Structure of Matter
The state of matter is defined in terms of the phase transitions, which indicate the
change in structure and properties. Solids, liquids and gases are all made up
of microscopic particles. The behaviour of all these particles also varies in
three phases.
The Concept of Matter
Explain the concept of matter
Matter is anything that has mass and occupies space. In
other words, matter is anything that has weight and volume. For example, stone
is considered a matter because it has mass and it occupies space. Therefore,
everything we see around us is considered a matter.
The Particular Nature of Matter
Justify the particulate nature of
matter
Matter is made up of tiny particles. These particles are
either atoms or molecules. That is to say, atoms or molecules combine in
millions to form matter. Atoms or molecules are combined in chemical reactions
to form matter.
An atom is the smallest part of an element that can take part
in a chemical reaction. When two or more atoms combine, they form a molecule.
The nuclear attractive forces are responsible for holding
atoms together in a matter. Some matters have strong attractive nuclear forces
between atoms e. g gold, silver, and iron. Some matters have weak attractive forces
between atoms e. g water, oxygen gas.
The Kinetic Theory of Matter
Explain the kinetic theory of matter
The Kinetic Theory of matter describes the physical
properties of matter in terms of the behaviour of its component atoms or
molecules. It states that
“All matter is made up of
very small particles that are in constant motion”
This theory tells us about
two important things;
1. That matter is a combination of tiny (very
small) particles.
2. And all these tiny particles are always in
motion.
The motion of the particles in a matter was experimented
by a scientist known as Robert Brown in a Brownian motion experiment.
Brownian motion
This was an experiment conducted by a scientist, Robert
Brown, to investigate the motion of the tiny particles in a matter.
In his experiment, he put pollen grains in
water and observed them using a microscope. He observed that pollen grains
were moving in a random or irregular motion.
Mr. Brown discovered that the random motion of the
pollen grains in water was caused by the collisions between them and the
molecules of water. The pollen grains continued with the random motions since
the collisions did not stop. This motion is called Brownian motion.
Brownian motion is an
irregular motion of tiny particles suspended in a fluid.
Three States of Matter
Classify three states of matter
There are three states of
matter, namely:
1. Solid state
2. Liquid state
3. Gaseous state
Solid state is the state of matter, which includes
materials in which the intermolecular forces between molecules are greatest and the distance between molecules is small. Solids have a definite shape and volume.
Particles in a solid are closely packed together. Examples of solids are wood,
iron, glass, rubber, concrete, etc.
The liquid state includes substances in which the
intermolecular forces are low compared to the solid state, and there is a greater
distance between one molecule and another. Solid shave, no defined shape or
volume, but they take the shape of the container or vessel. Examples of
liquid substances are water, honey, spirit, kerosene, and petroleum.
The gaseous state is the state of matter in which there are no
intermolecular forces between molecules, hence, molecules are free to move from
one place to another. Gases have no defined shape or volume, but they fill the
whole container in which they are kept. Particles in gases are freest
compared to solids and liquids. Examples of gases are hydrogen, oxygen, and carbon
dioxide.
|
Solid state |
Liquid state |
Gaseous state. |
|
It is concerned with solid matter |
It
concerns liquid/fluid matter |
It is concerned with gases |
|
Have
high intermolecular |
Low
intermolecular force |
No
intermolecular force |
|
No
distance between molecules |
There
is little distance between molecules |
Molecules
are far from each other |
|
Good
examples are iron materials, wood etc. |
Good
examples are water, soda, kerosene and petrol |
Good examples are oxygen and hydrogen |
Elasticity
The Concept of Elasticity
Explain the concept of elasticity
Elasticity is the property of a body to return to its
original shape and size when the deforming force is removed. When force is applied
to a body, shape and size may change. If the force is removed from the
body, elasticity will cause that body to return to its original shape and size.
All objects that can retain their original shape and size
after the deforming force has been removed are known as elastic objects.
Examples of elastic objects are springs and rubber bands.
Materials which break when force is applied to them are
known as brittle materials. Brittle materials do not undergo
elasticity. An example of brittle materials is glass.
Materials which do not return to their original shape and size
after the deforming force is known as plastic materials. Plastic
materials undergo plastic deformation when extra force is applied. Examples of
plastic materials are plastic bags, plastic utensils and many more.
The Relationship between Tension and
Extension of a Loaded Elastic Material
Justify the relationship between
tension and extension of a loaded elastic material
The relationship between tension and extension of a
loaded elastic material is well explained in Hooke’s law. It states that
“Within the elastic limit, extension is directly
proportional to the force applied (tension)”
Tension can be described as the force(F) transmitted
within a string or rope, or wire when it is stretched or elongated. Extension
(e) is an excess length obtained after stretching a wire or rope, or string.
Hooke’s law states that when a force is
applied to an object, the length of the object will increase in the same
proportion as the force. If the limit of extension (elastic limit) is not
reached, the object can return to its original shape and size after the removal
of the applied force. However, if the elastic limit is reached, then the object
will not return to its original shape and size even after removing the applied
force.
Hooke’s law can be
expressed mathematically as,
Where ‘k’ is the constant known as the force constant or spring constant, and
its SI unit is Newton per metre (N/m).
The
relationship between tension and extension of a loaded elastic material can
also be explained using the following graph:
The above graph can be interpreted by describing
its parts as follows:
Part O –
A: Tension is directly proportional to extension. This was discovered by Hooke, and finally, he came up with a law called Hooke’s law. At this stage, the object
can return to its original shape and size if the tension is removed.
Point A:
This is known as the limit of proportionality or elastic limit.
Part A –
B: This region is called the region of elasticity. In this region, a small force
produces a large extension, which is not directly proportional to the extension.
Part B–C: This region is called the region of plastic deformation. In this region, material will not return to its original shape and size when the applied
force/tension/load is removed.
Beyond C:
Beyond this point, the object becomes thinner and ultimately breaks due to
excessive application of force.
The Application of Elasticity in Real Life
Identify the applications of elasticity in real life
In everyday life, we
often actually do the activities that are concerned with the application of
physics. Here are some of the applications of physics in everyday life, especially in the application of Elasticity:
Spring
mattress. When you sit or sleep on a spring mattress, futon style, push your
weight. Pressured by the compressed spring mattress. Due to the nature of its
elasticity, stretch a spring mattress again. Spring will be stretched and
compressed, and so on.
Springs
that is used as shock absorbers on motorcycles. Springs are used in the suspension
systems of motor vehicles. The purpose of this is to dampen the spring a surprise
when a motorcycle drives through an uneven road surface.
Another
simple example that you may often come across is the catapult. When it was
about to shoot birds with catapults, for example, rubber slingshots first
stretch (given the gravity). Due to the nature of its elasticity, long rubber
slingshots will return to normal after a tensile force is removed.
Adhesion and Cohesion
The Concept of Adhesion and Cohesion
Explain the concepts of adhesion and
cohesion
Matter is made up of molecules. That exerts a force of
attraction. This force of attraction may be either Cohesion or Adhesion.
Cohesion is the force of attraction between
the molecules of the same substance, for example, water molecules to water molecules.
Adhesion is the force of attraction between
the molecules of different substances example, water to glass molecules.
Water molecules can experience the force of cohesion among
themselves, while water molecules and glass molecules will experience the force
of adhesion.
Definite shapes of a solid
are due to the strong cohesive force among its molecules.
Shapes and meniscus of a liquid
When we carried out activities involving the determination of
volume in a liquid ring and a measuring cylinder. The description indicated that
the surface of the liquid was carved, forming a meniscus, and that the volume
must be read at the bottom or top of the meniscus, depending on the liquid
used. For mercury, the top of the meniscus is read.
The formation of a meniscus in a liquid is
due to forces of adhesion between the liquid and the walls of the container.
The adhesion of the liquid, such as water, to the wall of a vessel causes an
upward force on the liquid at the edge.
The opposite takes place in mercury; the meniscus of
water curves upwards, forming a concave shape. When a drop of each liquid,
mercury and water, is placed on a glass sheet, water spreads further than
mercury, because of mercury’s high cohesion force among its particles.
Why does water wet the glass?
Why does methanol not wet
the glass?
Applications of Adhesion and Cohesion in
Daily Life
Identify the applications of adhesion
and cohesion in daily life
The application includes the
following
1. To stick two different objects together.
Here we use the adhesive effects of tape or glue.
2. Adhesion can also be used to remove
harmful materials such as bacteria from drinking water. Adhesive forces are the
source of attraction between substances.
3. Cohesion assists in the transport of water in
plants and animals by allowing one molecule to pull others along with it.
4. The bodies of plants and animals also use
the cohesion of tissue to repair damage.
5. Ink sticks to paper because of the adhesive
force between the paper and ink.
Surface Tension
The Concept of Surface Tension
Explain the concept of surface tension
While you may not be able to walk on water, water stride
does. This is due to the property of liquid, which is known as surface tension.
Surface tension is the ability of the molecules on the
surface of a liquid to attract and stick to each other, allowing them to resist
an external force. Surface tension enables insects such as water striders and
mosquitoes to walk on water. It allows small objects, even metallic ones such as
needles and razor blades, to float on the surface of water.
Surface tension is a resultant attractive force between
molecules in a liquid. The molecules below the surface liquid have forces of
attraction between neighbouring particles. However, molecules at the surface
have no neighbouring molecules above them. This makes them have a stronger
attractive force than their nearest neighbours on the surface.
However, when some detergent is added to
water, the same objects sink to the bottom of the trough. This means that the
detergent interfered with the surface of the liquid so decreasing the tension
of the water surface.
Detergents are an example of surfactants. A surfactant is a
substance that reduces the surface tension of a liquid.
Note: the term surfactant
is an aerogun for surface-active agent.
Surface tension is affected
by the following
Nature of the liquid
Contamination/impurities
Temperature
Application of surface
tension:
1. In the extraction of impurities dating
laboratory process.
2. Surfactants are also used to make an emulsion
of a liquid like oil and water.
3. In the cleaning action of soap.
Applications of Surface Tension in Daily Life
Identify the applications of surface
tension in daily life
Application of surface
tension
1. In the extraction of impurities dating
laboratory process
2. Surfactants are also used to make an emulsion
of a liquid like oil and water.
3. In the cleaning action of soap
Capillarity
The Concept of Capillarity
Explain the concept of capillarity
This is the tendency of a liquid to rise in narrow tubes
or to be drawn into small openings such as those between the fibres of a towel.
Capillarity can pull a column of liquid upward until the weight of the liquid
becomes greater than the surface tension.
In a tube, capillarity depends on the tube’s diameter, but the weight of the water column depends on other factors besides it.
The smaller the radius of the tube, the higher the liquid
will rise in it. This implies that capillarity height is immensely proportional
to the diameter of the tube.
By definition
Capillarity is defined as the tendency of a liquid to rise
in narrow tubes or to be drawn into small openings such as those between the
fibres of a towel.
Capillarity
action is the ability of a liquid to rise or fall in a narrow tube.
Note:
1. Capillarity depends on the type of liquid.
For example if you dip capillarity tube in water the water rises in the tube
and above the level of the water in the vessel.
2. If the tube is dipped in mercury, the
liquid does not rise in the tube. It suffers capillarity depression.
Applications of Capillarity in Daily Life
Identify the applications of capillarity in daily life
The application includes:
1.
Capillarity is essential to plants and animals.
2. In
plants, it facilitates the transport of water and nutrients from the roots to
the leaves, where photosynthesis produces the plant's food. In animals, it assists
in the circulation of blood.
3.
Capillarity promotes the movement of groundwater.
4. It is the
principle on which paper and fabric towels work to absorb water.
5. Cotton
clothing in hot climates uses capillarity action to draw perspiration away from
the body.
6. In an
oil or kerosene lamp, capillarity draws the fuel up into the wick where it can
be burned.
7. A
writing that Rubin splits in the middle so that a fine capillary is formed.
Osmosis
The Concept of Osmosis
Explain the concept of osmosis
Defined as the movement of a solvent from a region of low
concentration through semi semi-permeable membrane.
Particles will diffuse through the membrane in an attempt
to equalise the concentration on either side. E.g. two solutions of different
concentration separated by a semi-permeable membrane. The membrane is permeable
to the smaller solvent molecules but not to the larger solute molecules.
Osmosis stops when the concentration becomes the same on either side of the
membrane.
Osmosis
stops when the concentration becomes the same on either side of the membrane.
.png)
Applications of Osmosis in Daily Life
Identify the
applications of osmosis in daily life
Applications of osmosis in
daily life:
1. Control the movement of water and
nutrients in and out of the cell.
2. Filtration processes.
3. Removal of harmful ingredients from
drinking water.
4. Removing salt from seawater to make
it suitable for drinking and for other domestic uses.
Post a Comment