Unit 3 Chemical Analysis

Question 1

What is chromatography used for how does it do this?

Answer 1

To separate substances in comped mixtures
By making use of difference in their polarity or molecular size

Question 2

What factors affect how far a sample travels?

Answer 2

The size or the polarity of the molecules involved
Large molecules move slowly whereas small molecules are more mobile
Polar molecules will be more strongly attracted to polar solvents, and so wld move further if a polar solvent was used as opposed to a non polar solvent

Question 3

What is a standard soloution?

Answer 3

A solution of accurately known concentrations

Question 4

What is meant by concordant results?

Answer 4

Volumes within 0.2cm3 are considered to be concorbant at higher

Question 5

In a titration what is meant by the end point?

Answer 5

Is the point at which the reaction is just complete

Question 6

In a titration why is a indicator used?

Answer 6

Changes colour showing the end point

Question 7

Describe how a burrete is used to begin a titration?

Answer 7

Rinse the bruette with the solution to be put in
Fill brunette above scale with solution
Filter funnel used shld be removed
Tap opend/some solution drained to ensure no air bubbles

Question 8

Why do some titrations not require indicator?

Answer 8

When using pottasium permanganate
As it is coloured and losses colour when it is reduced