1.3 formulae, equations, moles Flashcards
a What is an atom?
a basic unit of a chemical element, with a nucleus made of protons + neutrons and electrons orbiting in shells
a What is an element?
an atom with a certain number of protons
a What is an ion?
an atom that has lost or gained electrons
a What is a molecule?
a group of atoms bonded together
a What is a compound?
a substance made of two or more elements chemically bonded together
a What is an empirical formula?
the smallest whole-number ratio of elements within a compound
a What is a molecular formula?
the number of elements in a compound displayed as e.g. C2H4
a What is a structural formula?
a molecule displayed in groups e.g. CH2 = CH2
a What is a displayed formula?
a molecule drawn showing all bonds as lines
b How do you construct an ionic equation?
write out all ions + non-aqueous compounds
cross out those that are the same either side (spectator ions)
c What is RAM?
a weighted average of the masses of isotopes of an element relative to 1/12 of a C-12 atom
c What is molar mass?
the mass of one mole of a substance, measured in g/mol
d How can you calculate concentration? (given moles and volume)
mol/vol
d How can you calculate the moles? (given mass and RFM)
moles = mass/RFM
f How can you calculate volume? (given moles)
vol in dm3 = mol/24
