Chemical formulae, equations and calculations Flashcards
1
Q
How to calculate relative formula masses (including Mr) from relative atomic masses (Ar)
A
Add together Ar of all atoms in formula
e.g H2O = (2 x 1) + 16 = 18
2
Q
What is a mole
A
6.02 x 10^23 atoms
Unit for amount of subsance
3
Q
Understand how to carry out calculations involving mass, Ar and Mr
A
Mass/Mr = Number of moles
4
Q
How to calculate percentage by mass of element in compound
A
Relative atomic mass x how many
———————————————— x 100
Relative Formula mass
5
Q
How to calculate percentage yield
A
Actual/theoretical x 100
