Development of Chemistry Class-6th Goyal Brothers Chemistry Solutions Ch-1 unit-2

Development of Chemistry Class-6th Goyal Brothers Chemistry Solutions Chapter-1 (unit-2). We Provide Step by Step Answers of Objective, True False , Fill in the blanks, Match the following , Study Questions of Chapter- 1, Introduction to Chemistry, Unit-2 (Development of Chemistry). Visit official Website  CISCE  for detail information about ICSE Board Class-6.

Development of Chemistry Class-6th

Goyal Brothers Chemistry Solutions Chapter-1 unit-2

Board ICSE
Class 6th
Subject Chemistry
Book Name Goyal Brothers
Theme-1 Importance to Chemistry
Unit-2 Development of Chemistry
Topic Solution of exercise questions
Session 2023-24

OBJECTIVE TYPE QUESTIONS

Chemistry Solutions Chapter-1 unit-2

A. Fill in the blanks :

  1. Magic is something which cannot be explained by scientific _innovation_.
  2. Sodium sulphate is also known as _Glauber’s_ salt.
  3. The different cosmetic products have a strong component of scientific _reason_.
  4. Polymer chemistry has contributed to _clothing_ technology.
  5. _Rayon_ is sometimes called regenerated fibre.

B. Statement given below are incorrect. write the correct correct statement:

1. Flavour chemists use knowledge of the chemistry of fragrance and create new and improved perfume for mankind.

Correct Statement: Flavour chemists use knowledge of the chemistry of food ingredients and create new and improved perfume for mankind.

2. Detergents are used to remove stains caused by rust.

Correct Statement: Lemon juice are used to remove stains caused by rust.

3. Nylon has a feel and texture of natural silk.

Correct Statement: Rayon has a feel and texture of natural silk.

4. Rayons are compounds formed, when alcohol is made to react with organic acids.

Correct Statement: Rayons are compounds formed, when wood or pure cotton treated with chemical.

5. Quinine is an example of medicine made from the animal product.

Correct Statement: Quinine is an example of medicine made from the bark of a plant.

C. Match the statement in Column A with those in Column B:

Column A

Column B

1. Something which cannot be explained by scientific reason.

(a) John dalton

2. The chemistry which has contributed to clothing technology.

(b) Rayon

3. The fibre known as regenerated fibre.

(c) Magic

4. A branch of chemistry which has also contributed to clothing technology.

(d) Polymer chemistry

5. A chemist who is the best recognised for his work onthe atomic theory and research on colour blindness.

(e) Dye chemistry

Answer:

Column A

ColumnB

1. Something which cannot be explained by scientific reason.

(c) Magic

2. The chemistry which has contributed to clothing technology.

(d) Polymer chemistry

3. The fibre known as regenerated fibre.

(b) Rayon

4. A branch of chemistry which has also contributed to clothing technology.

(e) Dye chemistry

5. A chemist who is the best recognised for his work onthe atomic theory and research on colour blindness.

(a) John dalton

D. Write ‘True’ or ‘False’ for the following statements :

  1. Food chemists work with plants that have been harvested for food and animals which are useful to humans. [T]
  2. Man has been independent on medicinal plants in ancient time. [T]
  3. A solvent or detergent is generally used to remove stain. [T]
  4. Forensic scientists work for finance department for giving proper advice regarding economic policy. [F]
  5. Henry Cavendish discovered hydrogen and composition of water. [F]

E. Tick (√) the most appropriate answer.

1. Which of the following chemical compounds is used to improve our appearance :

(a) Medicines

(b) Cosmetics

(c) Adhesives

(d) All of these

Ans: (b) Cosmetics

2. Which of the following artificial fibre is known a sartificial silk?

(a) Rayon

(b) Nylon

(c) Polyester

(d) Acrylon

Ans: (a) Rayon

3. The analgesic drug is generally known as :

(a) antibiotic

(b) paracetamol

(c) pain killer

(d) antimalerial

Ans: (c) pain killer

4. Which of the following chemists discovered oxygen’s role in combustion and respiration?

(a) Henry Cavendish

(b) Antoine Lavoisier

(c) Dmitri Mendeleev

(d) Robert Boyle

Ans: (b) Antoine Lavoisier

5. Which of the following chemists recognised for his work in atomic theory and research on colour blindness?

(a) John Dalton

(b) Robert Boyle

(c) Henry Cavendish

(d) Antoine Lavoisier

Ans: (a) John Dalton

STUDY QUESTIONS

Question 1. Write a short note on development of Chemistry- a historical perspective.

Answer: Chemistry took its present scientific form in the 18th century, when careful quantitative experiments by Lavoisier, Proust, and Dalton resulted in the law of definite proportions, the law of conservation of mass, and the law of multiple proportions, which laid the groundwork for Dalton’s atomic theory of matter.

Question 2. How does chemistry help in the production of food ?

Answer: Chemical substances can play an important role in food production and preservation. Food additives can, for example, prolong the shelf life of foods; others, such as colours, can make food more attractive. Flavours are used to make food tastier. Food supplements are used as sources of nutrition.

Question 3. How can you say chemistry plays a vital role in the production of cosmetics ?

Answer: Chemistry plays a significant role in the development of cosmetics because it is the science of understanding the properties and behavior of chemicals, which is essential in the formulation, production, and testing of cosmetics.

Question 4.

(a) Define polymer chemistry.

Answer: Polymer Chemistry, which includes the study of polymer materials and polymerisation, has successfully synthesised new polymers, investigated polymerization processes, and characterised the structure and properties of polymeric materials.

(b) Write at least three synthetic fibres and explain their properties and uses.

Answer: The three synthetic fibres are-

  • Rayon or artificial silk: The filament of rayon can be woven like any other natural fibres. They have a feel and texture of natural silk. It is used in textile industry for making clothing like sarees, blouses, dresses, socks, etc.
  • Nylon: These are elastic, strong for rope climbing and fishing nets. and water resistant. It is used for making common household articles.
  • Polyester: Polyester is a synthetic or man-made fiber material. These are used for making sails for for sailing boats, fire hoses and conveyor belts.

Question 5. How does chemistry help in medical applications? Explain properly.

Answer: Chemistry contributes to the preparation and use of materials for surgery (sutures, artificial skin, and sterile materials). It plays a huge role in the development of synthetic drugs such as antibiotics, antimalarials and analgesics (pain killers).

Question 6.

(a)Define industrial chemistry.

Answer: Industrial chemistry is the branch of chemistry that deals with the development and application of chemical processes used in industry. This can include the production of chemical products, such as plastics, fertilizers, and pharmaceuticals, as well as the development of new materials and technologies for use in manufacturing and other industrial applications.

(b) What do you mean by stain removal ? Write atleast three stain removers and their proper applications in removing the stain.

Answer: A process of removing a spot left by one substance on a fabric is called stain removal.

The three stain removers are –

  • Household bleach: It contains hydrogen peroxide which can be used to remove common stains.
  • Detergents: It is used for removing stains, oil spots, ets.
  • Lemon juice: It contains citric acid as bleaching agent. It can remove stains caused by rust.

Question 7. List atleast three notable persons and mention their contribution to chemistry.

Answer: The notable persons and their contribution to chemistry are-

  • Henry Cavendish: He discovered hydrogen and the composition of water.
  • John Dalton: The atomic theory and research on colour blindness are best recognised works of John Dalton.
  • Robert Boyle: He proved that sound does not ravelled in vacuum. He discovered Boyle’s law. He worked on flame test and acid base indicator.

— : end of Development of Chemistry Class-6th Goyal Brothers Chemistry Solutions Ch-1 unit-2 :–-

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