Introduction to Chemistry Class 6 Selina Exercise

Class 6 • Concise Chemistry Selina • Exercise I

Introduction to Chemistry

Learn how chemistry shapes food, clothing, buildings, medicines, industry and daily life through interactive questions, instant answers and animated revision cards.

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5 MCQs 5 Fill-ups 5 True/False Complete Answers
Laboratory glassware used for chemistry experiments
Colourful laboratory flasks representing chemistry. Image: Joe Sullivan via Wikimedia Commons, CC BY 2.0.
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Build the foundation

Quick Learn: Chemistry Around Us

What is Chemistry?

Chemistry is the branch of science that studies the composition, properties and changes of matter.

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Food Production

Fertilisers supply nutrients, while pesticides, insecticides and fungicides help protect crops.

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Industry

Chemistry supports the production of dyes, paints, plastics, fibres, steel, alloys and pharmaceuticals.

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Health

Medicines such as aspirin, paracetamol and antibiotics help prevent or treat disease.

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Clothing

Natural fibres include cotton, silk and wool. Synthetic fibres include nylon, polyester and spandex.

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Construction

Mortar, cement and steel are important building materials connected with chemistry.

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Daily Life

Soap, toothpaste, shampoo, perfume, creams and many other everyday products involve chemistry.

Accuracy and safety note: Aldrin and D.D.T. appear in older school exercises as pesticide examples. T.N.T. and gunpowder are explosives. These substances must never be handled or experimented with by students.
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Exercise I

Objective Type Questions

Your score: 0/5
Question 1(i)

Trinitrotoluene is used as:

Reason: Trinitrotoluene, commonly called T.N.T., is an explosive. Preservatives protect food from decomposition, fertilisers supply nutrients to crops, and fuels release useful heat during combustion.
Question 1(ii)

Which one of the following is a pesticide?

Reason: Aldrin is a historical example of a pesticide. Benzoic acid is mainly used as a food preservative, sugar is a food substance, and gunpowder is an explosive.
Question 1(iii)

Mortar is used as:

Reason: Mortar is commonly prepared from a binder such as cement, fine aggregate such as sand, and water. It is used to bind bricks or stones in construction.
Question 1(iv)

Urea is an important:

Reason: Urea is a nitrogen-rich fertiliser used to supply an essential nutrient to crops and improve plant growth.
Question 1(v)

The medicines prescribed by a doctor to treat certain bacterial infectious diseases are called:

Reason: Antibiotics are medicines used to treat bacterial infections. Examples include penicillin and tetracycline. They should be taken only when prescribed by a qualified medical professional.
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Exercise I

Fill in the Blanks

Type an answer and press Check. Capital letters and full stops are ignored.

(a) Chemistry   (b) Fertilisers   (c) Preservatives   (d) Cooking   (e) William Ramsay

Exercise I

State True or False

Choose an option. False statements will show the corrected sentence.

(a) Chemistry plays an important role in our national economy.

(b) Antibiotics are used as preservatives.

(c) D.D.T. is an important fertiliser.

(d) Gunpowder is an insecticide.

(e) Enzymes secreted by our body are chemicals.

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Exercise I

Match the Following

Question 4

Match Column A with Column B

Column AColumn B
(a) Clothing(i) Toothpaste, cosmetics
(b) Green Revolution(ii) Nylon, wool
(c) Building materials(iii) Agriculture
(d) Commodities of daily use(iv) Mortar, cement

(a)–(ii), (b)–(iii), (c)–(iv), (d)–(i)

Question 5

Match the scientists with their discoveries or contributions

Column AColumn B
(a) Marie Curie(i) Safety lamp
(b) John Dalton(ii) Helium
(c) William Ramsay(iii) Nobel Prize winner twice
(d) Sir Humphry Davy(iv) Atomic theory

(a)–(iii), (b)–(iv), (c)–(ii), (d)–(i)

Scientific note: William Ramsay isolated helium on Earth and co-discovered several noble gases. John Dalton is best known for developing modern atomic theory.

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Memory booster

Scientist Flashcards

Tap or click a card to flip it.

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Exercise I

Short Answer Type Questions

Question 1 Name the scientists associated with the following.

(a) Atomic theory: John Dalton

(b) Oxygen: Joseph Priestley

(c) Safety lamp: Sir Humphry Davy

(d) Modern classification and definition of elements: Antoine Lavoisier

Accuracy note: The textbook may say that Dalton “discovered atoms” and Lavoisier “discovered elements.” More precisely, Dalton developed modern atomic theory, while Lavoisier helped define and classify elements. Oxygen was also prepared independently by Carl Wilhelm Scheele.
Question 2 Give two examples of each substance.
(a) Food preservatives
Sodium metabisulphite; ascorbic acid
(b) Fuels
Petrol; diesel
(c) Fungicides
Bordeaux mixture; sulphur
(d) Medicines
Aspirin; paracetamol
(e) Building materials
Steel; cement
(f) Explosives used in defence
Trinitrotoluene (T.N.T.); gunpowder
Classification note: T.N.T. and gunpowder are explosives, not chemical warfare agents. The wording has been corrected for scientific accuracy.
Question 3 Answer in one or two sentences.

(a) What is science?

Science is the systematic study of nature through careful observation, experimentation and evidence. It helps people understand and use natural processes for meaningful purposes.

(b) What is chemistry?

Chemistry is the branch of science that studies the composition, properties and changes of matter.

(c) What is a fuel?

A fuel is a substance that releases useful energy, usually heat, when it burns. Examples include L.P.G., petrol and diesel.

(d) What is the Philosopher's Stone?

The Philosopher's Stone was a mythical substance that alchemists believed could turn base metals such as iron or copper into gold and might also provide health or immortality. No such substance has ever been scientifically shown to exist.

Question 4 Think and name six chemical products used daily.
ShampooToothpasteFace creamSoapSaltPerfume
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Mini activity

Chemistry in My Day

Tick the products you used today. Your total updates instantly.

You found 0 chemistry-linked products in your day.
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Exercise I

Long Answer Type Questions

Question 1 Name the chemicals that help increase food production.

Chemical products that help increase or protect food production include:

FertilisersPesticidesInsecticidesFungicides

Fertilisers provide nutrients to plants. Pesticides are a broad group used to control pests; insecticides control insects and fungicides control harmful fungi.

Question 2 Who is known as the Father of Chemistry? Why?

Antoine Lavoisier is widely known as the Father of Modern Chemistry. He used careful measurements and experiments to study chemical reactions, helped establish the law of conservation of mass, improved chemical naming and explained oxygen's role in combustion.

Question 3 How is chemistry helpful in improving human health?

Research in chemistry has led to the development of many medicinal drugs. These chemical substances help prevent disease, reduce symptoms or treat infections and other health conditions.

Examples include aspirin, paracetamol, antibiotics such as penicillin and tetracycline, antiseptics and disinfectants. Medicines must always be used according to professional medical advice.

Question 4 Explain alchemy, its experiments and its difference from chemistry.

(a) What is alchemy?

Alchemy was an early practice that combined experiments with philosophical and spiritual ideas. Many alchemists tried to transform common metals into gold and searched for special substances such as the Philosopher's Stone.

(b) What kind of experiments did alchemists perform?

Alchemists heated, mixed, dissolved, distilled and purified materials. Their work helped develop laboratory apparatus and practical methods for preparing substances, extracting metals, making alloys, pigments, inks, medicines and other useful materials.

(c) What is the main difference between alchemy and chemistry?

Alchemy mixed practical experiments with mystical beliefs and lacked standard methods. Modern chemistry is a systematic science based on reproducible experiments, careful measurement, evidence and a common scientific language.

Question 5 What is chemistry's contribution to different fields?

(a) Industry

Chemistry supports industrial growth and improves manufacturing processes. Industries use chemical knowledge to make dyes, drugs, paints, plastics, synthetic fibres, petrochemicals, pharmaceuticals, steel and alloys.

(b) Clothing

The textile industry converts fibres into fabrics. Natural fibres such as cotton, silk and wool are used for clothing and other products. Synthetic fibres such as nylon, polyester and spandex are used in clothes, towels, bags, bedsheets and curtains.

(c) Cosmetics

Cosmetics are products used to clean, protect or change the appearance of external parts of the body. Examples include talcum powder, skincare creams, lipstick, make-up, deodorants, lotions, perfumes, soap and bath oils.

(d) National Defence

Chemistry contributes to defence through specialised materials, protective equipment, fuels, propellants, medicines, communication materials and carefully controlled explosive substances. Such materials are handled only by trained professionals under strict safety rules.

(e) Medicines

Chemical research has enabled the discovery and production of medicines that help prevent or treat disease. Examples include aspirin, paracetamol, antibiotics such as penicillin and tetracycline, antiseptics and other pharmaceutical products.

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One-minute revision

Key Points to Remember

1

Chemistry studies matter, its composition, properties and changes.

2

Fertilisers provide nutrients; pesticides help control crop pests.

3

Preservatives slow food spoilage caused by microorganisms or chemical changes.

4

Fuels release useful energy. L.P.G. is commonly used for cooking.

5

Modern chemistry depends on evidence, measurement and repeatable experiments.

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Frequently asked questions

Introduction to Chemistry FAQs

What is chemistry for Class 6?

Chemistry is the branch of science that studies matter, its composition, properties and the changes it undergoes.

How does chemistry help in food production?

Chemistry provides fertilisers that supply plant nutrients and crop-protection chemicals such as insecticides and fungicides.

Why are preservatives added to food?

Preservatives help slow spoilage and protect food from microorganisms or unwanted chemical changes, increasing its usable life.

Who is called the Father of Modern Chemistry?

Antoine Lavoisier is widely called the Father of Modern Chemistry because he introduced careful measurement into chemical experiments and helped establish important principles and naming systems.

What is the difference between alchemy and chemistry?

Alchemy combined experiments with mystical beliefs. Chemistry is based on evidence, standard methods, careful measurement and repeatable experiments.

What are six chemistry-related products used daily?

Examples include shampoo, toothpaste, face cream, soap, salt and perfume.

Chapter Complete!

Revise the scientist flashcards and retry the quiz until you score 5/5.

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Concept by Teacher Ritu, designed by Shaleen Shekhar.
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