Matter - Form 1 = Physics

 Why do molecules at the surface of liquid have higher energy as compared to molecules in bulk?

When some liquid evaporates, the average speed of the molecules remaining will     Answer  

Substance is made up element and compound.

Element is the substance with limit of chemical analysis.

Chemical Analysis, the study of the chemical composition and structure of substances. 

Compound is made up of two or more element.

Matter is made up of atoms, ions and molecules.

     Matter increase in volume(expand) when temperature increase    

      Decrease in volume(contraction) when temperature decrease    

Gas is easily compressible.

Liquid is slightly compressible

Solid is incompressible . Do not affected by the change of pressure.

Kinetic Theory of Matter

states that all matter is made of small particles that are in random motion and that have space between them.

The kinetic molecular theory of matter states

Matter is made up of particles that are constantly moving. All particles have energy, but the energy varies depending on the temperature the sample of matter is in. This in turn determines whether the substance exists in the solid, liquid, or gaseous state.

    Melting                        

 When solids are heated, their constituent particles (atoms, molecules or ions) get energy and vibrate more violently. Vibrations of these particles overcome (exceed) their binding forces. The particles become mobile. The crystalline structure of solid is destroyed. A liquid state is reached and the particles are free to move. The temperature at which this happens is called Melting Point

Melting point tell the strength of the force holding the particles.

Substances with high melting points have strong forces between their particles. Those with low melting points have weak forces between their particles.

    Freezing     

Is opposite of Melting.

The process is reversed at the same temperature if a liquid is cooled.

The melting point and freezing point of any given substance are both the same.

Melting is not affected by any changes in atmospheric pressure.

   Boiling  

liquid to vapour happen at particular temperature.

   Evaporating   

liquid to vapour happen at any temperature.

- takes place at the surface of liquid

The large surface area the faster liquid evaporates

The warmer the liquid is, the faster it evaporates. Thus, surface area and temperature affects the rate of evaporation of a liquid.

   When a liquid is heated, its molecules get more energy and move faster   .  

As the heating goes on, its molecules vibrate even faster. Bubbles of gas (due to air dissolved in water)

   Boiling Point  

The molecules at the surface of the liquid gain enough energy to overcome the forces holding them together. They break away from the liquid and from a gas (vapour).

    The temperature at which a liquid boils explains how strong the forces holding its particles (molecules) together are.   

The boiling point of a liquid can change if the surrounding pressure changes. I

If the surrounding pressure falls, the boiling point also falls. The boiling point of water at standard pressure (760 mmHg) is 100°C.

On a high mountain, where pressure is low, it is lower than 100°C.

  Condensation   

when gas cooled down its particles lose energy

they move more and more slowly . 

When they knock each other , does not have enough energy to bounce away.

they stay together and liquid form that is Condensation - change from gas(vapour) to liquid

When the liquid is cooled further, the movement of the particles slows down even more. Eventually, they stop moving and a solid forms. This is Solidification(Freezing) - change from liquid to solid 

   Sublimation   

few solid dont melt when they are heated.

they change from solid to gaseous without undergo  liquid state.

Sublime is directly change from solid to gaseous Example of solid sublime is Iodine, solid Carbondioxide and Ammonium Chloride

Sublimation occur at particular temperature according to the solid.

THE IMPORTANCE OF CHANGING FROM ONE STATE OF MATTER TO ANOTHER

    Separation Of Mixture   

Mixture can be separated by distillation , evaporation 

Distillation can be used to separate the mixture of two or more substance of different boiling point eg Water and Alcohol

    Industrial Manufacture of Product    

Example of process used is distillation

     Refining petroleum or crude oil       

     Drying crops and clothes     

   Ice formation in Refrigator   

   Melting metal to make alloy   

   Test Purity  Of Substance   

Presence of impurity may lower or raise the boiling point.

Pure substance melt and boil at definite temperature

Boiling point and melting point is used to measure purity of substance (sample).

eg: the boiling point of sea water is higher than and melting point is lower than pure water

     Formation Of Rain    

   The particles of matter are held together by the strong electrostatic force    

   Solid state   

Solid made up of small particles tha are closer together

No free movement  of particles . 

They can not move around freely , instead vibrate about fixed position.

Make solid to have fixed shape.

   Liquid State  

force of attraction is weaker than solid.

Liquids particles  have more kinetic energy than solids. and can move along each other .

The binding forces are strong when particles come close to one another.

 It is thought that the particles of a liquid are fairly randomly arranged but consist of "clusters" closely packed together. This property makes a liquid to have a definite volume.

 However, since the particles are fairly free to move a liquid does not have any characteristic shape 

liquid will always take the shape of its container.

Liquids have more kinetic energy than solids. If you add heat energy to a liquid, the particles will move faster around each other as their kinetic energy increases. Some of these particles will have enough kinetic energy to break their liquid bonds and escape as a gas (evaporation).

                                               Gaseous State  

 Particles moves independently.

Particles are far apart.

Its particles have more energy than solid and liquid

Particles move rapidly and randomly - in container when move collide with each.

Solid  to Gas   -   Sublimation

Gas to Solid    -   Deposition

Liquid to Gas -  boiling (vapourization)

Gas to Liquid  -  condensation

Liquid to Solid -  freezing

Gas to Liquid  -  melting

  Physical Change  

only physical change but nature not changed

Characteristics of Physical Change

• No new substance formed
• no change of weight
• Changed Back
• need little heat to be change

Note : Change Physical Properties

  Chemical Change  

refers to a change which is permanent in nature

eg : wood to ash

Characteristics of Physical Change

• new substance formed
• change of weight
• not Changed Back
• need more heat to be change

Note : Change Chemical Properties

 

 Napthalene is the ingradient found in mothballs

https://www.youtube.com/watch?v=MostFAuz02o

 Suspension is a heterogeneous mixture of a finely distributed solid in a liquid. 

Eg; Muddy water.

EMULSION

Is opaque mixture of  tiny droplets of one liquid suspended in another liquid.

Miscible liquids are ones that can mix together – like water and ethanol. 

Immiscible liquids are ones that can't – like oil and water. 

Fractional distillation separates miscible liquids that have different boiling points.

   Fraction distillation used when liquid have Boling point which are differ for few degrees,, no other ways     

Example ethanol boil at 78 °C while water is 100 °C

Solvent Extraction or Separation (Liquid -  Liquid  Extraction)

is the method of remove soluble material by using selective solvent Eg water

How : material will be more soluble in one solvent than other solvent

Organic Solvent - Diethyl ether alternative vegetable oil, petrolium product and vitamins

Solution - with Water

To remove the impurities which are water soluble

Funnel huwekwa kizibo na kutingishwa kisha maji na chemical hujitenga.

Kunatokea layer mbili ya juu na chini.

Fungulia funnel, maji yatatoka kwanza kisha Diethyl Ether

Denser Liquid Layer , itatoka ya kwanza , kisha less denser ambayo ni Diethyl Ether

Confugaration