Chemical Analysis and Instrumental Methods

Question 1

Artificial colours can be separated using what?

Answer 1

Paper Chromatography.

Question 2

Food colouring may contain what?

Answer 2

One dye.

Mixture of dyes.

Question 3

First step in paper chromatography?

Answer 3

Extract the colour from a food sample by placing in in a small cup with a few drops of solvent.

Question 4

What can the solvent be in paper chromatography?

Answer 4

Water.
Ethanol.
Salt water.

Question 5

Second step in paper chromatography?

Answer 5

Put spots of the coloured solution on a pencil baseline on filter paper.

Question 6

Why don’t you use pen in paper chromatography?

Answer 6

It might dissolve in the solvent and confuse everything.

Question 7

Third step in paper chromatography?

Answer 7

Roll the sheet up and put it in a beaker with some solvent.

Question 8

During paper chromatography make sure the baseline is what?

Answer 8

Above the level of the solvent.

Question 9

Fourth step in paper chromatography>

Answer 9

Solvent seeps up the paper.

Taking dyes with it.

Question 10

In paper chromatography what do different dyes do?

Answer 10

Form spots in different places.

Question 11

A chromatogram with four spots means what?

Answer 11

It has at least 4 dyes, not exactly 4 dyes.

Question 12

One dye can’t what?

Answer 12

Split into 2 dyes.

Question 13

Machines can also do what?

Answer 13

Analyse unknown substances.

Question 14

You can identify what using instrumental methods?

Answer 14

Elements and compounds.

Question 15

Name 3 advantages of using machines?

Answer 15

Very sensitive.
Very Fast.
Very accurate.

Question 16

Why is it good that machines are sensitive?

Answer 16

They can detect the tiniest amounts of substances.

Question 17

What can gas chromatography do?

Answer 17

Separate out a mixture of compounds and help identify the substance present.

Question 18

In gas chromatography gas is used to carry substances through what?

Answer 18

A column packed with a solid material.

Question 19

Why do the substances travel through the tube at different speeds?

Answer 19

So they become separated.

Question 20

The time it takes to reach the detector is called what?

Answer 20

The retention time.

Question 21

The retention time can be used for what?

Answer 21

Help identify the substances.

Question 22

The recorder draws what?

Answer 22

A gas chromatography.

Question 23

The number of peaks shows what?

Answer 23

Number of different compounds in the sample.

Question 24

The position of the peaks shows what?

Answer 24

The retention time of each substance.

Question 25

The gas chromatography column can also be linked to what?

Answer 25

A mass spectrometer.

Question 26

The gas chromatography column can also be linked to the mass spectrometer, this process is known as what?

Answer 26

GC-MS.

Question 27

The process GC-MS can identify what?

Answer 27

Substances leaving the column very accurately.

Question 28

What else can you work out from the graph?

Answer 28

The relative molecular mass of each substance.

Question 29

How can you find the relative molecular mass?

Answer 29

Read off the molecular ion peak.