FORM ONE-STRUCTURE AND PROPERTIES OF MATTER - MTAHINI [EDUCATION MAKTABA]

Monday, 30 December 2019

FORM ONE-STRUCTURE AND PROPERTIES OF MATTER

1.0         STRUCTURE AND PROPERTIES OF MATTER

1.1            Structure of matter
Matter –is the anything that has mass and occupies space.
An atoms –is the basic particle of matter that can take place in a chemical reaction.
A molecules –is a chemical combination of two or more atoms.

Ø  Three states of matter
                                  i.            Solid
                                ii.            Liquid
                              iii.            Gas

                                  i.            Solid
Characteristics of solid
1)      Have a definite shape and volume
2)      Particles are closely packed together(they are held together)
3)      Particles are vibrate in fixed positions
4)      Are not free to move
5)      Have strong inter-particle forces(inter-particle distance is almost negligible)

Note: Ice is the solid state of water. Examples of solids are wood, stones and books

                                ii.            Liquid
Characteristics of liquid
1)      Have fixed volumes but variable shapes (assume the shapes of container.
2)      The atoms and molecules are only slightly farther apart.
3)      The inter-particle forces are slightly weaker than in solid.
4)      Are freedom to move
5)      The particles move faster as slide past each other.

Examples of liquids are water, kerosene and milk.
                              iii.            Gases
Characteristics of gases
1)      Have neither a definite shape nor size (always fill the containers in which they are held, it expand to fill the container)
2)      The atoms and molecules are moving so faster
3)      Are so far apart that do not interact each other at all
4)      Have weakest inter-particle forces of attraction
5)      The particles move randomly due to weak bonding

The particular nature of matter
Qn. State Brownian motion
        Brownian motion states that” matter is made up of tiny particles that are in a state of
        continuous random motion”.
Qn. State Kinetic theory of matter
        Kinetic theory of matter states that” it state that all matter is made up of very small
        particles that are in constant motion”.
        
        Note: The temperature of a substance has an effect on the movement of its constituent
        particles.
Ø  An increase in temperature causes an increase in movement which is as a results of increase in energy.

6.2 Elasticity
Elasticity –is the ability of a deformed body to return to its original shape and size when deformation force removed.

Relationship between tension and extension of a loaded elastic material
Elastic limit –is the maximum point of deformation that a body can undergo and return to its original shape when deformation force is removed.

Plastic deformation –is the process by which elastic materials are deformed such that they loose their elasticity Or –is the process by which materials it will not regain to its original shape even though it does not break.
 Note: Materials that undergo plastic deformation are called inelastic or plastic materials.

The graph of tension against extension


Hooke’s law
        State that” within elastic limit, the extension of a spring is directly proportional to the force applied (tension), provided the elastic limit is not exceeded”.
 Then
                 The SI-unit of k is N/m
               
                   Where
                              K –elastic force constant
                              X –distance stretched (extension)
                              F –applied force (tension)

Application of elasticity in real life
        i.            In home are  used in spring in furniture
      ii.            In home applied in clothing
    iii.            In home applied in rubber bands that hold things together
     iv.            In industry for measuring weight
       v.            In industry for conveyor belts
     vi.            In industry for steel beams used in construction
   vii.            In transport for support cables for bridges
 viii.            In transport for aeroplane wings

6.3 Adhesion and cohesion
Adhesive force is the force of attraction between the molecules of different substance.
Cohesive force is the force of attraction between the molecules of same substance.

Qn. Explain the formation of meniscus of liquid due to force of adhesive between the liquid and the walls of container.


1.      Meniscus in water
The meniscus of water curves upwards forming a concave shapes.

2.      Meniscus in mercury
The meniscus of mercury curves downwards forming convex shapes.

Applications of adhesion and cohesion forces.
a)      In stick two different objects together, use adhesive effects of tape or glue
b)      Adhesive ,used to remove harmful materials like bacteria from drinking water
c)      Cohesion, used in transport of water in plants and animals
d)      The body plants and animals use cohesion of tissue to repair damage.
e)      Ink stick on paper because adhesive forces between ink and paper are greater than the cohesive forces in the molecules of ink.

6.4   Surface tension
Surface tension is the ability of the surface of liquid to behave like a fully stretched elastic skin.

Note: Surface tension is the result of attraction forces between the molecules of liquid, cohesive forces is responsible for surface tension of a liquid.
  Examples of surface tension are water striders, mosquitoes, razor blades, chalk powders, paper clips e.t.c

Qn. How to reduce surface tension of the liquids?
Ø  Surface tension of liquid decrease when detergent introduced to the liquid. Example of detergents is surfactants.
Surfactant is an acronym for “surface active agent”

Factors affecting surface tension of liquid
1.      Nature of liquid. –different liquids have different surface tension. Example mercury has higher surface tension than water.
2.      Contamination. –impurity in a liquid lower surface tension
3.      Temperature. – surface tension of liquid decrease as increase temperature

Application of surface tension
                                i.            The cleaning action of soap. –when the soap remove dirty to clothes
                              ii.            Mosquitoes normally lay their eggs on water. –oil reduce surface tension
                            iii.            Hot soup has a lower surface tension than cold soup. Hot soup spread over large area of a tongue.
                             iv.            In extraction of impurities during laboratory processes

6.5 Capillarity
Capillarity –is the ability of a liquid to rise or fall in a narrow tube.
 Application of capillarity
1.      Capillarity is essential to plants and animals
2.      Capillarity promotes the movement of ground water.
3.      In an oil or kerosene lamp capillarity draws the fuel up into weak to be burnt
4.      Principle in which paper and fabric towels works to absorb water.

Diffusion
Diffusion –is the movement of particles from a region of high concentration to one of low concentration

Application of diffusion
1.      Balancing the concentration of water and nutrients in and out of the cells of living organisms
2.      Detecting harmful substances in the environment
3.      In the use of air fresheners and other sprays
4.      In the process of respiration  oxygen from the lungs diffuses into the bloodstream


6.6   Osmosis
Osmosis –is the movement of a solvent from a region of low concentration to one of high concentration through semi-permeable membrane

Application of osmosis
1.      Controlling movement of water and nutrients in and out of the cells
2.      Filtration processes
3.      Removal of ingredients from drinking water
4.      Removing salt from seawater, so as to make it suitable for drinking and for farther domestic uses

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