Lecture 1 :The role of Chemistry
Chemistry is often called the central science because it connects other sciences, such as
physics, biology, and environmental science. It helps us understand the composition,
structure, and properties of matter, as well as the changes it undergoes during chemical
reactions. Everything around us — the air we breathe, the water we drink, and the food we eat
— involves chemistry.
In our daily lives, chemistry plays a vital role in many ways. For example, the soaps and
detergents we use are made through chemical processes. They contain surfactants, which help
remove dirt and oil from clothes and skin. Similarly, cooking is a chemical process: when we
heat food, chemical reactions occur that change its taste, color, and texture.
Chemistry is also essential in medicine. The development of drugs and vaccines requires
knowledge of chemical reactions and molecular structures. For instance, the painkiller
paracetamol is produced through chemical synthesis. In agriculture, fertilizers and pesticides
are designed to improve plant growth and protect crops from insects and diseases.
Moreover, chemistry contributes to environmental protection. Scientists use chemical
principles to develop biodegradable plastics and renewable energy sources, such as hydrogen
fuel and solar cells. Green chemistry aims to reduce pollution by creating safer, more
sustainable chemical processes.
In short, chemistry is not just a subject studied in laboratories; it is a key part of our modern
world. Understanding basic chemistry helps people make informed decisions about their
health, environment, and daily activities.
2. Vocabulary Focus
Word
Meaning
Example Sentence
Composition
What something is made of
Water’s composition is hydrogen and
oxygen.
Reaction
A process in which substances
change
Burning is a chemical reaction.
Surfactant
A substance that helps remove
dirt
Detergents contain surfactants.
Synthesis
The production of a compound
Aspirin is made by chemical synthesis.
Biodegradable
Able to break down naturally
Biodegradable plastics are better for the
environment.
3. Comprehension Questions
A. True or False
1. Chemistry is called the central science because it connects other sciences.
2. Cooking does not involve chemical reactions.
3. Paracetamol is a naturally occurring substance.
4. Green chemistry helps reduce environmental pollution.
5. Chemistry is useful only in laboratories.
B. Multiple Choice
1. Which of the following is an example of a chemical process?
a) Washing clothes
b) Reading a book
c) Running
d) Sleeping
2. What are surfactants used for?
a) Killing germs
b) Removing dirt and oil
c) Coloring fabrics
d) Producing perfumes
3. Green chemistry focuses on:
a) Making stronger acids
b) Increasing pollution
c) Creating safe, sustainable processes
d) Reducing food waste
4. Grammar Practice: Passive Voice in Chemistry
Change the following sentences into the passive voice:
1. Chemists study chemical reactions.
2. Factories produce biodegradable plastics.
3. Scientists develop new vaccines.
4. The company designs eco-friendly detergents.
(Example: Chemists study chemical reactions → Chemical reactions are studied by chemists.)
5. Writing Activity
Write a short paragraph (5–7 sentences) about:
“How chemistry affects your daily life as a student.”
Use at least three vocabulary words from the lecture.
6. Discussion Questions
1. Why do you think chemistry is called the central science?
2. What are some examples of chemistry in your home or community?
3. How can chemistry help solve environmental problems?
Answer Key
1. True or False
No.
Statement
Answer
Explanation
1
Chemistry is called the central science
because it connects other sciences.
✅ True
It connects physics, biology, and
environmental science.
2
Cooking does not involve chemical
reactions.
❌ False
Cooking involves chemical reactions (heat
changes taste, color, texture).
3
Paracetamol is a naturally occurring
substance.
❌ False
It is made through chemical synthesis.
4
Green chemistry helps reduce
environmental pollution.
✅ True
It creates safer, sustainable processes.
5
Chemistry is useful only in laboratories.
❌ False
It is used in medicine, cooking, agriculture,
and daily life.
2. Multiple Choice
No.
Correct Answer
Explanation
1
✅ a) Washing clothes
Soap and detergent use chemical
reactions to remove dirt.
2
✅ b) Removing dirt and
oil
Surfactants help water mix with
grease and dirt.
3
✅ c) Creating safe,
sustainable processes
It aims to protect the environment
by reducing pollution.
3. Vocabulary Practice (sample answers)
Word
Meaning
Example Sentence
Composition
What something is made of
The composition of air includes nitrogen and
oxygen.
Word
Meaning
Example Sentence
Reaction
A process in which substances
change
The reaction between acid and base produces salt
and water.
Surfactant
A substance that helps remove
dirt
This shampoo contains natural surfactants.
Synthesis
The production of a compound
Scientists use synthesis to create medicines.
Biodegradable
Able to break down naturally
These bags are biodegradable and safe for the
planet.
4. Grammar Practice – Passive Voice
Active Sentence
Passive Voice
1. Chemists study chemical reactions.
Chemical reactions are studied by chemists.
2. Factories produce biodegradable plastics.
Biodegradable plastics are produced by factories.
3. Scientists develop new vaccines.
New vaccines are developed by scientists.
4. The company designs eco-friendly
detergents.
Eco-friendly detergents are designed by the
company.
5. Writing Activity (sample answer)
Chemistry affects my daily life in many ways. When I cook food, chemical reactions change
its flavor and color. I also use cleaning products that contain surfactants to wash clothes and
dishes. In medicine, chemistry helps produce painkillers and vitamins that keep us healthy. As
a student, I realize that chemistry is everywhere — in the air, water, and even in the batteries
of my calculator.
✅ Vocabulary used: chemical reactions, surfactants, produce.
6. Discussion (sample ideas)
1. Why is chemistry the central science?
→ Because it connects other sciences and explains how matter behaves in all fields.
2. Examples of chemistry at home or in the community:
→ Soap making, cooking, cleaning, baking, fuel burning, fermentation, and water
purification.
3. How can chemistry solve environmental problems?
→ By developing green technologies, biodegradable plastics, and renewable energy.