ZIMSEC O Level Combined Science Notes: Experiment: making ethanol
Aim: To make ethanol by fermenting glucose
Materials: conical flask/plastic bottle, cork, glass/rubber tube,lime water, 5% glucose solution, yeast, mealie meal
Method
- Add about 50cm3 of the 5% glucose solution into the flask
- Add a spatula of yeast/mix mealie meal with water and add to yeast
- Cork the flask and alow the end of the tube to dip in lime water in the test tube as shown in the diagram above
- Leave in a warm place for a few days
- Observe the lime water
- Smell the contents of the flask
Results and Observations
- The lime water turns milky after a few days
- The contents of the flask have a pungent smell typical of alcohol/ethanol
Conclusion
- The glucose solution is turned into an ethanol solution by the fermentation process
NB The concentration of the alcohol can be increased via the distillation process
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