Vitamin C Core Practical Write Up Sheet
Aim
To investigate the vitamin C content of different fruit juices.
Hypotheses
Null Hypothesis: Different fruit juices will have the same vitamin C content.
Alternative Hypothesis: Different fruit juices will have different vitamin C contents.
Equipment
Apparatus
Justification of apparatus
Burette
To accurately measure the volume of the fruit juice added to the DCPIP solution to decolourise it.
0.1% DCPIP solution
As a test to see when it has been reduced by the vitamin C as it turns colourless when reduced. (Acts as an indicator)
1% vitamin C solution
As a measure of comparison, so we can compare the vitamin C content of the fruit juices with it.
A range of fruit juices
To test the vitamin C content in fruit juices and to compare the different fruit juice contents.
250ml and 100ml beakers
To transport different solutions around the classroom.
Syringe
To accurately measure 1cm3 of the DCPIP solution.
Method
Measure 1cm3 of the 0.1% DCPIP solution using the syringe and put it into a 100ml beaker. Pour some of the 1% vitamin solution C into a 200ml beaker, fill the burette with this solution and record the start volume. Add 1% vitamin C solution drop by drop to the 1% DCPIP solution while swirling the beaker. Continue adding drops of the 1% vitamin C solution until until the DCPIP solution has been decolourised; it turns from a blue colour to colourless. Record the end volume and then calculate the exact volume of 1% vitamin C solution needed to decolourise the 0.1% DCPIP solution by taking away the start volume from the end volume. Repeat this method five times and then calculate the mean result by adding the five volumes up and then diving this answer by five excluding any anomalies. Repeat this procedure with the pineapple juice, orange juice, cranberry juice and the grapefruit juice. The 1% vitamin C solution contains 10 mg of vitamin C in 1.0 cm3. Calculate the mass of vitamin C that is...