CHAPTER 1

INTRODUCTION TO CHEMISTRY

The concept of chemistry

KEY TERMS AND CONCEPTS.

  • Chemistry- this is the study of composition and decomposition of matter

  • Composition- this is making up of matter from simple substances

  • Decomposition- this is the breaking up of matter

  • Scientist- is a person who studies science

  • Chemist- is an individual who studies chemistry

  • Alchemists- are individuals who used to study chemistry long time ago.

  • Matter is anything that has got weight and occupies space.



  • Chemistry is a branch of science that deals with the properties of matter. Matter is anything that has got weight and occupies space.

  • Examples of matter include stones, air, dust, papers, charcoal, animals, plants and all other things that surround us. Chemistry basically deals with how matter behaves under certain conditions.

  • That is why we define chemistry as a branch of science that deals with composition and decomposition of matter.

  • By composition we mean what makes up matter for example charcoal is made up of carbon element. The way charcoal reacts for example with air gives its properties.

  • On the other hand decomposition deals with the breaking up of matter into small components. For example the chalk we use to write is made up of carbon, calcium and oxygen, which forms a compound called calcium carbonate.

  • When this compound is heated; it will break down into carbon dioxide gas and calcium oxide, this is an example of decomposition.

  • Chemistry is one of the branches of science. Science is divided into other disciplines such as mathematics, physics, biology, astronomy among other.

  • A person who studies science is called a scientist. People who studies chemistry on the other hand are called chemists.

  • Chemists study chemistry so that they can use the knowledge to apply in other areas of life like making of new products.

Origin of chemistry

  • Chemistry has existed since time immemorial. In the old days people have been practicing chemistry without knowing.

  • The father of modern chemistry is however thought to be Antoine Lavoisier. He comes up with modern ways of studying chemistry.

  • Earlier on some people tried to study chemistry in a very crude way. For example, some tried to convert metals such as iron into precious elements like Gold and silver.

  • These individuals did not however follow scientific procedures and were relying on witch-craft.

  • They were called alchemists and did not succeed in their work, because they did not follow the right scientific procedures.

The importance of studying chemistry

The study of chemistry is very important to you as a student because;

  1. Through the study of chemistry, you can enter into various careers.

  2. Chemistry assists us to answer some fundamental questions like why iron undergoes rusting.

  3. Through knowledge of chemistry we get various materials which make our life simpler.

  4. Chemistry has contributed a lot in the conservation of the environment

  5. We can be able to gain scientific skills through the study of chemistry

  6. Chemistry is fun, stimulating and interesting to study.





Application of chemistry

  • Chemistry has been responsible for conversion of natural substances which exists in nature into useful substances.

  • Can you mention some of the things we make use of which are made by the application of chemistry knowledge?

Areas where the knowledge of chemistry is applied

The knowledge of chemistry has found applications in various fields such as a follows;

  1. Food industry

  • The knowledge of chemistry has been used to develop various kinds of food substances which has improve our diets and helped fight malnutrition.

  • The role of food in our bodies is better understood through the knowledge of chemistry. Chemistry knowledge is also applied in the preservation of food for future use.

  1. House hold products

  • Materials such soaps, detergents, bleaches and disinfectants are made using the knowledge of chemistry.

  • These products are useful in cleaning of our homes, schools, hospitals and other buildings.

  • Compounds called synthetic polymers commonly known as plastics. From plastics we get fibers for making cloth materials.

  • However these products tend to harm our environment.

  1. Health care product

  • Chemists study how drugs and vitamins can help or harm our bodies. They search also for new medicines and vaccines.

  • Medicines are used to treat diseases while vaccines are used to prevent them.

  • The process of introducing vaccines in our bodies is called vaccination.

  • The knowledge of chemistry is used to perform various tests on items we use every day to ensure that they meet quality standards.

  • Such things include food, water, and medicine, building materials, electrical equipment and household items.

  1. Environment

  • Chemistry knowledge is used to eliminate possible effects of items made through the use of chemistry knowledge.

  • Knowledge of chemistry has been applied in the treatment of sewage

  • The scientists can also know to produce useful things without harming the environment.

  1. Manufacturing industry

  • Chemistry knowledge has been used to make various industrial products which have great use in our daily life.

  • These items have made life simpler and enjoyable to live. Items which are made using chemistry knowledge from the industry include mattresses, bed sheets, paints, sugar, cars, chemicals, planes, drones, bicycles, motor-cycles.

  1. Agriculture

  • Fertilizers, herbicides, fungicides, drugs for livestock, are made using knowledge of chemistry.

  • Chemists also study soil and advice farmers what type of plants can do well in such soils.

  1. Transport

  • The transport industry depends heavily on the work of chemists and chemical engineers.

  • These people work in processing industries to produce various products for the transportation industry.

  • These products include petrol, diesel, gas, lubricating oil for running machinery and rubber for making tires.

  • Transport infrastructure has been made possible through application of chemistry

  1. Energy production

  • Chemists work in industries to find ways of producing cheaper sources of energy and clean energy which does not harm the environment.

  • They also research on effects of using various energies to the living organisms and the environment.

Q. Can you think of other areas where knowledge of chemistry is applied?

Where do we find chemistry?

Chemistry can be found in various places in our society. These include the following;

  • Homes- in our homes the knowledge of chemistry is applied in cooking of food in the kitchen.

  • Research institutions- in government research institution you will find chemists working on new products such as drugs.

  • In universities and colleges- universities and colleges are centers of research and here you will find modern laboratories where research work is done

  • Schools- in school laboratories we can also find chemistry work been undertaken.

END OF TOPIC QUESTIONS.

  1. An intelligence guess to possible answer on a problem is called

  1. Statement

  2. Hypothesis

  3. Conclusion

  4. Experimentation

  1. The following skills acquired through studying chemistry except;

  1. Careful observation

  2. Accurate reporting

  3. Testing hypothesis experimentally

  4. Map reading skills

  1. Chemistry is a scientific activity because;

  1. Chemistry is studied in schools

  2. Chemistry is interesting subject studied through data collection and analysis.

  3. Knowledge of chemistry is acquired through observation, experimentation and logical reasoning.

  4. It involves study of living and non living things.

  1. Which of the following takes place in experimental stage?

  1. Rejection of hypothesis

  2. Acceptance of hypothesis

  3. Concluding the scientific findings

  4. Carry out investigations



  1. In scientific procedure, what would be the next step to follow after experiments?

  1. Data interpretation

  2. Conclusion

  3. Observation

  4. Investigation

  1. What should a scientist do if he/she obtain results from an experiment which do not support his/her hypothesis? He/ she should;

  1. Change the experiment

  2. Leave out the results

  3. Give ideas for further testing to find a solution

  4. Identify a new problem

  1. Which branch of science deals with the composition and decomposition of matter?

  1. Chemist B. Biologist C. Chemistry D. Chemical change

  1. The second step in scientific procedure is ………………

  1. Data collection and analysis

  2. Conclusion drawing

  3. Formulation of hypothesis

  4. Experimentation and observation

  1. What best knowledge can be used by industrialists to manufacture chemicals

  1. Methods of separating mixtures

  2. Debate on drug abuse

  3. Campaigns on elections

  4. Labeling apparatus for experiments

  1. What name is given to people who study chemistry?

  1. Scientists B. Chemistry students C. Pharmacists D. Chemists

  1. The first step in the scientific procedure is ………….

  1. Data analysis

  2. Problem identification

  3. Hypothesis formulation

  4. Data interpretation


  1. If the results you obtained from an experiment do not support your hypothesis

  1. Change you experiment

  2. Leave out the results

  3. Identify a new problem

  4. Give ideas for further testing to find a solution


  1. A chemist should acquire the following skills except ……………..

  1. Problem identification C. Observation

  2. Experimentation D. Surgery


  1. Chemicals sprayed or sprinkled on crops to destroy pests are called;

  1. Fertilizers B. Pesticides C. Insecticides D. Weed killers

  1. Chemistry helps us to explain

  1. Why and how matter undergoes changes

  2. What medicine to use when are fall sick

  3. How chemicals are used in agriculture

  4. How pesticides help in crop population


  1. A simple proof that chemical reactions takes place in our bodies is that

  1. We occasionally fall sick

  2. Doctors tell us in the hospital

  3. The food we eat or drinks we take are quite different from the waste products from our bodies

  4. We eat a balance diet.


  1. Which of the following is not a list of products of application of chemistry?

  1. Tables, chairs and bricks

  2. Shoes polish, antiseptics and toothpaste

  3. Soap, medicinal and perfume

  4. Fertilizer, pesticides and herbicides


  1. Chemistry is a scientific activity because

  1. Chemistry is studies in schools

  2. It’s an interesting subject

  3. Knowledge of chemistry is acquired through observation

  4. Knowledge of chemistry is acquired through experiment and logical reasoning

  1. Factors in an experiment that can be manipulated to get desired result is called;

  1. Controlled variables

  2. Manipulated variables

  3. Dependent variables

  4. Independent variables

  1. The following skills acquired through studying chemistry except;

  1. Careful observation

  2. Accurate reporting

  3. Testing hypothesis experimentally

  4. Map reading skills

  1. Chemistry is a scientific activity because;

  1. Chemistry is studied in schools

  2. Chemistry is interesting subject studied through data collection and analysis.

  3. Knowledge of chemistry is acquired through observation, experimentation and logical reasoning.

  4. It involves study of living and non living things.

  1. Which differentiates chemistry from other subjects? It is a study of

  1. Matter in relation to energy

  2. The behaviour of matter

  3. Living and non living things

  4. Chemical properties of matter

2. State three areas where chemistry knowledge is applied in day to day life; and give TWO examples in each area.


Area

Example

i.


ii.


iii.


  1. List any fives careers in which chemistry is an important subject;

  1. …………………………………………………………………………………………………

  2. ………………………………………………………………………………………………….

  3. ………………………………………………………………………………………………….

  4. ………………………………………………………………………………………………….

  5. …………………………………………………………………………………………………..

  6. ………………………………………………………………………………………………….


  1. Make list of three products made by application of chemistry in manufacturing industry;

  1. …………………………………………………………………………………………………

  2. …………………………………………………………………………………………………

  3. …………………………………………………………………………………………………..


  1. Write T for correct statement and F for incorrect statement in the space provided;

  1. A chemist should have knowledge of surgery …………………..

  2. Vaccines are chemical substance that is used to produce vitamins and proteins in animals ………..

  3. First aid helps us to save life. ……………


  1. Explain how chemistry is applied in the following field?

  1. Communication ________________________________________________________________________________________________________________________________________________________________________________

  2. Transportation ________________________________________________________________________________________________________________________________________________________________________________


  1. (a) Define the following terms;

  1. Hypothesis ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

  2. The Scientific procedure ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

  3. Flame ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

(b) Write down only four applications of chemistry;

i. …………………………………………………………………………………………………

ii. …………………………………………………………………………………………………

iii. ………………………………………………………………………………………………..


  1. Name six agriculture materials made by the application of chemistry;

  1. ……………………………………………………….

  2. ……………………………………………………….

  3. …………………………………………………..........

  4. ………………………………………………………..

  5. ……………………………………………………….

  6. ……………………………………………………….

  1. Indicate true T, of false F for the following statement;

  1. It is not wise to take medicine before medical test. ……………

  2. Experiments are there to find answers to scientific problems ………………..

  3. Hypothesis are true statements after long term experiments. ……………….

  4. A suitable experiment must consider the factors that may affect the problem under investigation. ………………

  5. The scientific procedure is only used in project work. ……………

  6. A conclusion can be made even before data interpretation …………….



SUMMARY

  • Chemistry is a branch of science that deals with the properties of matter. Matter is anything that has got weight and occupies space.

  • Chemistry is defined as a branch of science that deals with composition and decomposition of matter.

  • Chemistry is one of the branches of science. Science is divided into other disciplines such as mathematics, physics, biology, astronomy among other.

  • A person who studies science is called a scientist. People who studies chemistry on the other hand are called chemists.

  • Chemists study chemistry so that they can use the knowledge to apply in other areas of life like making of new products.

  • The father of modern chemistry is however thought to be Antoine Lavoisier. He comes up with modern ways of studying chemistry.

  • The study of chemistry is very important to you as a student because;

  • Through the study of chemistry, you can enter into various careers.

  • Chemistry assists us to answer some fundamental questions like why iron undergoes rusting.

  • Through knowledge of chemistry we get various materials which make our life simpler.

  • Chemistry has contributed a lot in the conservation of the environment

  • We can be able to gain scientific skills through the study of chemistry

  • Chemistry is fun, stimulating and interesting to study.

  • The knowledge of chemistry is applied in areas such as food industry, petroleum industry, manufacturing, making household items etc.

  • We can find chemistry being applied in homes, schools, research centers and even in hospitals.





SAMPLE NECTA QUESTIONS ON TOPIC



  1. Chemistry is one of the science which deals with

  1. Alkalinity and basicity of substance

  2. The study of body cells

  3. Composition, properties and behavior of matter

  4. Chemical changes (2003)

  1. In chemistry experiments test

  1. Data

  2. Problem

  3. Hypotheses

  4. Observation(2005)

  1. When a chemist studies a substance, he/ she is interested in its

  1. Force of attraction

  2. Shape

  3. Smell

  4. Properties (2007)

  1. A chemist should acquire all of the following skills except

  1. Experimentation

  2. Observation

  3. Problem identification

  4. Surgery (2012)

  1. A chemistry defined as

  1. The scientific study of matter, compound, and chemical reaction

  2. The scientific study of compounds, mixture and organic substances

  3. The scientific study of composition structure and properties of matter

  4. The study of relation between human being, medicine, and pollution (2016)







TOPICAL EXAMINATION

INTRODUCTION TO CHEMISTRY

EXAMINATION SERIES FOR SECONDARY SCHOOL REVISION

SECTION A 20 MARKS

  1. MULTIPLE CHOICE QUESTIONS

  1. The term chemistry means;

  1. Study of nonliving things

  2. Study of physical properties of matter

  3. Study of drugs

  4. Study of composition and decomposition of matter

  1. Substances studied in chemistry are made up of;

  1. Compounds

  2. Matter

  3. Chemicals

  4. Element

  1. Which is not an importance of studying chemistry;

  1. Understand how matter undergo chemical change

  2. Make various medical products

  3. Understand the use of chemicals in agriculture

  4. Help us enter into various careers.

  1. A mother at home can apply chemistry to;

  1. Weed flowers in the garden

  2. Dusting the floor of her house

  3. Weighing maize flour

  4. Cooking food in the kitchen

  1. Which of the following illustrates a chemical reaction taking place in our body

  1. Falling sick

  2. Digestion

  3. Respiration

  4. Salivating

  1. Which of the following is not a list of application of chemistry?

  1. Table, chairs and Bricks

  2. Shoe polish, antiseptics and toothpaste

  3. Soap, medicinal drugs and perfumes

  4. Fertilizer, pesticides and herbicides

  1. Which of the following careers does not require the knowledge of chemistry?

  1. Medicine

  2. Agriculture

  3. Archeology

  4. Pharmacy

  1. Identify the skill not acquired during chemistry study

  1. Careful observation

  2. Accurate reporting

  3. Testing hypothesis experimentally

  4. Map reading skills

  1. Individuals who studied chemistry long time ago were called

  1. Alchemists

  2. AL chemistry

  3. Witch doctors

  4. Chemists

  1. Chemistry is list related to;

  1. Biology

  2. History

  3. Physics

  4. Geography

  1. MATCHING ITEMS QUESTIONS.

LIST A

LIST B

  1. Study of matter

  2. Wanted to convert metals into precious metals

  3. Sense not commoly used in laboratory

  4. Deals with making and dispensing of drugs

  5. Deals with study of living and non -living things

  6. Breaking up of matter

  7. A person who studies chemistry

  8. Anything that has got mass and occupies space

  9. A chemical applied in plants to supply nutrients

  10. Deals with development of new products.

  1. Engineering

  2. Technology

  3. Alchemist

  4. Fertilizer

  5. Eyes

  6. Tongue

  7. Composition

  8. Decomposition

  9. Chemist

  10. Pharmacy

  11. Nursing

  12. Medicine

  13. Matter

  14. Atom

  15. Chemical engineer

  16. Science

  17. physics



  1. Write T for true statement and F for a False statement.

  1. There are only two branches of science

  2. Chemistry has little application in our life

  3. Through chemistry, development of modern technology is made possible

  4. We only study chemistry to enter into careers

  5. Chemistry is only studied by chemists

b) Fill in the spaces below;

i) The field of science that deals with crop production and livestock management is called……………

ii) Ink, shoe polish, paper, clothes and rubber are examples of things produced from application of knowledge of…………………………………………………….

iii) Study of chemistry prepares people for different skills needed in our daily life such as………….

iv) Chemicals used to kill insects are called………………………………………………………..

v) The study of matter and its properties is called…………………………………

  1. A) mention three branches of science

b) Who is a chemist?

c) List 5 places where chemistry is applied

d) Name three cleaning agents made by chemistry knowledge



  1. Explain how chemistry is applied in the following;

  1. Health

  2. Agriculture

  3. Energy production

  4. Transport

  5. Modern technology

  1. Mention four importance of studying chemistry

  2. Mention two items used in each of the following categories that are made through application of chemistry

  1. Agriculture

  2. Pharmaceutical

  3. Household items

  4. Food and beverages

  5. Transport

b) Chemistry has contributed to environmental hazards. Briefly explain how



  1. a) Who are alchemists?

b) What was the aim of alchemists?

c) Briefly explain how chemistry has contributed to good life



  1. a) Mention areas where chemistry is applied.

b) Mention five careers one can enter by studying chemistry.



  1. a) mention two branches of chemistry

b) Differentiate chemistry from physics.



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