CH1012
L1 /
‹#›
L1 /
11
EMPIRICAL FORMULAE
Elemental analysis
eg. to work out an empirical formula from
analytical data : C 55.15%, H 10.41% N 16.06%
i) find oxygen : 100 - (C% +H%+N%) = O%
eg. to work out an empirical formula from
analytical data : C 55.15%, H 10.41% N 16.06%
i) find oxygen : 100 - (C% +H%+N%) = O%
ii) find atom
ratios:
C% H%
N% O%
55.15 /12.01 10.41 /1.01 16.06 /14.00 18.37 /16.00
55.15 /12.01 10.41 /1.01 16.06 /14.00 18.37 /16.00
iii) divide all values
by the smallest number
4.590 10.327 1.147 1.148
4.590 10.327 1.147 1.148
4
9 1 1
iv) Empirical formula : C4H9N1O1
calculate M= (4x12)+(9x1)+(1x14)+(1x16)
=87
compare with mass
spec. [M]+ = 87
