Introduction

Glucose is very important in our daily lives. It gives us energy to carry out all of our activities. Cells in our bodies need glucose to respire and in the process release the energy we need. Glucose is also a type of carbohydrate. It has a chemical formula of C6H12O6 and is a monosaccharide reducing sugar (Kolej Mara Banting – Students’ Handbook for Biology HL Year 1). It is the simplest form of carbohydrate. In this experiment, sulphuric acid, H2SO4 and potassium permanganate, KMnO4 is added into glucose with different concentration and the time taken for the purple pink colour of potassium permanganate solution to change to colourless is recorded. This is because glucose donates electrons to the permanganate …show more content…

Variables Method to control
Independent
The concentration of glucose solutions
Use different concentration of glucose solutions which is 5%, 10%, 15%, 20%, 25% and 30%
Dependent
The time taken for the potassium permanganate solution to turn colourless, s
Observe and record the time taken for the potassium permanganate to turn colourless by using a stopwatch
Controlled
Volume of glucose solution in each boiling tube Volume of unknown glucose concentration; A, B and C Molarity of sulphuric acid

Volume of potassium permanganate solution in each boiling tube Volume of sulphuric acid in each boiling tube Size of beakers Fix the volume of glucose solution in each boiling tube which is 10 cm3 Fix the volume of unknown glucose concentration which is 10 cm3 Use the same molarity of sulphuric acid throughout the experiment which is 1M Fix the volume of potassium permanganate solution in each boiling tube which is 2 cm3 Fix the volume of sulphuric acid in each boiling tube which is 5 cm3 Use the same size of beaker which is 50 ml

Data collection and processing

i) Quantitative data

Mean, x ̅ = ∑x n

Standard deviation, S = √(∑(x-(x)) ̅ )2 √n

Trial

Concentration of glucose solution,
% Time taken for potassium permanganate solution to decolourise, s (±0.01) Mean, s (±0.01) ∑x 5 Standard deviation 1 2 3 4