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Chromatography

Chromatography is a set of techniques used to separate mixtures in a chemistry lab setting. The word chromatography means "color writing" and some of the first experiments in chromatography involved separating chlorophyll in plants.

649 Questions

How many colours does paper chromatography show?

They indicate the reaction with the solvent that the paper is dipped into.

In your experiment you should have had a few different spots on a base line. One spot should be what your unknown group. And other spots should be what you are trying to match it up with. You should then obtain a suitable solvent and dip the paper with the spots into the solvent. The spots on the base line will rise. You then should comapre your unknown group to your other groups and whichever group traveled the same distance as your unknown group you can match this group to your unknown and your unknown is equal to this group.

Sorry If that is confusing. It was confusing for me when I first did it.

See the related link for a good explanation.

What kind of mixtures are separated by gas-solid chromatography?

This method is commonly used to separate mixture of gasses.

Eg:

Substrate solutes

Molecular sieves SA &13* Gasses:H2, N2, O2, Ar, N2, CH4,CO;re

retains polar gasses CO2,

Which separation technique is used to separate the components of ink?

Any form of chromatography could be used to separate liquid ink.

Thin Layer Chromatography would be the simplest method:-

  1. Put a dot of the black ink around 1/4 of the way up a piece of filter paper.
  2. Place the filter paper in a buffer solution (usually a mixture of methanol and cyclohexane), but don't submerge the dot of ink.
  3. Wait for the buffer solution to get most of the way up the filter paper via absorption
  4. The black ink should have separated into several different colours that have moved different distances up the filter paper.

How is chromatography used in drug testing?

Chemists use liquid chromatography a complex of substances. They can use chromatography to analyze drugs and also test blood and urine samples. People use it to separate and purify different substances and chromatography can detect the presence of drugs in a person's blood.

What is the purpose of a chromatography lab?

Chromatography is used in blood to determine whether it is contaminated with alcohol and things like that. It can be also used to find out if cocaine etc. is in your urine and lead in water. This uses a colour chart to see what chemicals have been used and added up make a compound, then you can find out that it is alcohol, lead etc.

How does paper chromatography separate solutions?

As far as I'm aware, the solids have to be soluble in the mobile phase. When columning to purify in a synthetic lab anyway, you can see that partial solubility is ok to be able to get something off of a colum

How do people use chromatography in food testing?

There are many applications - from the characterisation of oils and fats (cis-trans and saturated/unsaturated etc..) to the analysis of traces of pesticides

and herbicides in fruit and vegetables. Nowadays the connection of a GC to a

mass spectrometer is relatively inexpensive and gives more specificity. Liquid chromatography extends the range of analytes such as many toxins (aflatoxins etc) which are unsuitable for GC and for example flavanoids in foods

What is void volume in chromatography?

bed volume= pie*r square*h

where, pie=3.14

r=radius of column

h=height of column

it is the total volume of column packed with the gel.

What jobs use affinity chromatography?

Chromatography is the use of specially formulated paper to test the pH of a solution. Jobs using chromatography include chemists, researchers, students, pharmaceutical technicians, aquarists, and pool maintenance personnel.

Why do you use a solvent in chromatography?

A solute will dissolve in a solvent when the attractive intermolecular forces between the molecules of the solvent and the molecules of the solute are greater than the attractive forces between one solute molecule and another. Thus the solute is effectively 'pulled apart' (on a molecular level at least) by the solvent and it's molecules become 'suspended' between the molecules of the solvent at which point the solute is said to be in solution or dissolved.

A hypothesis for paper chromatography?

A hypothesis for paper chromatography depends on what you are making the hypothesis on. A hypothesis for the speed of chromatography could be that you think the speed of the process can be changed depending on the type of paper, or whatever the stationary phase is, and the type of solvent being used.

Why does it make a difference if you mark chromatography paper with a pencil and not with a flair or ink pen?

Because the ink from the pen will run and smear during the chromatography but the pencil mark is not affected.

Why do you need to cover the beaker with a lid during paper chromatography?

During the development of a chromatogram, it is better to cover it with a beaker to prevent evaporation, which will affect the movement of the solute and solvent system. This will ensure that the chromatogram will develop properly.

What kind of paper is use for paper chromatography?

the apparatus are:petri dish , solvent such 3 parts of water and 1 part of methanol,thin paper ,samples either liquids samples or magic samples

by: 6a7awi

How does chromatography separate molecules?

The principle is based on equilibrium of the molecules between the mobile phase and the stationary phase. This will vary depending on the polarity of the substance, and the two phases. If the substance in more soluble in the mobile phase, it will travel further, and vice versa.

List of mixtures that can be separated by chromatography?

pen ink, marker ink, food coloring, dyes, felt pens, and colored pigments in plants

Did the spinach you tested contain different pigments Use your results to support your answer?

The pigments in the green leaf[spinach] contain 2 yellow green[chlorophyll b], faint yellow[carotenes] an yellow[xanthophyll]. In the red leaf[Moses in the Cradle or Poinsettia] the colors and pigments where yellow green[chlorophyll b], faint yellow[carotenes] and red[anthocyanins]. If you did the chromatography paper testing you will notice both leaves have chlorophyll in which indicates that both the red leaf and green leaf can photosyntehsize. [The red leaf also contains chlorophyll even though it is red and not green and absorbs enough light to photosynthesize.]

How does temperature affect chromatography?

The effect of temperature on retention characteristics in thin-layer chromatography (TLC) with low-volatility mobile phases (MP): It is shown that temperature variations in TLC in melts bring about variations in both the relative retention values and, in some cases, in the order of migration of the chromatographic zones across the layer.

Hope that helped :)