Separation Techniques Flashcards
What is an element?
A pure substance made of only one type of atom
Elements are the simplest form of matter and cannot be broken down into simpler substances.
Define compounds.
Two or more different elements chemically bonded in a fixed composition
Compounds have unique properties that differ from the individual elements that compose them.
What are mixtures?
Two or more different substances physically bonded not in a fixed composition
Mixtures can be separated by physical means.
How can you separate an iron/sulfur mixture?
Use a magnet as iron is magnetic
This method exploits the magnetic property of iron.
What is the method to separate a sand/salt mixture?
Dissolve the mixture in water, filter to remove sand, and evaporate the water to get salt
This uses solubility and filtration techniques.
What is the process to separate a solid insoluble in a liquid?
Filter to obtain solid (filtration)
Filtration is effective for separating solids from liquids.
What is the method for separating a solid soluble in a liquid if the liquid is needed?
Simple distillation
Simple distillation involves heating the solution to vaporize the liquid and then condensing it back to liquid.
What are the steps in crystallization?
- Heat till point of crystallisation to evaporate water
- Leave to cool to form crystals
- Filter the solution to remove crystals as residue
- Dry between 2 filter papers
Crystallization allows for the formation of pure solid crystals from a solution.
How do you separate immiscible liquids?
Using a filtering funnel
Immiscible liquids do not mix and can be separated based on density.
What method is used for separating miscible liquids?
Fractional distillation to separate based on different boiling points
Fractional distillation is useful for separating mixtures of liquids with close boiling points.
What is the setup for chromatography?
- Place a small amount of the solvent into a beaker
- Draw a baseline using pencil on chromatography paper
- Place drops of dyes on the baseline and place the paper into the beaker
Chromatography is a technique for separating mixtures based on the movement of substances across a medium.
What does it mean if one mark is left from a dye in chromatography?
It indicates a pure substance
A single mark shows that the dye has not mixed with any other substances.
What does it indicate if a dye doesn’t move off the baseline?
The dye is insoluble in the solvent
This means the dye cannot dissolve in the solvent used.
What does more than one mark left from a dye suggest?
Each mark is a different substance in the mixture of the dye
Multiple marks indicate the presence of various components in the dye.
What is the formula for calculating the Rf value in chromatography?
Rf value = distance travelled by solute from baseline / distance moved by solvent from baseline
The Rf value helps in identifying substances based on their movement in the solvent.
