Analysing Substances

Question 1

How can elements and compounds be detected and identified

What are 4 qualities of this method

Answer 1

Instrumental methods
Accurate sensitive and rapid
Can detect a small sample

Question 2

What is chemical analysis used for

Answer 2

Identifying additives in food such as artificial colours on paper chromatography

Question 3

Give two examples of instrumental methods

Answer 3

Gas chromatography linked to mass spectroscopy

Paper chromatography

Question 4

Give 3 qualities of gas chromatography

Answer 4

Allows the separation of a mixture of compounds

The time taken for a substance to travel through column helps identify the substance

The output can be linked to mass spectrometer which can be used to identify substances leaving end of column

Question 5

List the process of GC

Answer 5

Different substances carried by gas travel through column packed with solid material at different speeds- cause to become separated

Number of peaks on the output of gas chromatograph shows number of compounds present.

Position of peaks on output indicates retention time

A mass spectrometer is then used to identify substances very quick and accurately as well as in small quantities

Question 6

What can the mass spectrometer also give

Answer 6

Relative molecular mass of each substance separated- given by molecular ion peak