Define a mole
Unit for amount of substance: the amount of chemical species found in 12g of carbon-12
What is Avogadro’s constant?
Number of atoms in exactly 12g of carbon-12.
6.02 x 10^23
Define molar mass
Mass of 1 mole of the substance in g/mol
Define relative molecular mass
Average mass of a molecule relative to 1/12 mass of carbon-12 atom
Define empirical formula
Smallest whole number ratio of atoms of each element in a compound
Define molecular formula
Actual number of atoms of each element in a molecule
Define spectator ion
Ions that do not take part in the reaction
What is a hydrate?
A compound that has waters of crystallisation
What is a standard solution?
One with an accurately known concentration
What is mass concentration?
Mass of solute per volume unit of solution - gdm^-3
What is molar concentration?
Moles of solute per volume of solution - moldm^-3
What is a primary standard?
A substance used for preparation of a standard solution
What is Avogadro’s law?
Provided the conditions of temperature and pressure are the same, equal volumes of gas contain the same number of molecules
What is molar volume?
Volume of 1 mole of gas
What is a displacement reaction?
A more reactive element reacts to take the place of a less reactive element in a compound
What is a precipitation reaction?
One that produces an insoluble solid (precipitate)
What is an error?
A discrepancy between the value obtained in an experiment and the actual value
What is precision?
Reference to how close each value is to each other obtained in an experiment
What is accuracy?
Reference to how close obtained values are to the actual value
What are concordant results?
Results that lie close to each other, usually titrates that lie within 0.20cm^3 (+/- 0.10cm^3)
What is a margin of error?
The range in which the true values could lie
What are random errors?
They occur when conditions are varied in an unpredictable manner
What are systematic errors?
Errors which are constant when you repeat an experiment, usually result of an apparatus used
What is the equation for percentage uncertainty?
(Actual yield / theoretical yield) x 100 (%)
What is atom economy?
Measure of the proportion of atoms that become part of the desired product in the balanced chemical equation
What is the equation for atom economy?
(Mr of desired product / total Mr of all products) x 100 (%)
What does each letter of the pv = nRT equation represent?
p = pressure (Pa) v = volume (m^3) n = moles (mol) R = ideal gas constant: 8.314 T = temperature (k)