Question

An experimental set-up shown below was used to investigate a certain process.

After 20 minutes, a student tested the sample from the boiling tube for starch and glucose and recorded the results as shown in the table below.

	Star	After 20 minutes
Start	Absent	Absent
Glucose	Absent	Present

1. Explain the presence of glucose in the water sample. 
2. What change occurred in the volume of liquid in:
   1. The boiling tube  
   2. The visking tube 

Answer 1

1. The visking tubing is semi permeable; and allows the small glucose molecules into boiling tube by diffusion;
2.  
   1. the volume of the liquid in the boiling tube decreased .
   2. The volume of the liquid in the visking tubing increased