What is a mixture?
A mixture is a combination of two or more substances that are not chemically combined.
Give examples of mixtures (e.g from home)
Sugar, salt and water mixture
Iron filling, salt and sugar mixture
Are mixture are impure substances
Mixtures are impure substances
How do we get pure substances from mixture?
The following are examples of getting pure substances:
- Magnetism decantation
To get pure common salt from a mixture of salt and soil/sand
Describe the produce as follows:
Water was added to the mixture of salt and until it dissolved. The water with salt was filtered from the sand using filtration paper. Then the water and salt mixture was boiling to evaporation.
The water evaporated and the soil remained at the bottom of container. The soil stayed on the filtration paper.
Common salt dissolves in water but soil is in soluble in water, when the mixture was added to water and stirred, the solution containing on the dissolved salt and remaining on the filter papers as the residue. The solute in the filtered crystallized when the solvent evaporated.
The solution of salt in water contained salt as a solute and water as a solvent.
This method is used to separate a mixture of 2 solids, one of which is soluble in a a solvent (e.g. water)
Diagram of a condenser
- To get pure water from salty water
- To get pure water from salty, the apparatus is set up as the diagram. The salty water is heated in the flask. The solvent vaporizes and condensers in the lie big condenser. The distillate is received in a beaker or test tube.
What does the liquid in the flask taste like?
It is salty
What does distillate taste like?
Supposing the liquid in flask is heated to dryness, what would be seen in the flask?
This method of getting pure water from salty water is called simply distillation. It can be used to get a pure solvent from its solution.
How does the lie big condenser work?
It cools a vapor until it turns into a liquid
Using simple English show what you understand by the terms;-
A combination of two or more substances that are not chemically combined
Is a uniform/homogeneous two substances mixture of a solute and a solvent?
Is a solid, gas, liquid that can be added into a solvent to form a solution, e.g. chalk? Is a substance (solid) that can mix in any solvent?
Is a liquid into which a solute is added dissolves to form solution e.g. water?
A liquid that contains small particles of a solid which are spread throughout a liquid and get settled on standing solids particles that don’t dissolve
Is what is got in container after filtration has been done the liquid obtained after filtration?
Is that result got after distillation done?
This is what remains in the server or filtrate paper after filtration
To separate a mixture of liquids that:
Mix uniformly e.g. water + ethanol when a homogenous mixture is formed, we say water and ethanol are miscible
The apparatus is set up as follows
Diagram of a condenser
The mixture of ethanol and water did not burn it was lit. But when the distillate was lit it burnt. The distillate burnt with a blue flame
Which of the two substances in a mixture burns with a blue flame?
Ethanol burns with a blue flame
Name the distillate.
How does a fractionating works.
When the mixture of water is heated, both the water and ethanol evaporate. In the column, water condenses and flows back into the flask. But the ethanol vapor continues rising into the lie big condenser, where it is condensed.
To make sure the column works properly, the temperature at point X trust be maintain at the boiling point of ethanol at about 78oc.
This method of separating liquid mixtures is called fractional distillation. It only works if the liquids have different boiling point. (Industrial)
Distillation of crude petroleum
Do not mix uniformly
They are heterogeneous mixture/immiscible mixtures
-When immiscible liquids are poured in to the separating funnel the form separate layers
-When the top is opened, the denser liquid pours off first. When it is drained off, the top is closed, and then the less dense liquid can be poured into separated beaker
How to separate a mixture of solids both of which are soluble in a common solvent
THIS VIDEO EXPLAINS MORE ABOUT MIXTURES