Chemical Analysis Flashcards Preview

Chemistry > Chemical Analysis > Flashcards

Flashcards in Chemical Analysis Deck (15):
1

What does a chromatogram with four spots mean?

A chromatograms with four spots means at least four dyes there could be five dyes with two of them making the spot in the same place however it can't be three days because one dye can't split into two spots

2

Name the 4 step method of chromatography

1) but if you drops of solvent into a small cup such as water

2) with a pen put coloured spots on a pencil baseline drawn on the filterpaper

3) Keep the baseline above the level of solvent when you place it in the beaker

4) The solvent seeps up the paper taking the dye with it, the different dyes from spots in different places

3

Other than chromatography what else can be used to analyse unknown substances?

Machines

4

Name three advantages of using machines to analyse unknown substances...

1) very sensitive they can detect even the tiniest amount of substances

2) very fast and tests can be automated

3) very accurate

5

What are the two types of chromatography?

-paper chromatography
-gas chromatography

6

What is gas chromatography used for?

Gas chromatography can be used to identify substances

7

What does Gas chromatography do?

Gas chromatography can separate out a mixture of compounds and help you identify the substances present

8

What is retention time?

The time substances take to reach the detector is called the retention time

9

How does gas chromatography work name the step-by-step process (4)

1) a gas is used to carry substances through the column packed with a solid material

2) The substances travel through the tube at different speeds so that they are separated

3) they reach the detector at different times (the retention time) which is used to help identify the substances

4) The recorder then draws a gas chromatograph the number of peaks show the number of different compounds in the sample

10

The gas chromatography column can also be linked to a mass spectrometer. What is this process called?

GC-MS

11

What can the process GC-MS do?

Can identify the substances leaving the column very accurately

12

What can you work out from a GC-MS graph?

The relative molecular mass of each of the substances from the graph it draws

13

Give three advantages of using instrumental methods to identify elements and compounds...

1) very fast

2). Very accurate

3) very sensitive

14

How can gas chromatography be used to work out the relative molecular mass of a substance?

A gas chromatography machine can be attached to a gas spectrometer (GC-MS) . The relative molecular mass of a substance can then be read off from the molecular ion Peak on the graph mass spectrometer draws

15

How can artificial colours be separated?

Using paper chromatography