topic 3 - quantitive chemistry: use of amount of substance in relation to masses of pure substances Flashcards
What are chemical amounts measured in?
Moles.
What is the symbol for the unit mole?
mol
What is the mass of one mole of a substance in grams numerically equal to?
The substance’s relative formula mass.
What does one mole of a substance contain the same number of the stated particles, atoms, ions or molecules as?
One mole of any other substance.
What does the Avagadro constant tell us?
The number of atoms, ions or molecules in one mole of a given substance.
What is the value of the Avagadro constant?
6.02 x 10^23
What is the formula which links moles, relative formula mass and mass.
mass = moles x relative formula mass
OR
moles = mass/relative formula mass
In a chemical reaction involving two reactants, why is it common to use an excess of one reactant?
To ensure all the other reactant is used.
What is the reactant that is completely used up in a chemial reaction called?
The limiting reactant.
What does a limiting reactant limit?
The amount of product that can be made.
What can the concentration of a solution be measured in?
Mass per given volume (e.g. grams per dm^3).
Which two ways can the concentration of a solution be increased?
- increase the mass of the solute
* decrease the volume of the solution
What is the equation which links concentration, mass and volume?
concentration = mass/volume
