1 - Chemical Quantities Flashcards
Elements
The simplest chemicals - they cannot be broken down into simpler chemicals.
Compounds
Chemicals containing two or more elements chemically combined together.
Atom
The smallest particle of an element.
Molecule
A particle containing two or more atoms joined together chemically.
Ion
An atom, or a group of atoms, which has become electrically charged by the loss or gain of one or more electrons.
Molecular Formula
Shows the number of atoms of the different elements in one molecule of a compound.
Empirical Formula
Shows the simplest whole number ratio of the atoms of different elements in a compound.
Spectator Ions
Ions which take no part in a reaction.
Acids
Substances which donate hydrogen ions.
Bases
Substances which accept hydrogen ions.
Alkalis
Soluble bases.
Salts
Ionic compounds formed when an acid reacts with a base.
Relative molecular mass
The sum of the relative atomic masses of all the atoms in the molecular formula.
Relative formula mass
The sum of the relative atomic masses of all the atoms in the formula.
Molar mass
The mass of one mole of a chemical (g/mol).
Avogadro Constant
The number of atoms, molecules or formula units in one mole of any substance. It is 6.02 x 10^23.
Molar volume
The volume of 1 mole of a gas. At room temperature and pressure it is 24 dm^3/mol.
Actual yield
The mass of product obtained.
Theoretical yield
The mass of product obtained if the reaction goes according to the equation.
Percentage yield
(Actual yield / theoretical yield) x 100
Limiting reactant
A substance which is present in an amount which limits the theoretical yield.
Atom Economy
(Mass of atoms in desired product / mass of atoms in all reactants) x 100
