Question

synthesis of Ethanol by fermentation

Describe and explain the possible effect on your results of follo ing experimental variations, (a) You forgot to add Pasteur's the fractional distillation, you continued to collect distillate until the temperature reached 98°C. (c) Unknown to someone reset the automatic pipet for the density determination 190 .

Answer 1

(a) If you forgot to add the pasteur's salts the medium become acid with the time, so too much acidity can denature the proteins in yeast and the % ethanol will be low.

b) At 98 oC the fraction is practically water, so if you take that fraction in your calculatios it will low the % yield of ethanol

c) If the pipet was reseted and another volume is taken, you just have only to take that new volume and the mass will be proportional to it. The only problem is present when you take too much low volumes which increase error.