Paper Chromatography Flashcards
What is paper chromatography?
Paper chromatography is a technique used to separate different coloured inks in a mixture, revealing the individual colours present.
What type of paper is used in paper chromatography, and why?
Special paper, similar to filter paper, is used because it allows the solvent to carry the ink particles up the paper, separating the different colours.
How does the chromatography process work?
A small drop of ink is placed on the special paper, which is then soaked in water. The water moves up the paper, carrying ink particles with it. Different colours in the ink separate out as they move at different speeds.
What is the resulting image on the paper called after chromatography?
The resulting image on the paper is called a chromatogram.
Why do the colours in the ink separate during chromatography?
The colours separate because the water (acting as the solvent) dissolves the ink, and different ink particles have varying solubilities. More soluble ink particles are carried further up the paper.
What determines how far an ink particle moves during chromatography?
The solubility of the ink determines how far it moves. The more soluble the ink, the further it travels on the paper.
What colours were observed in the chromatogram of the pens shown in the photo?
The chromatogram revealed different colours, such as green, black, and red, from the inks in the three pens.
Why can’t water be used to separate some inks, like permanent marker ink?
Permanent marker ink is not soluble in water. To separate such inks, a different solvent, like alcohol, is required.
How can a scientist compare different substances using chromatography?
A scientist can use a large piece of chromatography paper, placing spots of different items alongside each other, and allow the solvent to move up through all samples simultaneously in a large chromatography tank.
What does the chromatogram show when comparing different felt tip pens?
The chromatogram shows the colours present in a number of different felt tip pens, each separated according to its solubility.
Why do scientists use chromatography to study food dyes?
Scientists use chromatography to determine the dyes used in food, ensuring they know the exact composition of the dyes and whether they are safe for consumption.
What is the difference between pure substances and mixtures in food dyes?
Pure substances in food dyes contain only one component, while mixtures contain multiple substances. This distinction is crucial to assess whether the dyes might pose health risks.
How can you tell if a food dye is a pure substance using chromatography?
If a food dye results in only one spot on the chromatogram, it is a pure substance. If multiple spots appear, it indicates a mixture of substances.
Why is it important to know the exact substances used in food dyes?
It is important to know the exact substances to determine if they pose any health risks, such as being toxic or causing allergic reactions.
Which coloured substance in the food dyes is the most soluble?
The most soluble substance is the one that travels the furthest up the chromatography paper. In the diagram, it appears to be the blue substance.
