Introduction to Chemistry

FIRST TERM E-LEARNING NOTES

SUBJECT: CHEMISTRY

CLASS: SS1

WEEK 1

TOPIC: Introduction to Chemistry

CONTENT:

1. Meaning of chemistry
2. Career prospects tied to chemistry
3. Application (i) Hospital (ii) Military (iii) Teaching (iv) Chemical and petrochemical industries.
4. Adverse effects of chemicals, drug abuse, poisoning,

Corrosion and pollution.

1. Scientific methods.

PERIOD 1: MEANING OF CHEMISTRY

Chemistry is the study of matter: its structure, composition, properties and the changes it undergoes.

Chemistry is one of the three main branches of pure science, the other two being physics and biology. Chemistry explains the changes that matter undergoes also deals with the composition, properties uses of matter. Some of the chemical changes which matter undergoes include; lighting a match, cooking, burning fire wood, making palm wine, rusting of nails, rotting of leaves. Chemical changes are otherwise known as chemical reactions. The knowledge of chemistry helps us to subject some matter to chemical processes thereby producing some materials for our every day today use. Such materials include: soaps, detergents, hair cream, perfumes, oil, margarine and plastics among others.[mediator_tech]

There are three main branches of chemistry: inorganic, organic and physical chemistry.

Career prospects tied to chemistry

Career prospects tied to chemistry simply mean the job opportunities that are available for the students with knowledge of chemistry. Such students can be employed with private and public sectors which include: Teaching service, health service, food processing, petroleum and petrochemical industries, manufacturing industry, extractive industry, Agriculture and Forestry.

1. Teaching services: Concern those who teach in primary, secondary schools, colleges of education and universities and even the laboratory assistants in schools and universities.
2. Health service: Involves pharmacists, biochemists, chemists, nutritionists, dieticians, doctors, nurses, medical assistants, laboratory assistants and dispensers.
3. Food processing: Food processing involves food technologists and research chemists.
4. Petroleum and petrochemical industries –Involves application of the following people; research chemists, chemical engineers and laboratory assistants.
5. Extractive industry- Involves chemists, mining engineers and geologists.
6. Manufacturing Industry: This involves research chemists and chemical engineers in the wide variety of manufacturing industries such as iron and steel works and cement factories.
7. Agriculture-Involves agricultural scientists, chemists, biochemists and physiologists who engaged in research to improve the quality and yield of crops and livestocks, and to advise farmers.

(viii) Forestry: Scientists engaged in research to preserve and improve forests and forestry products.

EVALUATION

1. Define the term chemistry.
2. Mention five changes that matter undergoes.
3. Give the uses of chemistry in our day to day life.
4. List at least five career opportunities in chemistry
5. Explain any three of the career opportunities mentioned above.

PERIOD 2: APPLICATION/ USES OF CHEMISTRY

The knowledge of chemistry can be apply in the following areas; namely

1. Hospital: The knowledge of chemistry makes it possible for people to involve in chemical research and technology which lead to production of medicine that we use today.
2. Military: The duty of the military is defense, to defend the territorial integrity of a nation or state. Military cannot effectively do this without ammunition. Chemistry contributes to the discovery and description of the theoretical bases for the behavior of chemical substances such as explosives used by the military. The gun powder used in the earliest guns was made by mixing sulphur, charcoal and potassium trioxonitrates (v), compounded by early chemists. The manufacture of smokeless powder was based upon gun cotton, which is made from cotton fibers soaked in a strong mixture of HNO₃ and H₂SO₄.
3. Teaching- chemistry teachers and lecturers in secondary schools, polytechnics, colleges of education and universities.
4. Chemical and petrochemical industries: Application chemists, research chemists, chemical engineers and laboratory assistants.
5. Space science: chemistry is not out in space exploration. In our efforts to gain more knowledge of the other planets and outer space around us, special rockets called ‘space rocket’ are sent into space. The first rocket was sent into space on October 4, 1957 by Russia. In July, 1969, Apollo II astronauts Neil Armstrong and Edwin Aldrin landed on the moon. These are made possible by science and technology.
6. Agriculture: Agricultural scientists, chemists, biochemists and physiologists engaged in research to improve the quality and yield of crops and livestock, and to advise farmers.

EVALUATION

1. Enumerate and explain five application of chemistry you know.

PERIOD 3– ADVERSE EFFECTS OF CHEMICALS

The adverse effects of existence of chemistry

The existence of chemistry brought about the existence of chemicals. The adverse effects of chemicals include; drug abuse, poisoning, corrosion and pollution.

1. Drug Abuse: simply involves wrong usage of drugs. Some of these drugs include heroin, cocaine and morphine which are used as addictive. Unscrupulous people produce and sell them at huge profits. Drug addiction is a major problem in our society, especially among young people. Many countries have imposed strict laws to control pollution and drug abuse. However, the most effective control measure is education. We must use what we learnt to improve our life and to control these abuses.
2. Poisoning: This is where chemicals are used to poison the food we eat. This happens when the chemicals used as addictive probably as preservative are added more than required or expired in the food stuff where it was added, then instead of the food stuff bringing health to our body, it turns to poison.
3. Corrosion: Corrosion of iron can also be called rusting and requires the presence of water and oxygen. Rusting can also be regarded as the slow deterioration of iron to iron (iii) oxide. This iron (iii) oxide is permeable to both air and water and cannot protect the iron from further corrosion of iron.

This rusting can be prevented by four methods.

1. Application of protective coating.
2. Application of sacrificial metal.
3. Alloying.
4. Cathodic protection.
5. Pollution: Chemical industries through the action of production pollute our environment as the smoke enters into the air, and dirts of different kinds enter into the water thereby polluting the entire environment. Specifically chemical wastes from factories and oil refineries and radioactive wastes from nuclear plants pollute our environment. Oil spillage, exhaust from motor vehicles, pesticides, fertilizers and acid rain have made our environment unclean and endangered plant and animal life. Human health is also being threatened by environmental pollution. Presently, chemists are trying to come up with a fuel that will reduce the air pollution problem. They are also modifying chemical processes to recycle chemical wastes or change them to harmless products which can be safely discharged into the surrounding.

PERIOD 4: SCIENTIFIC METHOD

This is the method the scientist used to produce different materials that exists as a result of chemistry. In the light of this, the scientists use their senses to observe what is happening around them. From a given set of observations, they see a certain pattern. This often leads to a problem which they try to solve. They put forward a reasonable explanation or hypothesis and carry out appropriate experiments to test it. Then, they carefully record their observations and the results of their experiments.

If the experiments support the hypothesis, they carry out further investigations. They discuss the hypothesis and results with other scientists in the field so that the hypothesis can be further tested. When a hypothesis has been tested and found to be correct within the limits of available evidence. It becomes a theory. A scientific law or principle is established only after the theory has been extensively tested and proven true without any exception. If the experiments give negative results, then the scientist goes back to his hypothesis and either modifies it or puts forward a new hypothesis. This way of studying a problem is known as the scientific method. It is the very foundation of all scientific discoveries.

EVALUATION

1. Mention five adverse effects of existence of chemistry in the world.
2. What do you understand by hypothesis?
3. Differentiate the terms hypothesis and theory
4. Explain fully what you understand by scientific method?

GENERAL EVALUATION

OBJECTIVE TEST:

1. Chemistry is defined as

A. a branch of knowledge which produces chemicals

B. the branch of science which deals with changes in matter

C. the oldest branch science

D. the branch of science which makes physics and biology career

1. Scientific approach to discoveries follows the order which includes:

A. Observation, hypothesis, and results

B. experiments, hypothesis and results

C. further experiments and problems solving

D. theory, negative and positive results and experiments

1. Chemical hypothesis is different from chemical law in that

A. hypothesis is a reasonable explanation to observations made while law is a statement from a scientist.

B. hypothesis is a reasonable explanation to observations while law is a statement which confirms the hypothesis after extensive tests.

C. hypothesis is not reasonable while law is reasonable.

D. none of the above

[mediator_tech]

1. Chemical changes around us includes all except;

A. rusting of iron nails

B. sieving

C. fading of coloured cloth

D. decomposing of green leaves in a compost

1. One of these professions has no need for chemistry

A. Miners

B. Engineers

C. Philosophers

D. Geologists

ESSAY QUESTIONS

1. Give five reasons why chemistry is important in your life.
2. Explain in detail two of the reasons given above.
3. List three adverse effect of existence of chemistry in this world.
4. Explain two of those adverse effects mentioned above.
5. Explain the term scientific method full.

WEEKEND ASSIGNMENT:

PRE- READING ASSIGNMENT

Read about physical and chemical changes and differentiate them.

WEEKEND ACTIVITY

Explain fully what you understand by the following terms.

Atoms, Molecules, Constituents of atoms.

REFERENCE:

1. New school chemistry for senior secondary schools by Osei Yaw Ababio revised by L.E.S. Akpanisi Herbert Igwe.