molecule.

Prefix

A word added to the beginning of another word; in chemistry, prefixes indicate the number of atoms of an element in a compound (e.g., mono, di, tri).

Reaction Rate

The speed at which reactants are converted into products in a chemical reaction.

Reactants

Chemicals present at the start of a reaction.

Products

Substances produced at the end of a reaction.

Catalyst

A substance that speeds up a chemical reaction without being used up itself.

Atom

The smallest particle of an element, containing protons, neutrons, and electrons.

Atomic Number

The number of protons in the nucleus of an atom, unique to each element.

Mass Number

The total number of protons and neutrons in the nucleus of an atom.

Isotopes

Atoms of the same element with the same atomic number but different mass numbers due to varying numbers of neutrons.

Relative Atomic Mass

The average mass of the atoms of an element, considering the number, mass, and abundance of its isotopes.

Covalent Bond

The attraction of two positive nuclei for a shared pair of electrons.

Ionic Compounds

Compounds formed between metal and non-metal elements where electrons are transferred from one atom to the other.

Ions

Atoms that have lost or gained electrons, resulting in a positive or negative charge.

Valency

The combining power of an atom; in ionic compounds, it's the charge on the ion.

Ionic Lattice

A structure in which ionic solids are held together by strong electrostatic attractions between positive and negative ions.

Electrolysis

The decomposition of an ionic compound into its elements using electricity.

Acids

Substances with a pH less than 7, containing more H+ ions than OH- ions.

Bases

Substances that can neutralize an acid; typical bases include metal oxides, metal carbonates, and metal hydroxides.

Alkalis

Bases that dissolve in water, having a pH greater than 7 and containing more OH- ions than H+ ions.

Neutralisation Reaction

A reaction in which a base reacts with an acid to form water and a salt.

Spectator Ions

Ions that remain unchanged during a chemical reaction and can be omitted from the net ionic equation.

Standard Solution

A solution of accurately known concentration.

Volumetric Titrations

A laboratory method for determining the concentration of a solution by accurately measuring the volumes used in a neutralisation reaction.