Chemical Analysis and Instrumental Methods Flashcards
Artificial colours can be separated using what?
Paper Chromatography.
Food colouring may contain what?
One dye.
Mixture of dyes.
First step in paper chromatography?
Extract the colour from a food sample by placing in in a small cup with a few drops of solvent.
What can the solvent be in paper chromatography?
Water.
Ethanol.
Salt water.
Second step in paper chromatography?
Put spots of the coloured solution on a pencil baseline on filter paper.
Why don’t you use pen in paper chromatography?
It might dissolve in the solvent and confuse everything.
Third step in paper chromatography?
Roll the sheet up and put it in a beaker with some solvent.
During paper chromatography make sure the baseline is what?
Above the level of the solvent.
Fourth step in paper chromatography>
Solvent seeps up the paper.
Taking dyes with it.
In paper chromatography what do different dyes do?
Form spots in different places.
A chromatogram with four spots means what?
It has at least 4 dyes, not exactly 4 dyes.
One dye can’t what?
Split into 2 dyes.
Machines can also do what?
Analyse unknown substances.
You can identify what using instrumental methods?
Elements and compounds.
Name 3 advantages of using machines?
Very sensitive.
Very Fast.
Very accurate.
Why is it good that machines are sensitive?
They can detect the tiniest amounts of substances.
What can gas chromatography do?
Separate out a mixture of compounds and help identify the substance present.
In gas chromatography gas is used to carry substances through what?
A column packed with a solid material.
Why do the substances travel through the tube at different speeds?
So they become separated.
The time it takes to reach the detector is called what?
The retention time.
The retention time can be used for what?
Help identify the substances.
The recorder draws what?
A gas chromatography.
The number of peaks shows what?
Number of different compounds in the sample.
The position of the peaks shows what?
The retention time of each substance.
The gas chromatography column can also be linked to what?
A mass spectrometer.
The gas chromatography column can also be linked to the mass spectrometer, this process is known as what?
GC-MS.
The process GC-MS can identify what?
Substances leaving the column very accurately.
What else can you work out from the graph?
The relative molecular mass of each substance.
How can you find the relative molecular mass?
Read off the molecular ion peak.
