chem ia (caffeine extraction) help with the error calculations

[artozprinter]

I am doing a chem ia on how the brewing temperature will affect the caffeine content within tea. I have done my experiment and all but I am having a hard time calculating my errors. So basically I used solvent extraction method to extract caffeine from tea with chloroform and then evaporated it. At last I was left with crude caffeine so i used its mass and the molar mass of standard caffeine to find the amount in mols. To find the errors do I just need to use the uncertainty of molar mass(0.001g) and the mass of crude caffeine (0.002g)? To prepare the tea solutions I have used water and tea bags. To get rid of the tannins (compounds that could be extracted with caffeine and affect the final mass) I used sodium carbonate. Do I need to find the uncertainties of water, tea bags and sodium carbonate for the error calculations? If so how am I supposed to do it, I know how to find the percentage error but how am I supposed to mix the all up and find the final error things? Like if sodium carbonate was not used, tannins would be also extracted with caffeine which would affect the value of mass that I am using the find the amount in mols. But does this really affect the uncertainty of caffeine mass? Pls help me I don't really understand these things