Module 1 Atoms and reactions
UNIT 1 Atoms. Bonds and Groups
- Created by: Parmz
- Created on: 13-03-13 20:59
Isotopes
Are atoms of the same element with different numbers of neutrons.
Atomic number (proton)
Is the number of protons in the nucleus of an atom.
Mass number (nucleon)
is the number of particles (protons and neutrons) in the nucleus.
Ion
Positively or negatively charged atom.
Relative Isotopic Mass
is the mass of an atom of an isotope compared with one-twelfth of the mass of an atom of carbon-12.
Relative Atomic Mass
Is the weighted mean mass of an atom compared with one twelfth of the mass of an atom of carbon-12.
Relative Molecular Mass
Is the weighted mean mass of a molecule compared with one-twelfth of the mass of an atom of carbon-12.
Relative Formula Mass
Is the weighted mean mass of a formula unit compared with one-twelfth of the mass of an atom of carbon-12.
Avogadro constant
Is the number of atoms per mole of the carbon-12 isotope (6.02 x 10,23 mol -1)
Mole
Is the amount of any substance containing as many particles as there are carbon atoms in exactly 12g of the carbon-12 isotope.
Molar Mass
is the mass per mole of a substance. Units: g mol-1
Empirical Formula
Is the simplest whole-number ratio of atoms of each element present in a compound.
Molecule
Is a small group of atoms held together by covalent bonds.
Molecular Formula
Is the actual number of atoms of each element in a molecule.
Molar Volume
Is the volume per mole of a gas. Units: dm-3 mol-1.
Room temperature approx. 24.0dm3 mol-1
Concentration
The amount of solute in mol, dissolved per 1dm3 (1000cm3) of solution.
Standard solution
Is a solution of known concentration. (Usually used in titrations)
Species
Is any type of particle that takes part in a chemical reaction.
Stoichiometry
Is the molar relationship between the relative quantites of substances taking part in a reaction.
Acid
Is a species that is a proton donor
Base
Is a species that is a proton acceptor
Alkali
Is a type of base that dissolves in water forming hydroxide ions
Salt
Is any chemical compound formed from an acid when a H+ ion from the acid has been replaced by a metal ion or another positive ion, such as the ammonium ion.
Cation - positively charged ion
Anion - negatively charged ion
Hydrated
Contains water molecules
Anhydrous
Contains no water molecules
Water of crystallisation
Refers to water molecules that forman essential part of the crystalline structure of a compound.
Oxidation number
Is a measure of the number of electrons that an atom uses to bond with atoms of another elements.
Oxidation
Loss of electrons or an increase in oxidation number
Reduction
Gain of electrons or a decrease in oxidation number
Redox Reaction
A reaction where both oxidation and reduction take place.
Reducing Agent
Is a reagent that reduces (adds electron to) another species.
Oxidising Agent
Is a reagent that oxidises (takes electrons from) another species.
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