Activity 11.3, Book page 143
A1 – It is important to boil water to drive off any dissolved air.
A2 – The sugar solution must be cooled because if it is hot, yeast would die and we won’t be able to do the experiment.
A3 – The liquid paraffin is used to separate the yeast in the cooles sugar solution, from the air in the test tube.
A4 – In the test tube containing living yeast, the lime water will turn cloudy as the yeast releases carbon dioxide while respairing. However, in the test tube were the yeast is dead, and not respairing, the lime water will remain clear.
A5 – The substance we would expect to find in the sugar solution containing living yeast, is alcohol as yeast respire anaerobically and they release this one while they are respairing.