chemical formulae Flashcards
1
Q
how do you work out chemical formulae if it is a metal or singular non-metal?
A
work out charges on each ion: groups 1-3 go up in positivity +1-3
groups 5-7 go down in negativity -3-1
2
Q
how do you work out chemical formulae if it is 2 or more non-metals?
A
work out how many covalent bonds each element must form:
using the group number work out number of bonds, for example if it is group for you take it away from 8 to equal 4, if it is group 6 you take it away from 8 and you get 2
3
Q
how do you work out percentage yield?
A
percentage yield = (actual value/theoretical value) x 100
4
Q
how do you work out number of moles?
A
mass/ relative atomic mass
5
Q
how do you work out number of moles in gas?
A
moles gas = volume dm3/24
