Core Practiacl 2 - vitamin c

Question 1

What was the aim of this experiment

Answer 1

Determining the concentration of vitamin c in various juices

Question 2

What is the method for CPAC 2 (vitamin C)

Answer 2

Measure out 1cm³ of DCPIP and place it into a beaker (with a pipette)

Using a funnel fill the burette with a fruit juice, and record the starting volume

Pipette until the DCPIP turns colourless , then record the volume on the burette

Calculate the total volume used in the titre

Repeat for each juice (and do repeats)

Question 3

How is the concentration of vitamin C calculated from the volume of fruit juice

Answer 3

Mass of vitamin C to decolourize DCPIP/ volume of juice

Question 4

What are some risks of the Vitamin C practicle

Answer 4

DCPIP irritates skin (wear gloves / safety goggles)

Glassware can be easily broken

Juice can spill

Question 5

What is the independent variable in the vitamin C CPAC

Answer 5

The fruit juice used

Question 6

What is the dependent variable in the vitamin C CPAC

Answer 6

Volume of juice needed to decolorize 1cm3 DCPIP

Question 7

What ate the conteol variables in the vitamin C CPAC

Answer 7

End point colour - (to ensure that the same volume of juice is added)

Same concentration of DCPIP - different concentrations will require different volumes of vitamin C to decolourize them

The amount of times the flask is shaken - to prevent the DCPIP from reacting with oxygen