chapter 2 definitions

unified atomic mass unit

1/12 the mass of a carbon-12 atom

relative atomic mass

the weighted average of the masses of the molecules relative to 1/12 of the mass of a carbon-12 atom

relative isotopic mass

the mass of the isotope relative to 1/12 of the mass of a carbon-12 atom

relative molecular mass

weighted average of the masses of the molecules relative to 1/12 of the mass of a carbon-12 atom

relative formula mass

weighted average of the masses of the formula unit relative to 1/12 of the mass of a carbon-12 atom

mole

the amount of substance which contains the same number of particles as there are atoms in exactly 12g of carbon-12

Avogadro’s constant

the number of atoms in one mole of c12 which is 6.022×10²3

limiting reagent

the reactant that governs the maximum amount of product that can be formed (the smallest number of moles on the reagent side, using the mole ratio)

percentage yield

percentage of the theoretical yield achieved in practice ( this is how much product is made in an incomplete reaction, compared to how much could be made if the reaction was 100% complete )

percentage purity

the actual mass reacted/the initial mass used expressed as a percentage ( this is how pure as a percentage )

empirical formula

the simplest whole number ratio of atoms present in a substance

molecular formula

the actual number of atoms of each element presents in a substance.