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The nature of matter - Coggle Diagram
The nature of matter
Separating and purifying substances.
A mixture of solid + solid
Use some difference in properties
For example, density, solubility, sublimation, magnetism
A mixture of solid in liquid
Filtration or centrifugation
Filteration
First you pour the mixture on the filter paper, so the filter paper will collect the solid substance which is called the residue and the liquid will go in the beaker and will be collected as a filtrate.
Centrifugation
Where the mixture is spun at high speed in a centrifuge. This causes the solid to be deposited at the bottom of the centrifuge tube. The liquids can be carefully decanted off.
A mixture of liquid + liquid ( immiscible )
Using a separating funnel of decantation
Decantation
The process is carried out by slightly tilting the immiscible mixture and slowly pouring out the top layer. After pouring out the top layer, the mixture can be tilted to complete the process.
Solution of solid in liquid
Crystallization
The impure substance is dissolved in water, then filtered, then it is heated gently to evaporate water to obtain a saturated solution, then it is cooled slowly and the pure crystals forms leaving the impurities in the solution.
To obtain liquid use distillation
The boiling point of the liquid is usually very much lower than that of the dissolved solid. The liquid is more volatile than the dissolved solid and can easily be evaporated off in a distillation flask. It is condensed by passing it down a water - cooled condenser and then collected as the distillate.
two (or more) liquids mixed together (miscible)
Fractional distillation
The most volatile liquid in the mixture distils over first and the least volatile liquid boils over last. For example, ethanol boils at 78 degrees Celsius whereas water boils at 100 degrees Celsius When a mixture of the two is heated, ethanol and water vapors enter the fractionating column. Glass beads in the column provide a large surface area for condensation. As the vapors rise up the column. Ethanol passes through the condenser first as the temperature of the column is raised above its boiling point. Water condenses in the column and flows back into the flask because the temperature of the column is below its boiling point of 100 degrees Celsius. The temperature on the thermometer stays at 78 degrees Celsius until all the ethanol has distilled over. Only then does the temperature on the thermometer rise to 100 degrees Celsius and water distil over. Finally the two liquids can be separated easily.
Solution of two (or more) solids in a liquid
Chromatography
First put a dot of ink this is marked as " A " on the chromatography paper and then put the paper in ethanol
The solvent begins to move up through capillary action
The solvent moves up the paper, taking different components along at different rates
Rf value
Distance moved by the substance divided by distance moved by the solvent front.
States of matter
Matter
Anything that has mass and takes up space.
Three states
Liquid
Density is moderate to high
No definite shape - takes the shape of the container
Has a fixed volume
Generally flows easily
Gas
Low density
No definite shape - takes the shape of the container
No fixed volume - expands to fill the container
Flows easily
Solid
High density
Has a definite shape
Has a fixed volume
Does not flow
Changing temperature and pressure can change the state of substance.
Sublimation
Few solids do not melt when heated it directly changes to gas.
Dry ice
Evaporation, boiling and condensation
Boiling
If the liquid becomes hot enough, bubbles start to appear. This is boiling
Boiling point
Water boils easily
But ethanol is quite a volatile liquid.
Condensation
Reverse of evaporation
This is usually brought about by cooling.
Evaporation
If a liquid is left exposes to the air, it evaporates
Larger the surface area faster the evaporation.
Warmer the liquid faster the evaporation.
Melting and freezing
Melting
When a pure substance turns into liquid it is called its melting pointing
Freezing
When the process is reversed at precisely the same temperature if a liquid is cooled down it is called its freezing point.
Pure substances
Consists of only one substance
Definite boiling and melting point
No impurities
Effect of impurities
Lowers the melting point
Raises the melting point
Types of mixtures
Mixture is at least made up of two substance.
Solution
The states are completely mixed to become one single state or phase.
Example
Salt water
Solute
The solid that dissolves in the solvent.
Salt is a solute
Solvent
In which the solute mixes
Water is a solvent
Atoms and molecules
Pure substances
Compounds
Elements
Substances that cannot be chemically broken down into simpler substances.