This week you will examine a chemical test you have done before in greater detail. In the first part of this lab you will determine the sensitivity of the Benedict's test. The Benedict's test tests for the presence of aldehydes and in this case the aldehyde we will be testing for is glucose. You will prepare only solutions A, C and E using serial dilation. Recall that this is the same method you used in experiment 9. Any color change from blue is a positive test for the Benedict's test. The color change is due to conversion of the the blue Cu++ ion to the red Cu+ ion. A positive test may appear anywhere between red and green or purple. Again, any change in color is due to the formation of Cu+ and is therefore a positive result.

The second part of this lab is the testing of materials such as a banana and soft drink for glucose and starch. The starch test is done on a spot plate by adding a drop of I2/KI solution to the unknown. A blue color indicates a positive test. This is a very straight forward lab because you have already done most of the chemical tests in this lab, so plan to finish early.