what pressure will be needed to reduce the volume of 77.4 l of helium at 98.0 kpa to a volume of 60.0 l? 76 kpa 126 kpa
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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Explanation:
Atomic number is defined as the number of an element which represents total number of protons.
When an atom is neutral then it means it contains same number of protons and electrons.
On the other hand, atomic mass is defined as the sum of total number of protons and neutrons present in an atom.
Protons of every element remains fixed because it shows the identity of each element but if we change the number of neutrons then also identity of the atom will remain fixed. This is because changing the number of neutrons will not show any change in number of protons.
For example, and
are isotopes of hydrogen and they have same number of protons but different number of neutrons.
Thus, we can conclude that number of neutrons can vary without changing the identity of the element.