F321-The Mole Flashcards
Define Avogadro’s Constant
The number of particles per one mole of a substance (6.02x10^23)
Define Mole
The amount of substance containing as many particles as there are carbon atoms in exactly 12g of C-12
How do you work out the number of particles present in a substance?
Particles = Moles x Avogadro’s Constant
How do you find out the number of atoms present in a substance?
Work out the number of particles(molecules) and then multiply that by the number of elements in the compound
Define Molar Mass
The mass, in g, per mole of a substance (gmol-1)
How do you work out the moles of something?
Moles = mass/ M(molar mass)
How do you work out the moles in a gas?
Moles = vol.gas/24(if dm) or 24,000 (if cm)
How do you work out the moles in a solution?
Moles = CxV (if dm)
Or CxV/1000 (if cm)
How do you find out the moles of something with no information?
Find out the moles of a different compound in the equation & use stochiometry to find the moles
How do you find out the empirical formula of something?
Find the moles of each element, then divide each moles by the lowest value, this will give the ratio of the elements
Define Empirical Formula
The simplest whole number ratio of atoms of each element present in a compound
Define Molecular Formula
The actual number of atoms of each element in a molecule
How do you calculate the molecular formula?
Calculate the empirical formula, then divide the molar mass by the empirical mass. Then multiply the empirical formula by the answer.
Define Hydrated
When water of crystallisation is present in a crystal compound
Define Anhydrous
When all the waters of crystallisation have been removed from a compound
