INTRODUCTION TO CHEMISTRY

Definition: Chemistry is a branch of science which deals with the composition, properties and structure of
matter and the changes matter undergo.
Science is the scientific study of nature.
MATTER: – Is anything that has mass (weight) and occupies space
Matter includes materials or substances of nature which make up our environment such as water, air, stones, plants,
animals etc
There are three branches of science which are Physics, Chemistry and Biology
BRANCHES OF CHEMISTRY
Branches of chemistry include (i) Physical chemistry (ii) Organic chemistry (iii) Inorganic chemistry
(iv) Analytical chemistry (v) Biochemistry (vi) Chemical engineering.
Physical chemistry deals with the relations between the physical properties of a substances and their chemical
composition and transformations.
Organic chemistry deals with the properties and behavoiur of organic compounds.
Inorganic chemistry deals with properties and behavior of inorganic compounds.
Analytical chemistry deals with the studies of instruments and methods used to separate, identify and quantify chemical
species in matter.
Biochemistry deals with the study of chemical processes that occurs in living things.
Chemical engineering deals with the design, development and operation of processes that convert raw materials into
useful products.
The people who study chemistry are called CHEMISTS.
The people who studied chemistry in Ancient time were called ALCHEMISTS
Since chemistry is a science that involves experiments and practical work, chemists have to acquire scientific skills in
order to be successful in obtaining facts and verifying them. successfully. These skills include:
(i) Making thorough observations.
(ii) Recording accurately what has been observed
(iii) Organizing the observed and recorded information.
(iv) Repeating tests to ensure observations are accurate.
(v) Drawing conclusions from observations
(vi) Predicting possible outcomes of similar experiments
Therefore, chemistry students should apply these skills to be able to think logically and critically.
RELATIONSHIP OF CHEMISTRY WITH OTHER RELATED DISCIPLINES
Chemistry is related with other disciplines such as physics, biology, agriculture, geology, environmental
sciences and mathematics.
WHY STUDYING RELATIONSHIP BETWEEN CHEMISTRY AND OTHER DISCIPLINES
IMPORTANT?
(i) It helps to understand the world around us and give insight to physical and biological
processes.
(ii) It provides useful integrated skills and acts as a foundation for understanding scientific skills
through researching different phenomena
(iv) It helps to understand different professions resulting from learning chemistry, eg a person
who studies chemistry with other discipline may become a medical doctor, pharmacist,
nurse, chemical analyst, laboratory technician, researcher, chemical engineer, teacher and
environmentalist. Therefore, a chemistry may be employed in hospitals, schools, research
centres, energy sectors, chemical industries, etc.
The following are some disciplines which are related to chemistry
BIOLOGY: Chemistry and Biology are related in biochemistry and biotechnology.
Biochemistry studies the chemical processes that occurs within living organisms for understanding biological
systems.
Biotechnology involves the use of living organisms to produce economically useful products by combining
the knowledge and skills from chemistry, biology and chemical engineering
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Generally, the relationship between chemistry and biology bring development that solves daily life
challenges related to agriculture, medicine, nutrition and environmental issues.
PHYSICS: Chemistry and physics are related in physical chemistry.
Physical chemistry drives innovations and technological advancements in various areas such as medical
instruments, materials science and products from manufacturing industries.
AGRICULTURE: Chemistry and agriculture are related through agro-chemistry.
Agro-chemistry deals with the chemical processes related to plants, animals and soil health, crop protection
and fertilizers. It ensures food availability and security as well as good agricultural practices which improves
the quality of agricultural products.
GEOLOGY: Chemistry and geology are related through geochemistry field.
Geochemistry field applies chemistry theores and principles in investigating the chemical composition and
processes of the earth and other planets. Geochemists use their knowledge in investigating the abundance
and distribution of chemical elements in rocks and minerals which is the foundation of mining industry.
ENVIRONMETAL SCIENCE: Chemistry and environmental science are related in environmetal
chemistry and atmospheric chemistry.
Both fields apply chemistry theories and principles to study the ineractions of chemicals in the environment
such as pollution and their impacts to the natural world.
MATHEMATICS: Mathematics is applied in almost all areas of chemistry including physical chemistry,
analytical chemistry, inorganic chemistry, organic chemistry and biochemistry. It is applied in measuring of
volume, temperature and concentration of chemical substances, calculating percentage and ratios that
expresses concentration, composition and products of chemical reactions. It allows a chemist to conduct
precise experiments, make predictions and develop deep understanding on the principles governing the
behavior of matter.

APPLICATION (IMPORTANCE/ CONTRIBUTION) OF CHEMISTRY IN THE DEVELOPMENT

OF A MODERN SOCIETY
Chemistry plays a significant role in the development of a modern society. It has influenced most aspects of
life including healthcare, energy production and environmental sustainability. Due to practical application of
chemistry the quality of life for many people worldwide has improved. Most of the products that are
obtained by the application of chemistry are useful for development of modern societies.
These products are processed in different areas such as agriculture, medicine, nutrition and cooking,
manufacturing industries etc.
AGRICULTURE
Agriculture is a practice of growing crops and keeping animals. Farmers use many products made through chemistry
knowledge to get better agriculture yields. These products include fertilizers, animal vaccines, pesticides, weed killers
and processed animal feeds.
Fertilizers are used to improve the quality and quantity of crops.
Pesticides are used for destroying insects or other organisms harmful to plants. Pesticides are also used in animal dips to
kill pests such as ticks that attack animals
Animal vaccines are used to protect animals from diseases and also to prevent transmission of diseases between
domestic animals and human being.
MEDICINES
Medicines found in medical stores and pharmacies such as Panadol, coughing syrups, vaccines and food supplements
are all made by application of chemistry. These materials ensure our well being through the treatment and prevention of
diseases.
NUTRITION AND COOKING
Chemistry has an impact on the tastes, texture and nutritional value of food. Chemistry helps in understanding of
different food components such as carbohydrates, proteins, fats and oils, vitamins and minerals. Chemical reactions
involved in cooking help to have food that are healthy and palatable. For example, chemical processes are useful in the
preparation of breads, cakes, rock buns and biscuits.

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 MANUFACTURING INDUSTRIES
Textile industries, chemical industries, paper industries, food and beverage industries, transport industries,
communication industries, plastics manufacturing industries, construction materials industries all depends on chemical
processes. Most of the machine parts are made of metals, plastics and rubber which are made through chemical
processes. Products such as cements, rubber, papers, chemicals are made through chemical processes in these
industries.
FOOD AND BEVERAGE INDUSTRIES
Chemistry knowledge is used in preservation of foods especially canned and bottled food. Chemicals commonly used as
food preservatives are common salt, nitrates, nitrites, citric acid and alcohol such as ethanol.,
Chemistry knowledge is also used in preparation of baked foods such as breads, cakes, biscuits etc.

TRANSOPTAION
Fuels and lubricants used in motor vehicles, aircrafts, motorcycles, ships are all produced by chemical processes. Other
materials made by application of chemistry found in the means of transport include seat covers, paints, coolants,
carpets, batteries and tyres,
COMMUNICATION AND TECHNOLOGY
Chemistry plays a role communication and technology since it is applied in the development of batterie and
electronic devices and transmission of data through various networks
Radios, televisions, telephones, computers, papers are example of materials used in communication made through
chemical processes.
HOME CARE PRODUCTS AND COSMETICS
Soaps, detergents. Paints, Disinfectants, Air fresheners and polish are examples of home care products made through
chemical processes which are used to make home and the surrounding clean and more comfortable to live in.
Cosmetics which are used to improve one’s appearance or odour are all made through chemical processes. These
include deodorants, creams, lotions, perfumes, lipsticks etc.

CHEMISTRY FOR PROFESSIONAL (CAREER) DEVELOPMENT

Through studying chemistry, we get professions like Doctors, teachers, nurses, pharmacists, geologists, chemical
engineers, chemical analyst, laboratory technician, researchers etc who get paid when they work.

EXERCISE
(1) List down four careers in which chemistry is applied
(2) Mention any five products that are chemically manufactured.
(3) Explain seven areas where chemistry is applied.
(4) Explain the roles of chemistry in the following fields
(a) Agriculture (b) Human health (c) Manufacturing industries (d) Transport
(e) Communication
(5) What are the chemical substances used in agriculture? Give any four (04) materials
(6) What is the role of chemistry in overcoming health problems?
(7) Use relevant examples to support statement, “Agriculture and chemical industry can work together
rather than separate.”
(8) In what ways have modern societies benefited from chemistry through communication and advancement
of technology?
(9) How does the application of chemistry contribute to a clean environment?
(10) Explain how chemistry principles are used in making water clean and safe?

MATTER
CONCEPT OF MATTER
Definition: Matter is anything that has mass (weight) and occupies space.
Example: stones, vegetation, air, food, water and animal bodies
Mass is a measure of quantity of matter in an object. It is measured in kilogram (kg) or grams (gm).
Matter is everything that is found within our environment such as stones, , vegetation, air, food, water and our bodies
STATES OF MATTER
There are four fundamental states of matter which are;
(i) Solid (ii) Liquid (iii) Gas (iv) Plasma

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The solid, liquid and gas states are composed of particles called atoms while plasma state is composed of charged
particles.
The liquid, gases and plasma are classified as fluids because their particles have ability to flow due to their constant
random motion.
SOLID
Solid is a substance that has definite shape and size. Solid also has definite volume. It is usually hard and not easily
deformed. Eg stone, wood, sugar, sand, paper, iron, table, charcoal, cooking pot, pencil, etc
LIQUID
Liquid is a substance which flows easily and has definite volume. A liquid takes the shape of the container holding it.
Examples of liquids are water, kerosene, petrol, diesel, spirit (alcohol), milk, blood, juice, paints, oil, etc.
GASES
Gases have no fixed shape or size. They flow easily and expand indefinitely to occupy the space in which they are held.
Examples of gases are oxygen gas, hydrogen gas, carbon dioxide, water vapour, nitrogen gas, chlorine gas, ammonia
etc.
PLASMA
Plasma is a state of matter which occurs when a gas is extremely heated to form a mixture of positively charged ions
and free electrons. Plasma is a charged gas that is less dense than solids or liquids and lacks the fixed shape and
volume.
Plasma occurs naturally in a (i) Stars and lighting
(ii) Industrial processes
(iii) manufactured products like plasm televisions (TV’s)
EXERCISE
1. What are the conditions for a substance to be called matter?
2. Why are liquids and gases categorized as fluids?
3. Describe solids, liquids and gases in terms of shape and volume.
4. Why do gases expand more than solids for the same increase in temperature?
CHANGE OF STATE IN MATTER
Matter may change its state from one form to another. This can be caused by change in temperature and pressure of
matter. For example, when heated some solids melts to liquids, while liquids changes to gas (vapour) and vapour
changes to plasma under high temperature. An example of a substance which exists all four states of matter is water.

PROCESSES INVOLVED IN CHANGES OF STATES OF MATTER

(i) Melting and freezing
Melting
Melting is a process in which a substance changes from a solid to liquid.
When a solid is heated, the particles gain energy and vibrate fast and finally they break free from their fixed position
and begin to move in clusters.
MELTING POINT is the temperature at which the solid changes to liquid at standard temperature and pressure.
For example, melting point of ice (water) is 0oC. Substances with strong force of attraction between their particles have
high melting points and the ones with weak force of attraction between particles have low melting point.
Freezing
Freezing is the process in which a substance changes from a liquid to a solid on cooling.
FREEZING POINT is the temperature at which a liquid change to a solid.
For example, the freezing point of water is 0oC.
(ii) Evaporation (Vapourization)/ boiling and condensation
Evaporation
Evaporation (vapourization) is a process of changing liquid to gas (vapour) on heating at any given
Temperature
When a liquid is heated, the particles move faster as their average kinetic energy increases. Some of the
particles at the surface of the liquid gain enough kinetic energy and escape into the air.
Boiling
Boiling is a change of state of matter from liquid to (gas) vapour state at a particular temperature.
The temperature at which the liquid starts to boil is called boiling point.
Definition: Boiling point is the temperature at which the vapour pressure of the liquid is equal to the
atmospheric pressure.
NB: Boiling point of a liquid is affected by atmospheric pressure. Liquids have low boiling points at low pressure and
high boiling points at high pressure.
DIFFERENCES BETWEEN EVAPORATION AND BOILING

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 Evaporation Boiling
1.Occurs at all temperatures Occurs at one particular temperature (boiling point)
2.Occurs on the surface of the liquid Occurs both inside and on the surface of the liquid
3.Takes place slowly Takes place (rapidly) faster
4.Bubbles are not necessarily formed Bubbles are formed
NB: The boiling point of a liquid is affected by the atmospheric pressure. For example at low temperature water
may vapourize even at room temperature, ie it boils at very low temperature.
Condensation-
Condensation is the process of changing gas to liquid on cooling.
(iii) Sublimation and deposition.
Sublimation
Sublimation is a process of changing solid directly to gas without passing through liquid on heating.
Deposition
Deposition is the process of changing gases directly to solid without passing into liquid state on
cooling.
(iv) Ionization and deionization
Ionization
Ionization is a process which occurs when neutral atoms lose electrons forming ions (charged particles).
Ionization occurs when a gaseous state of matter is subjected to a very high temperature.
Deionization
Deionization is the recombination of free ions and electrons of the plasma to form atoms that finally combine to form
gas molecules.
OR
Deionization is a process which occurs when the ions and free electrons in the plasma recombine to form neutral atoms
or molecules.
Deionization occurs when temperature is decreased.

SUMMARY ON THE CHANGES OF STATE OF MATTER FOR FOUR STATES

SUMMARY ON THE CHANGES OF STATE OF MATTER FOR ONLY SOLID, LIQUID AND GAS

OR

EXERCISE
1. Describe melting and freezing according to the states of matter
2. What do you understand by the following terms
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 (i) Melting (ii) Freezing (iii) Boiling (iv) Evaporation (v) Sublimation
(vi) Deposition
3. Explain the differences between evaporation and boiling.
4. Why do cold foods not smell from a distance?
5. Differentiate between sublimation an deposition
MPORTANCE (SIGINIFICANCE) OF CHANGE IN STATE
The following are the importance of change in state of matter in our daily lives:
1. WATER CYCLE (FORMATION OF RAIN)
Water cycle is the movement of water on, above and below the earth’s surface. In water cycle water changes from
liquid to vapour by evaporation, from vapour to clouds by condensation and finally clouds to rain. Therefore, rain is
formed mainly through evaporation and condensation
2. DRYING OF MATERIAL)
Drying of materials occurs through evaporation whereby the liquid contained in the material changes to vapour. For
example, drying of clothes and food stuffs such as vegetables, cassava and maize. Farmers in the village often spread
crops on the ground to dry.
Evaporation is also used to dry wet clothes suspended on a cloth line as a result of the heat produced by the sun.
3. REFRIGERATION / AIR CONDITIONS
Refrigerators use refrigerants which are chemicals whose change in state involves the change in energy. The change of
state of refrigerants from liquid to vapour absorbs heat from the surroundings and thus causing the cooling. Air
conditions work in the same way
4. STEAM ENGINES
Steam engines use steam as working fluid to perform work. The change of state from liquid water to steam makes steam
engines to operate. Steam engines were used in early trains and ships.
5. METALLURGY (PURIFICATION OF METALS)
Metallurgy involves the extraction and purification of metals from their ores and the manufacture of alloys. The change
of state from solid to liquid and from liquid to solid make metallurgy possible.
6. SEPARATION OF MIXTURES
Different mixtures can be separated by processes such as distillation, sublimation, evaporation and condensation eg A
mixture of two or more substances with different boiling points e.g. water and alcohol can be separated by fractional
distillation which involves evaporation and condensation.
7. REFINERY
Petroleum refinery and distillery work under the principle that the liquids can change to vapour and then vapour can be
cooled to liquids. While simple distillation is used in distilleries, fractional distillation is applied in petroleum refineries.
8. PRODUCTION OF ELECTRICITY.
Coal is used to heat water in closed system of pipes into vapour. The produced vapour is led by pipes to drive the
turbines that in turn produce electricity
9. COOLING OF OUR BODIES IN HOT WEATHER
During hot weather, our bodies perspire a lot (undergo sweating). When water evaporates from the body, it takes up
heat. This brings about the cooling effect, as heat is lost from the body surface.
EXERCISE
1. Explain the roles of temperature in the changes of states of matter
2. Why do cold foods not smell from distance?
3. Provide real world examples of how the knowledge of changes in states of matter is applied in industries.

PARTICULATE NATURE OF MATTER

Matter is made up of particles. This was proved by the phenomenon known as Brownian motion.
Brownian motion.
In 1827, a botanist called Robert Brown observed through a microscope that pollen grains suspended in water moved
short distances in an irregular zigzag manner.
This is because they are constantly bombarded by particles of water which cannot be seen even through a laboratory
microscope. This shows that matter is particulate in nature.
Brownian motion state that “Matter is made up of tiny particle that are in a state of continuous random motion”
Other examples which show that matter is made up of particles that are in constant motion include (i) The spread of the
smell of the food being cooked from the kitchen to considerable distance,
(ii) Diffusion of potassium permanganate particles in water
(iii) The spread of perfume due to diffusion of perfume vapour into the air.
Diffusion is the movement of particles from an area of high concentration to the area of low concentration.
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 BEHAVIOUR OF PARTICLES IN MATTER
All matters are made up of small particles. The behaviour of these particles differs in the three states of matter. In solids
particles are firmly packed, in liquid particles are close together while in gas particles are far apart as can be seen in the
diagram below.

Properties of Solid state

(i) Particles very closely (firmly) packed together
(ii) Has definite shape and volume
(iii) Has strongest inter-particle force
(iv) Particles are not free to move
(v) Particles cannot be compressed.
(vi) Particles vibrate in fixed position.
(vii) Has high forces of attraction between the particles
(viii) It does not flow
Properties of Liquid state
(i) Particles are close together
(ii) Have definite volume
(iii) Does not have definite shape, it takes the shape of the container
(iv) Has medium density due to medium volume
(v) Molecules in a liquid can move in all direction with medium motion
(vi) Inter-particle force is weak
(vii) It can flow easily.
(viii) Particles in liquids cannot be compressed because are close together
Properties of Gas state
(i) Particles are far apart from each other
(ii) Has no definite shape
(iii) Has no definite volume
(iv) Particles have largest distance from each other
(v) Has low density due to largest volume
(vi) Has weakest inter particle force
(vii) Particle moves in all directions with high speed
(viii) The particles are randomly arranged.
(ix) It can flow easily.
(x) Particles in gases can be compressed because are far apart.
Properties of plasma state
(i) Has no definite shape
(ii) Has no definite volume, takes volume its container
(iii) Particles move freely like in gas and are highly energetic
(iv) Particles can flow easily

THE TABLE BELOW IS NOT COMPLETE

SUMMARY OF THE PROPERTIES OF MATTER
PROPERTIES SOLID LIQUID GAS PLASMA
Shape Has fixed shape Takes shape of its Has no definite Has no definite
container shape, fills the shape, fills the
shape of the shape of the
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 container container
Volume Has a fixed volume Has a Fixed Takes volume of its Takes volume of its
volume container container
Movement of Particles do not move Particles move or Particles move Highly energetic
particles except vibrations slide past one randomly in all freely moving and
another directions regularly colliding
particles
Compressibility Generally Relatively Highly Highly
incompressible incompressible compressible compressible
Space between No free space Little free space A lot of free space Highly variable
particles between particles between particles between particles depending on the
type of plasma
Electrical Poor electrical Some liquids Poor electrical High electrical
conductivity conductivity, can conduct conductivity due conductivity
except for electricity, but to lack of free because there are
conductive solids generally lower electrons free electrons
like metals than metals present
Flow Does not flow easily Flow easily Flow easily Flows easily
KINETIC THEORY OF MATTER
The kinetic nature of matter refers to the idea that “All matter is made up of tiny particles called atoms and
molecules that are in constant motion”.
It explains the behaviour and properties of matter in terms of the motion of its particles which determines the properties
of solids, liquids and gases.
Key points of the kinetic nature of matter are
(i) All matter is made up of tiny invisible particles (atoms and molecules)
(ii) The particles in matter are always in constant motion, i.e moving all the time.
(iii) The particles of matter are held together by force of attraction in which solids have strong
electrostatic forces.
(iv) The movement of particles is due to kinetic energy which depends on temperature
(v) Heavier particles move more slowly than lighter particles at the same temperature.
(vi) There are empty spaces between the particles of matter
NB: The idea about the way particles behave in solids, liquid and gases is called kinetic
molecular theory.
PHYSICAL AND CHEMICAL CHANGES
There are two major changes which are Physical change and Chemical changes;
Physical change affects the physical properties of matter while chemical change affects both physical and
chemical properties of matter
(a) PHYSICAL CHANGE
DEFINITION: Physical change is a change in which no new substance is formed.
This is a temporary change which involves change in physical properties of matter such as colour, shape,
Examples of physical changes include: melting of ice, freezing of water, evaporation of water, dissolving salts in water,
melting of candle wax, magnetization of iron, heating a metal (iron or wire) to red hot, crushing, tearing, condensation,
sublimation, etc
(b) CHEMICAL CHANGE
DEFINITION: Chemical change is a change in which a new substance is formed
This is a permanent change which involves changes in chemical properties of a matter
Examples of chemical changes include rusting of iron, burning of piece of paper, souring of milk, cooking of food,
decaying of meat, rotting of egg, fermentation of fruits, burning of candle etc .

DIFFERENCES BETWEEN PHYSICAL CHANGES AND CHEMICAL CHANGES

PHYSICAL CHANGE CHEMICAL CHANGE
1. No new substance is formed A new substance is formed
2. Are temporary changes Are permanent changes
3. The change is easily reversible The change is irreversible (cannot be reversed)
4. No energy is given out or absorbed Energy is given out or absorbed
5. Affects only physical properties of matter Affect both physical and chemical properties of
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 matter
6. There is no change in mass or weight of the There is a change in the mass or weight of the
substance Substance
7. Molecules are rearranged while their actual The molecular composition of a substance are
compositions remain same completely changed

RUSTING
Rusting is a chemical change that occurs on the surface of iron materials and forms reddish – brown coating.
The reddish – brown coating is called RUST.
CONDITIONS FOR RUSTING
There are three conditions necessary for rusting of iron to occur which are
(i) Iron (ii) Oxygen (iii) Water

Therefore, Iron will not rust on exposure to dry air or air-free water (water that has been boiled to expel all dissolved
air). However, iron will easily and readily rust in water that has dissolved air in it.
Diagram below shows that only the iron nail that is in contact with both water and air rusts.

Diagram to show Testing for conditions necessary for iron rusting

OBSERVATION
Nails in test tube A and D will rust. Nails in tubes B and C will not rust.
Reasons
In test tube A nails are in contact with both water and air (oxygen), hence rusting will occur.
In test tube B, iron nails will not rust because water has been boiled to remove oxygen and oil prevent oxygen from
dissolving in it
In test tube C, iron nails will not rust because they are in contact with air only. Anhydrous calcium chloride absorbs
any water in the test tube.
In test tube D, iron nails will rust but the process will take long time to occur because they are in contact with air but
the amount of water in air is less.
METHODS USED TO PREVENT RUSTING
In order to stop rusting iron should be protected from coming in contact with either water (moisture) or oxygen (air) or
both. The following are some of the methods used to prevent iron from rusting:
(i) Painting (ii) Oiling and greasing (iii) Galvanization (iv) Tin plating (v) Use of
silica gel(vi) Sacrificial protection (vii) Alloying
1. Painting- This is a process of coating iron items with a special pigment or paint. The paint coating
prevent oxygen and water from coming into contact with the iron material.
2. Oiling and greasing –This is the coating of iron with oil or grease, some machine parts cannot be
protected by painting so they use oil.
3. Galvanization: This is the process of coating iron or steel with zinc.
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 This is possible because zinc is more reactive than iron.
4. Tin plating: This is a process of coating iron/steel with tin.
5. Use of silica gel: Silica gel is a substance in the form of grains which absorbs moisture.
Silica gel prevent water from reaching iron/steel.
A small bag of silica gel is put inside bags or boxes used for storing or
carrying iron items to absorb any moisture that may cause rusting.
6. Sacrificial protection (anodizing)
In this technique the corrosion of a metal surface is controlled by making it the cathode of an
electrochemical cell.
The sacrificial metal then corrodes instead of the protected iron
7. ALLOYING
Alloys are mixtures of metals. For example, iron can be mixed with small quantities of much less reactive
metals to form an alloy called stainless steel. Stainless steel contains iron mixed with chromium, nickel and
manganese. Stainless steel does not rust. It is used to make cutlery and kitchen equipment.
NB: An alloy is a mixture of one metal with another metal or non-metal
EXERCISE
1. Classify the following as either physical or chemical changes
(a) Aluminium foil is cut into half (b) Evaporation of water from the ocean
(c) Milk turns sour (d) Wood is burnt (e) Nail or iron sheets rust
(f) Freezing of juice (g) Drying of clothes (h) Food is cooked
(i) Amatch is lit (j) Melting of ice (j) Dissolving sugar in water (k) Grinding a piece of paper
2. Explain the importance of change in state of matter (use any five (05) points)

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