Practicals 👩‍🔬

Question 1

Investigation on the effect of pH on amylase

Answer 1

1. Add amylase to starch solution
2. Add drops of iodine to the amylase solution
3. record the time when the iodine no longer turns the solution blue
4. Repeat with solutions at different pHs

Question 2

Test for calorie content in foods

Answer 2

1. Burn a known mass of food under a boiling tube filled with a known volume of water.
2. Calculate the change in temperature of water

Question 3

Test for lipids

Answer 3

1. To test for lipids add ethanol and water and shake

2. If lipids are present a white emulsion will form

Question 4

Test for reducing sugars

Answer 4

1. To test for sugar add Benedicks and heat for about two minutes
2. It will turn any of green yellow or red if sugar is present.
3. The colour depends on the concentration.

Question 5

Test for starch

Answer 5

1. To test for starch add iodine solution

2. It will turn blue-black is starch is present

Question 6

Test for protein

Answer 6

1. To test for proteins add buiret solution

2. It will turn mauve or purple if proteins are present

Question 7

Investigating osmosis

Answer 7

1. Cut discs of raw potato and measure the mass of each disc
2. Put the discs in concentration of sugar or salt solution
3. After 30 Minutes in solution, measure the mass of each potato disc
4. Using the initial mass and final mass of each potato disc calculate the change in mass for the discs in different solutions