Chemical tests 2.1.2 (q)

Question 1

what is the test for proteins?

Answer 1

biuret test

Question 2

outline biuret test

Answer 2

add Biuret solution

positive result would show purple solution

negative result would show blue solution

Question 3

what is the test for starch?

Answer 3

the iodine test

Question 4

outline iodine test

Answer 4

add iodine solution

positive result would show blue-black solution

negative result would show orange-brown solution

Question 5

what is the test for lipids?

Answer 5

emulsion test

Question 6

outline the emulsion test

Answer 6

add ethanol and ice and shake

positive result would show emulsion (milky solution)

negative result would stay clear

Question 7

what is the test for sugars?

Answer 7

Benedict’s test

Question 8

outline test for reducing sugar

Answer 8

add Benedicts solution
heat in water bath

positive result would show a brick-red precipitate

negative result would stay blue

Question 9

colour changes for a positive Benedict’s test

Answer 9

green
to
yellow
to
orange
to
brick red

Question 10

outline test for non-reducing sugar

Answer 10

do normal Benedict’s test and you should get a negative result of a blue solution

heat solution with HCl and then neutralise with sodium hydrogencarbonate

heat with Benedict’s solution again

positive result would show brick-red precipitate

negative result would remain blue solution

Question 11

how are strips used for glucose?

Answer 11

dipped in solution
colour change observed

colour compared with a chart to tell you the concentrations of glucose