Amount of a substance Flashcards
Empirical formula
The formula that represents the simplest whole number ratio of the atoms of each element in a compound
Molecular formula
the formula that gives the actual number of atoms of each element in one molecule of a compound
Spectator ions
Ions that are unchanged during a chemical reaction, that is, they do not take part in the reaction
The number of moles in a given volume of solution - equation
number of moles in solution n =
concentration c (mol dm-3) x volume V (cm3)
over 1000
percentage uncertainty
(uncertainty/vol) x 100
Atom economy
Describes the efficiency of a chemical reaction by comparing the total number of atoms in the product with the total number of atoms in the starting materials
(% atom economy =mass of desired product) x 100
over total mass of reactants
to reduce waste, find a use for the waste product
Percentage yield
The practical efficiency of the process
(actual mass / theoretical) x 100
How can you measure mass accurately?
- measure mass on 2 or 3 dp balance of a weighing bottle with required quantity of solid in it
- empty mass into reaction vessel
- reweigh empty weighing bottle
- first reading - mass of empty weighing bottle gives the exact mass added