Elements, Compounds and Mixtures Flashcards
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What is an atom?
The smallest part of a substance that cannot be broken down further
What is a compound?
A group of two or more chemically bonded elements
What is a molecule?
A group of two or more chemically bonded atoms
What is a mixture?
A substance containing two or more different substances that are not chemically joined
What is simple distillation?
The process of purifying a liquid compound by heating it into a vapour that is then condensed back into a liquid
What is fractional distillation?
Same as simple distillation, but with a fractionating column with filled with glass bits
What is fractional distillation used for?
To separate multiple substances from a liquid compound
How does the fractionating column work?
Different liquids have different boiling points and therefore will cool any unwanted vapour back into liquids by condensing on the glass bits
What is filtration?
Process of separating solids and liquids using a paper filter
What is crystallisation?
evaporating water and leaving behind crystals
What is paper chromatography?
Substances distrubted between a stationary and mobile phase to discover the contents of substances
What is the stationary phase?
The phase when the water is trapped between the cellulose fibers of the paper
What does an RF value stand for?
Retention factor
What should the solvent be in paper chromatography?
Water or ethanol
In an exam, usually put water
True or False:
You should submerge the baseline and ink sample in the solvent
In a paper chromatography experiment
False
The baseline should be above the solvent
Why should you put a lid on a paper chromatography experiment?
To prevent the solvent from evaporating
What will happen to insoluble substances in paper chromatography?
They will not move up the paper
What kind of paper should you use for paper chromatography?
Cellulose filter paper
What is the pattern of spots called in paper chromatography?
A chromatogram
Are mobile and stationary phases periods of time?
No, they are substances
What is the mobile phase?
The molecules that can move up the paper
eg. liquids and gas
What is the stationary phase?
Molecules that can’t move
eg. paper
True or False:
The chemicals will move between mobile and stationary phases
True
What are the steps of the ink moving up the paper?
- Dissolving
- Moving a bit
- Binding to the paper
- Repeat
