Stoichiometry Flashcards
Stoichiometry “chemical arithmetic”
Stoichiometry is concerned with the relative amounts of reactants and products in a chemical reaction
what does stoichiometry allow
It allows us to weigh bulk quantities of reactants and products in chemical reactions, rather than having to weigh individual atoms and molecules
Chemical equations
Tells us about the ratio in which the reactants in a chemical reaction react to give products
True or false: chemical equations must be balanced
True
The mole
is the SI unit of the amount of substance
Define the mole
“the amount of substance that contains the same number of specified entities as there are atoms in exactly 12g of the carbon isotope 12^C”
1 mole of anything contains…
6.022 x 10^23 entities
Avagadros constant
6.02214078(18) x 10^23 mol-1
Molar mass
Molar mass (M) is the mass of 1 mole of a specified entity
Molar mass unit
M has a unit of g mol-1 (grams per mol)
Molar mass equation
M=m/n
Where can molar mass be found?
Molar mass values are obtained from tables
Mole relationships
Balanced chemical equations give mole relationships between all reactants and products
Limiting reagents
Sometimes, the reactants are not present in exact stoichiometric amounts. In these cases one reactant will be a limiting reagent.
Limiting reagent example
E.g. how many bicycles can be made from these parts (8 wheels, 10 frames). The wheels are the limiting reagents.
