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Methods of Separation
The different ways to separate mixtures.
23
Chemistry
7th Grade
04/11/2011

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Cards

Term
What method is used separate a mixture of two liquids and what characteristic property is involved?
Definition

1. Fractional Distillation

2. Boiling Point

Term
What method is used to separate two soluble solids and what characteristic property is involved?
Definition

1. Fractional Crystallation

2. Solubility at different temperatures

Term
What method is used to dissolve two insoluble solids and what characteristic property is involved?
Definition

1. Separation by Floatation

2. Density

Term
What method is used to separate one soluble and one insoluble solid and what characteristic property is involved?
Definition

1. Separation by Filtration

2. Solubility in a liquid

 

Term
Pure Substance
Definition
Compound or element. A substance that cannot be separated any further. Characteristic properties will remain each time tested.
Term
Mixture
Definition
Two or more pure substances combined. Combination of elements and/or compounds not chemically combined (ex. air, saltwater)
Term
Can mixtures be restored after separation?
Definition
Some can be restored by simply, but others cannot be restored by just mixing. Also, other cannot be restored in anny way.
Term
Fractional Distillation
Definition

1. Heat mixture and record temperature every 30 seconds

2. Plateus in temperature are boiling points and for each boiling point there is a liquid in the mixture this will determine how many fractions will need to be taken

3. Re-heat the mixture and collect the fractions

Term
Fractional Crystalliztion
Definition

1. Dissolve solids in water heat mixture boiling away water until precipitate appears

2. Filter through hot filter system

3. Cool the filtrate and crystals sould appear

The residue is the solid with a lower solubility at high temperatures and the filtrate is the solid with a higher solubility at high temperatures.   

Term
Separation by Filtration
Definition

1. Place mixture in water and shake.

2. Filter through filter system

3. Boil away water from filtrate

The residue is the insoluble solid and the filtrate with the water boiled away is the soluble solid. 

Term
Separation by Floatation
Definition

1. Place the mixture in water and shake

2. Skim the surface of the water to separate one solid

3. Boil away water from the other to separate the second solid

The solid that floated and was skimmed off the surface of the water is the solid with the less density. The solid at that was at the bottom of the container is the solid with a greater density.

Term
How to separate a mixture where substances are dissolved on minute quantities (ink) and what property is involved?
Definition

1. Chromotography

2. Molecule Size

Term
How to separate a mixture of gases and what property is involved?
Definition

1. Liquefy gases and fractionally distill

2. Boiling Point

Term
Describe how chromotography works
Definition
When a solvent moves through capilary action, it 'drags' whatever is dissolved in it along with it. The further it moves by capilary action, the slower it goes. So, just as a stream first drops boulders then rocks and finally sand and silt as it slows down, the larger molecules (red) fall out first then the smaller (yellow and green) and finally, the smallest (blue).

Term

[image]

 

Based on this graph how many substances are in this mixture? Which fections contian pure substances? Which fraction has the highest density? (e doesn't exist)

Definition

1. 2

2. b & d

3. d

Term
What is Petroleum? And how is it separated?
Definition
Also called "crude oil" petroleum is vegetable and animal material decaying over millions of years. The components of petroleum have different boiling points, so they can be fractionally distilled.
Term
What is Skimming used for?
Definition
Used to separate insoluble solid from liquid if solid is less dense.
Term
What is decanting used for?
Definition
Used to separate insoluble solid from liquid if solid is more dense.
Term
Residue
Definition
Insoluble Solid
Term
Filtrate
Definition
Soluble Solid
Term
Steps of fractional crystallization
Definition

1. Place solid mixture in 2.5X the amount of water

2. Heat until 1/2 the water is gone and precipitate appears

3. Filter at 70C or higher (hot filter)

4. Dry solids and do quantitative tests 

Term
How much of air is nitrogen and what is its boiling point? How much of air is oxygen and what is its boiling point?
Definition

1. 80% 196C

2. 20% 183C

One air is liquified it can be fractionally distilled into separate gases.

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