7E - Separation techniques Flashcards
What is a suspension?
A type of mixture where the solids settle out over time.
What is a colloid?
A type of mixture where the solid pieces are smaller so they don’t settle out. The mixture looks cloudy or opaque.
What is a solution?
A type of mixture where the solids break up intosuch small pieces that the mixture is transparent.
What is a solute?
A solid in a solution.
What is a solvent?
The liquid in which the solute(the solid) dissolves.
Can gases dissolve?
Yes. Some can dissolve in water like oxygen and carbon dioxide.
When an insoluble solid is added to water, what type of mixture is formed?
A suspension or a colloid.
Total mass of solution =
mass of solvent + mass of solute
Can other liquids apart from water be used as solvents?
Yes. For example, alcohol.
A solute can’t dissolve in water. Does this mean it can’t dissolve in other sovents?
Not necessarily.
What does it mean if a solution is saturated with a solute?
No more solute can dissolve with the same temperature and amount of solvent.
(if you want more to dissolve, you can increase the temperature or the amount of solvent).
What is the solubility of a substance?
The amount of a solute that will dissolve in a fixed amount of solvent at a particular temperature.
What separation method is being shown?
Filtration.
What can filtration separate?
Solids from a suspension (large pieces that haven’t dissolved).
i.e. sand from a mixture of sand and water.
What separation method is being shown?
Evaporation
What mixtures can evaporation separate?
Solids from a solution or colloid.
(i.e. a salt from a salt solution)
What separation method is being shown?
Distillation
What mixtures can distillation separate?
A liquid from any type of mixture.
(i.e. Pure water from a salt solution)
What separation method is being shown?
Chromatography
What mixtures can chromatography separate?
individual solutes from a mixture of solutes.
(i.e. colours found in ink).
How can we interpret a chromatogram?
Each substance travels a unique distance so it can be used to identify subtances in a mixture.
What is evaporation?
When a liquid turns into a gas at its surface.
Happens at any temperature (gets faster as temperature increases).
What is boiling?
When all the liquid is trying to turn into a gas at the same time.
Happens at boiling temperature. (100ºC for water)
Gas is formed from the liquid below so bubbles rise.
What are the differences between evaporation and boiling?
In evaporation, the only the liquid at the surface turns into a gas while in boiling the whole liquid turns into a gas.
Evaporation happens at any temperature while boiling only at boiling point.
Describe the flame
Quiet yellow flame
Describe the flame
Medium blue flame
Describe the flame
Noisy blue flame
For what is this flame used?
Safety flame: used when not heating.
For what is this flame used?
Used for gentle heating.
For what is this flame used?
Used for rapid heating.
