Definitions Flashcards
Amount of substance
The quantity that has moles as its units, used as a way of counting atoms
What does anhydrous mean
Containing no water molecules
Mole
The amount of any substance containing as many elementary particles as there are carbon atoms in exactly 12g of the carbon-12 isotope
Avogadro Constant
6.02x10^23 per mole - the number of atoms per mole of carbon - 12
Relative atomic mass
The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of carbon 12
Relative Formula Mass
The weighted mean mass of the formula unit of a compound compared with 1/12 of the mass of an atom of carbon-12
Relative isotopic mass
The mass of an isotope compared with 1/12 of the mass of an atom of carbon-12
Relative Molecular mass
The weighted mean mass of a molecule of a compound compared with 1/12 of the mass of an atom of carbon -12
First ionisation energy
The energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions
Molar Mass
Ther mass per mole of a substance measured in grams per mole
Mass number
The sum of the number of protons and neutrons in the nucleus
Molecular Formula
A formula that shows the number and type of atoms of each element present in a molecule
Empirical Formula
The simplest whole-number ratio of atoms of each element in a compound
Hydrated
A crystalline compound containing water molecules
Water of crystallisation
Water molecules that are bonded into a crystallise structure of a compound
Second ionisation energy
The energy required to remove one electron from each ion in one mole of gaseous 1+ ions of an element to form one mole of gaseous 2+ ions
Standard Solution
A solution of known concentration
Concentration of a solution
The amount of solute, in moles, dissolved in each 1dm^3 of solution
Molar gas volume
The volume per mole of gas molecules at a stated temperature and pressure
How can you convert from dm^3 to m^3?
x10^-3
How to convert from cm cubed to m cubed
X10^-6
How to convert from kPa to Pa
x10^3
How to convert from °C to K
+273
Stoichiometry
The ratio of the amount, in moles, of each substance in a chemical reaction
Theoretical yield
The yield resulting from the complete conversion of reactants into products - in other words the maximum possible amount of product
Actual Yield
The amount of product obtained from a reaction
Percentage yield
Actual yield
————————————— X 100
Theoretical yield of product
Periodicity
A repeating trend in properties of the elements across each period of the periodic table
Limiting reagent
The reactant that is not in excess, which will be used up first and stop the reaction
Atom economy
A measure of how well atoms have been utilised - (sum of molar masses of desired products) /(sum of molar masses of all product) x100
Lone pair
An outer shell pair of electrons that is not involved in chemical bonding
What is a bond angle?
The angle between two bonds
Dipole
A separation in electrical charge so that one atom of a polar covalent bond, or one end of a polar molecule, has a small positive charge and the other has a small negative charge
Electronegativity
A measure of the attraction of a bonded atom for the pair of electrons in a covalent bond
Dipole-dipole force
An attractive force between permanent dipoles in neighbouring polar molecules
Polar molecule
A molecule with an overall dipole, having taking taken into account any dipoles across bonds and the shape of the molecule
Polyatomic ion
An ion containing more than one atom
Permanent dipole
A small charge difference that does not change across a bond, with positive and negative partial charges on the bonded atoms on the bonded atoms: the result of the bonded atoms having different electronegativities
Permanent dipole-dipole interactions
Attractive forces between the permanent dipole in different molecules
Dipole-dipole force
An attractive force between permanent dipoles in neighbouring polar molecules
What is a binary compound?
A compound which contains only two elements
What is a mass spectrum?
The output from a mass spectrometer that shows the different isotopes that make up an element
What is the function of a mass spectrometer?
It accurately determined the mass and abundance of separate atoms or molecules, helping us to identify them
