3.2 determination of formulae Flashcards
1
Q
Define:
Molecular formulae
A
the number of atoms of each element in a molecule
the actual….
2
Q
Define:
Empirical formulae
A
the simplest whole number ratio of atoms of each element in a compound
3
Q
when do we use
Relative molecular mass Mr
A
compounds that exsist as simple molecules eg H20 and Co2
Mr(H2O)=(1.0x2)+16=18.0
4
Q
When do we use
Relative formula mass
A
compounds that exsist as giant structures eg all ionic structures
NaCl=23.0+35.5=58.5
5
Q
Define
Water of crystalisation
A
water molecules that area part of the crystaline structure of hyrated salts
shown in an equation with a big dot
eg CuSO4.5H20
6
Q
What are the two assumptions we make when calculating experimental formulae of a hydrated salt
A
A1. All the water has been lost
A2. No futher decompostion has taken place
