Fun with phytoliths, part 1
|Weighing out: the container is zeroed and the exact weight of the sample recorded|
|Minor/no fizzing with HCl - not much carbonate|
CaCO3(s) + 2 HCl(aq) --> CaCl2(aq) + CO2(g) + H2O(l)
These samples are from cultural layers in the Baltic, and so the amount of carbonate in them is fairly small. You can see a few bubbles on the sample second from the bottom - if the samples were rich in carbonates, they would all be very bubbly as the acid reacts with the carbonates to produce carbon dioxide. Sometimes they fizz so much the bubbles come all the way up the tube. After the fizzing has stopped, the acid is diluted by adding some distilled water, then removed by centrifuging the sample. It's a good idea to rinse the samples a couple more times to make sure all the acid is gone.
|Centrifuge - don't forget to balance|
Check back soon for the next thrilling installment: Stage 2 - removal of clays!