What can happen if you have heated glass next to cool or cold water?
1 answer:
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Answer:
Paper chromatography is a basic technique of chromatography. It consist in the separation of the mixe components using a solvent.
Explanation:
Paper chromatography is a basic technique of chromatography. It consists in the separation of the mixed components using a solvent.
Paper chromatography consists of put some dot of the mix using a glass capillary into a specialized paper, generally made of cellulose, this is called a stationary phase.
Then you put this paper into a camera of glass named, chromatography camera, where previously contain a solvent. The solvent also know as a mobile phase, the type can be defined before the test and involves a study of the kind of the mix, and the compound you want to separate.
The chromatography camera has to be closed all the time during the test, and you can't move at all because the movement of the solvent can alternate the result.
Very often, the solution of the solvent is a mix of different liquid substances with different polarities.
When the stationary phase put into the camera, the solvent starts to move up over the paper, until the separation of the compounds is observable.
the Rf is a value who relates the move of the mobile phase with the move of the distance traveled by the substance tested.
To undersant the paper chromatography, you can watch the images attached.
The first is an image of the chromatography camera.
The second one is an image of a cellulose paper after the chromatography is done. You can watch the dots who indicates the traveling of the compound across the paper.
The third one can show you the evolutions of paper chromatography, from the beginning to the end.
To calculate the Rf value you have to use the equation:
Rf = distance traveled by the substance/distance traveled by the solvent/
<u>Rf = 52mm/81mm =0.64</u>
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Answer:
In the Lewis structure of P4 there are 6 bonding pairs and 4 lone pairs of electrons.
Explanation:
The structure of tetrahedral molecule of P4 is provided below.
Each phosphorus atom has 5 valence electrons out of which 3 electrons involve in bonding and the rest 2 electrons exist as a lone pair that does not involve in bonding.Hence each phosphorus atom has one lone pair.In P4 molecule there are phosphorus atoms and hence 4 lone pairs in total.
As you can see in the figure, each phosphorus atom is bonded to the other three atoms.A bond is formed when two atoms share one electron each and the pair is called bonding pair.
From the figure we can see that there are 6 bonds in total.Each bond consist of one bonding pair of electrons and hence in total there are 6 bonding pairs of electrons.
Hence in a P4 molecule there are six bonding pairs and 4 lone pairs of electrons.
