Compounds, formulae and equations Flashcards
What is an acid?
A compound which donates protons (H+ ions) when dissolved in an aqueous solution
What is an alkali?
A water soluble base. These accept protons (H+ ions), and release OH- ions when dissolved in aqueous solutions.
What is a base?
A proton acceptor, a compound which accepts H+ ions from another substance.
What is neutralisation?
A reaction between H+ and OH-, forming water. This may be a reaction between an acid and a base to form a salt (types of bases include carbonates, metal oxides and alkalis).
What is a strong acid?
An acid that completely dissociates in solution.
What is titration?
A technique used to determine the amount of one solution of a known concentration required to completely react with a known volume of another solution of unknown concentration.
What is a weak acid?
An acid that only partially dissociates in solution.
What is oxidation?
Increase in oxidation number/loss of electrons
What is reduction?
Decrease in oxidation number/gain of electrons
What is a redox reaction?
A reaction in which one element is oxidised and another is reduced
Define oxidation number
A number that represents the number of electrons lost or gained by an
atom of an element. A positive oxidation number indicates the loss of electrons.
Define isotopes
Atoms of the same element with the same number of protons and electrons but
different numbers of neutrons. Isotopes of an element have different masses.
What is a mass spectrometer?
An instrument which gives accurate information about relative isotopic
mass and the relative abundance of isotopes.
What is relative abundance?
The amount of one substance compared with another.
What is Relative Atomic Mass?
The weighted mean mass of an atom compared with 1/12th mass of
an atom of carbon-12.
What is relative isotopic mass?
The mass of an atom of an isotope compared with 1/12th mass of
an atom of carbon-12.
What is relative formula mass?
The mass of the formula unit of a compound with a giant structure.
Define relative molecular mass
The average mass of one molecule of an element or compound
compared to 1/12th the mass of an atom of carbon-12.
Define amount of substance
The quantity that has moles as its units, used as a way of counting
atoms. The amount of substance can be calculated using mass (n = m/M), gas volumes (n =
pV/(RT)) or solution volume and concentration (n = CV).
Define anhydrous
A crystalline compound containing no water.
What is atom economy?
A measure of the amount of starting materials that end up as useful
products. A high atom economy means a process is more sustainable as there is less waste
produced
Define empirical formula
The simplest whole number ratio of atoms of each element present in a
compound.
Define ‘hydrated’
A crystalline compound that contains water.
What is stoichiometry?
The relative quantities of substances in a reaction.
What is water of crystallisation?
The water molecules that form part of the crystalline structure of a compound.
Define molecular formula
The number and type of atoms of each element in a molecule.
