1º the molecule 2º physical properties 3º states of water 4º the universal solvent
DESCRIPTION
WATER. 1º THE MOLECULE 2º PHYSICAL PROPERTIES 3º STATES OF WATER 4º THE UNIVERSAL SOLVENT 5º SEPARATION TECHNIQUES. O. H. H. 1. MOLECULE OF WATER. A molecule of water has one atom of Oxygen and two atoms of Hydrogen. 1. MOLECULE OF WATER. The chemical formula of water is. H 2 O. - PowerPoint PPT PresentationTRANSCRIPT
1º THE MOLECULE
2º PHYSICAL PROPERTIES
3º STATES OF WATER
4º THE UNIVERSAL SOLVENT
5º SEPARATION TECHNIQUES
WATER
1. MOLECULE OF WATER
OHH
A molecule of water has one atom of Oxygen and two atoms of Hydrogen.
H2O
The chemical formula of water is
1. MOLECULE OF WATER
One molecule of water has got a very small mass of 0.000 000 000 000 000 000 000 03 g.
That’s a very small number. Isn't it?
3 10-23 g
1. MOLECULE OF WATER
When we drink a glass of water (240g), we are drinking 8,000,000,000,000,000,000,000,000 molecules of water.
That's a very big number. Isn't it?
1. MOLECULE OF WATER
2. PHYSICAL PROPERTIES
The density of liquid water is 1 gram per cubic centimetre.
d = 1 g
cm3
1 g
1 cm
1 cm
1 cm
2. PHYSICAL PROPERTIES
The density of liquid water is higher than the density of ice (frozen water).
The ice floats above the water
2. PHYSICAL PROPERTIES
The fusion point of water is 0 ºC (zero degrees Celsius).
Ice and liquid water can be together at 0 ºC.
2. PHYSICAL PROPERTIES
The boiling point of water is 100 ºC (one hundred degrees Celsius).
Liquid water and water vapor can be together at 100 ºC.
3. STATES OF WATER
Solid
1. Molecules are strongly united
2. Molecules are perfectly ordered
3. Molecules can’t move
4. All molecules form a crystal structure
Why do you think a solid has got a fixed form?
Why do you think it’s very difficult to compress a solid?
3. STATES OF WATER
Liquid
1. Molecules are strongly united
2. Molecules are disordered
3. Molecules form small groups
4. These groups can move among themselves
Why do you think a liquid hasn’t got a definite form?
Why do you think it’s very difficult to compress a liquid?
3. STATES OF WATER
Gaseous
1. Molecules aren’t united
2. There isn’t any force between them
3. Molecules are totally disordered
4. Molecules can move freely in all directions
Why do you think a gas hasn’t got a definite form?
Why do you think it’s very easy to compress a gas?
3. STATES OF WATER
VaporisationFusion
Solidification
Sublimation
Sublimation
Condensation
SOLID LIQUID GASEOSOUS
0 ºC 100 ºCTEMPERATURE
Changes of states
4. THE UNIVERSAL SOLVENT
Water is the universal solvent. In nature we can find water in the seas, rivers, subterranean… and water always contains many other substances.Living beings, drinks, foods, and chemical products are formed by water.
4. THE UNIVERSAL SOLVENT
A solution is a homogeneous mixture. The most abundant part is called the solvent, and the less abundant part is called the solute.
Salt Water Salted water
+ =
Solute + Solvent = Solution
4. THE UNIVERSAL SOLVENT
The molecules of water capture the ions of the salt. Later, all the molecules of salt are mixed among the molecules of water. The crystal structure of salt is destroyed.
++
++
++
++
Salt before being mixed
+
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+
+
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+
How a salt is dissolved in water
Salt after being mixed
5. SEPARATION TECHNIQUESFiltration
Beaker
Funnel
Filter
We use this technique to separate dissolved particles in water
We put a paper filter in a funnel
If particles have a size bigger than the porous of the paper filter, they won’t be able to pass through them
Clean water can pass and fall down into a beaker
5. SEPARATION TECHNIQUES
Decantation
Oil
Water
Separating funnel
tap
stopper
We use this technique to separate two immiscible liquids.
Oil, less dense, is above water
Opening the tap, water is falling down, drip-drop
When oil is going to escape we turn off the tap
5. SEPARATION TECHNIQUES
Crystallization
Crystallizer
Aqueous solution
Salt
Evaporation
The solution is heated by the sun
Water is evaporated
Finally, we can see crystallized salt in the crystallizer
Distillation
5. SEPARATION TECHNIQUES
Clamp stand
Bunsen burner
Ethyl alcohol and water
Steam
Clamp Thermometer
Distillation flask
Condenser
Cooling water
Condensed alcohol
Cold water
Receiving flask
Distilled alcohol
We use this technique to separate mixed liquids
We heat the mixture in a distillation flask
At 78 ºC ethyl alcohol is boiling and it escapes from the flask
Alcohol is condensed into the refrigerator tube
Finally we have distilled alcohol in an Erlenmeyer flask