[audienne]

Had laboratory experiment to determine moisture on food products. Put cooking oil 2 gr inside oven dried for 1.5 hours which was set up at 105 C. After 1.5 hour, I did calculation and calculation showed that 78% of oil consist of moisture?

I am cracking my head because based on my knowledge that cooking oil should have almost zero moisture. Why the oil evaporated ? I just cant seem the explanation everywhere. I assume it is something to do with free and bound water and volatile component. But then y the oil has water? which volatile component?

Help please

[enahs]

Uhh yeah, that seems way off.

What kind of oil was it?

Show your data and calculations (neatly), maybe you did something wrong.

[audienne]

Weight of crucible (in g)…... (a)                                     44.56
Weight of crucible and sample (in g)…. (b)                       46
Weight of sample before heating (in g)….. (x=b-a)              1.99
Weight of crucible +sample after heating (in g)……….c        45.1
Weight of sample after heating (in g)…. (y=c-a)                 0.54
Moisture content (in g)….. (x-y)                                      1.45
% moisture content…..  (x-y)/x *100                              72.86

the oil was put on crucible and heated inside oven (oven dried) for 1.5 hours at 105C

The oil is cooking oil, no idea whether it is canola, olive or other type. The tutor did not tell us.

[nj_bartel]

Weight of crucible (in g)…... (a)                                     44.56
Weight of crucible and sample (in g)…. (b)                       46
Weight of sample before heating (in g)….. (x=b-a)              1.99
Weight of crucible +sample after heating (in g)……….c        45.1
Weight of sample after heating (in g)…. (y=c-a)                 0.54
Moisture content (in g)….. (x-y)                                      1.45
% moisture content…..  (x-y)/x *100                              72.86

the oil was put on crucible and heated inside oven (oven dried) for 1.5 hours at 105C

The oil is cooking oil, no idea whether it is canola, olive or other type. The tutor did not tell us.

46g - 44.56g =/= 1.99g

The water content still comes out way too high, especially since you're doing it by mass, but there's one error.

[audienne]

Yeah i realised the water content is way too high.

 1.99g is the mass of the oil before it evaporated. The mass of oil after it was heated was 0.54g

I do realise that oil can evaporate but as u said the water is way too high. What could cause the error? Can the oven dried method cause the error? But how?

[nj_bartel]

I'm saying you subtracted wrong determining the mass of the oil preheating.  I don't know what could have happened experimentally.

[agrobert]

I'm saying you subtracted wrong determining the mass of the oil preheating.  I don't know what could have happened experimentally.

46-44.56=1.44 g