Introduction to Chemistry Class-6 Dalal Simplified ICSE Chemistry Solutions Chapter-1

Introduction to Chemistry Class-6 Dalal Simplified ICSE Chemistry Solutions Chapter-1 Dr Viraf J Dalal Middle School Allied Publishers Solutions. Chapter-1. We Provide Step by Step Solutions of Exercise/Lesson -1  Questions and Answers of Dr Viraf J Dalal Middle School Chemistry Allied Publishers. Visit official Website CISCE for detail information about ICSE Board Class-6.

Introduction to Chemistry Class-6 Dalal Simplified ICSE Chemistry Solutions Chapter-1

Board	ICSE
Class	6th
Subject	Chemistry
Book Name	Dalal New Simplified
Chapter-1	Introduction to Chemistry
Unit-1	Introduction to Chemistry
Topic	Solution of exercise questions
Session	2023-24

Exercise-1

Introduction to Chemistry Class-6 Dalal Simplified ICSE Chemistry Solutions Chapter-1

Question: 1. State what is Science & give the basic bifurcation of Science with reasons.

Answer: Science is the subject which includes the study of various experiments performed by a scientist with all observations recorded and inferences concluded.

Bifurcation: Science is bifurcated into three main branches Physics, Chemistry, and Biology which make the study of each branch simple and more focused.

Question: 2. Give the basic difference between Inorganic Chemistry & Organic Chemistry.

Answer: Organic chemistry:

• Organic chemistry is the discipline of chemistry that deals with the scientific study of organic substances (compounds that contain covalently bonded carbon atoms).
• Organic chemistry is concerned with the structure and chemical composition of organic substances, as well as their physical and chemical properties and chemical reactions.
• For example, compounds include hydrocarbons e.g., Methane (CH4).

Inorganic Chemistry:

• The term “organic” refers to compounds that have carbon atoms in them.
• Thus, ‘Inorganic Chemistry’ is the discipline of chemistry concerned with the study of substances that do not include carbon-hydrogen atoms. It is the opposite of Organic Chemistry.
• Metals, salts, chemical compounds, and other such things that do not contain carbon-hydrogen bonding are examples.

Question: 3. State the functions of the following basic glass apparatus.

Question: (a) Glass test tube

Answer: Glass test tube: It is used for heating chemicals and studying reactions in chemicals solution.

Question: (b) Hard glass boiling tube.

Answer: Hard glass boiling tube: t is resistance to chemicals and used for special purposes. It is made of pyrex.

Question: (c) Beaker

Answer: Beaker: It is used for holding pouring and mixing solutions.

Question: (d) Round bottom flask.

Answer: Round bottom flask: In preparation of gases, Where heating is required. Since the flask is rounded bottomed, heat is uniformly distributed throughout on heating.

Question: (e) Retort

Answer: Retort: For carrying out distillation experiments which include distillation of acids.

Question: 4. State why a round bottom flask is preferred to a flat bottom flask – during preparation of gases in the laboratory.

Answer: Round bottom flask is preferred to flat bottom flask because in round bottom flask heat is uniformly distributed on heating.

Question: 5. State the function of –

Question: (a) The wooden handle at the end of the test tube holder.

Answer: (a) The wooden handle at the end of test tube being a poor conductor of heat, makes holding the test tube holder easy.

Question: (b) The asbestos fixed at the center of the wire gauze.

Answer: (b) The asbestos fixed at the centre of the wire gauze initiates even distribution of heat to the bottom of the apparatus. It also prevents glass apparatus from cracking.

Question: (c) The clamp mounted on the rod of a retort stand.

Answer: (c) The clamp mounted on the rod of a retort stand helps in holding the apparatus and adjusting its level upwards or downwards.

Question: (d) The air regulator in a bunsen burner.

Answer: (d) The air regulator has holes and is used for regulating the flame.

Question: (e) The tap at the base of a burette.

Answer: (e) The tap at the base of the burette helps in removing the measured liquid drop wise.

Question: 6. State the method used for collecting the following gases –

Question: (a) Oxygen – a gas slightly soluble in water.

Answer: The method used for collecting oxygen gas is downward displacement of water. In this method, the gas jar is filled with water and inverted over the beehive shelf, so that the water is displaced downwards and oxygen is collected upwards.

Question: (b) Ammonia – a gas highly soluble in water and lighter than air.

Answer: The method used for collecting ammonia gas is downward displacement of air. This method is used for gases like ammonia which is soluble in water and lighter than air.

Question: (c) Sulphur dioxide – a gas highly soluble in water and heavier than air.

Answer: The method used for collecting SO2​ is upward displacement of air. This method is used for gases like SO2​ which is soluble in water and heavier than air.

Question: 7. Explain in brief the importance of Chemistry in agriculture & production of various products.

Answer: Importance of Chemistry: In agriculture end products and as follows:
1) Agriculture
a) Fertilizers-A substance to improve fertility and supply of nutrients to plant and is essential for growth.
Examples:
1) Ammonium nitrate-widely used as a fertilizer.
2) Urea-an important source of nitrogen [non-explosive and solid in nature]
3) Phosphatic fertilizer-super phosphates
About 90% of fertilizers are in the solid form.
Liquid fertilizers comprise-aqueous solutions of ammonia or ammonium nitrate.
b) Pesticides:
1) Chemicals added to the soil, to kill pests. They include-Herbicides; insecticides, termiticides etc.
2) Pesticides protect the plants from-weeds, fungi and insects.
3) About 30% of crops are destroyed by agricultural pests.
a) Herbicides-Rill or inhibit growth of-unwanted plants.
b) Insecticides-Destroy insects, which harm or destroy plants.
Pesticides may come in contact with other living thing organisms and disrupt the balance of the eco-system.

2) Products-
Knowledge of chemistry has initiated production of -different products
1) Food-Refined oils, butter, cheese, etc. are obtained through chemical reactions.
2) Construction-Mortar, cement, glass ,etc. are various chemical compounds.
3) Clothing-Natural fabrics such as silk are made through chemical reactions.
4) Household-Cooking gas which is liquefied petroleum gas or LPG, food preservatives ,specific utensils and electronic items, all involve use of chemistry.
5) Daily usage-Paints, dyes, perfumes, paper, ink, etc. involve chemical reactions.
6) Industrial-Metals and alloys [mixture of metals] which find application in innumerable machines and metallic structures like automobiles, involve chemistry.
7) Petroleum-Petrol, Kerosene and diesel oil are products-obtained from petroleum.

Question: 8. ‘Alchemists are older words for chemists’. Discuss the statement in brief.

Answer: Alchemy and alchemists are older words for Chemistry and chemists where-alchemists transformed or created substances through a seemingly -magical process. An alchemists Nicolas flame claimed to transform metals into gold.

Question: 9. In the medieval ages – Philosopher’ stone was connected with all transformations. Explain.

Answer: In the medieval ages to the 17th Century to so-called philosopher’s stone-held priority and alchemists were successful to a certain extent, in the development of processes, which helped later chemists to extract metals and develop-path-breaking avenues in Chemistry. The scientific process involving modern chemistry started proving paths and chemistry regains its rightful position.
The Scientific Process involving Modern Chemistry started paving paths and chemistry regains its rightful position.

Question: 10. State the contributions of a

Question: (a) Dimitri Mendeleev

Answer: He formulated the – Periodic Table of elements.  1. He systematically arranged the dozens of known element by atomic weights and could even predict the properties of the still unknown elements.  2. He devised the Periodic Table he was best known for his discovery of the – Periodic Law.

Question: (b) Antoine Lavoisier

Answer: He recognised and named oxygen in 1778 & later – hydrogen in 1783.  2. He also wrote the first extensive list of elements and helped to reform chemical nomenclature.  3. In 1774, he turned his attention to the phenomenon of combustion with his famous experiment, in which he heated pure mercury in a swan necked retort, leading to the discovery of oxygen.

Question: (c) John Dalton-towards the development of Chemistry.

Answer: He compiled his theory in 1803 known as Dalton’s atomic theory.  2. The main postulates of Dalton’s atomic theory are that “Matter consists of particles called atoms, which are indivisible and cannot be created or destroyed.”  3. The theory was later contradicted in certain aspects by the Modem atomic theory.

Question: 11. Differentiate between the terms – food preservatives & food processing with appropriate examples.

Answer: Food preservatives are substances or chemicals added to food or beverages to:

1) Prevent decomposition by bacteria or microbes.

2) Reduce the risk of foodborne infections.

Question: 12. Explain the term ‘cosmetics’ & ‘talc’. Name a few main ingredients in cosmetics & the role they play.

Answer: Cosmetics are mixtures of chemical compounds from natural sources or from synthetic sources.
Cosmetics-enhance or alter the appearance or fragrance of an individual. Some sources of compounds used in cosmetics include-modified natural oils and fats. processed minerals e.g. zinc oxide, iron oxide and talc.
Talc:
1) Talcum powder is made from talc-a mineral made up of -hydrated magnesium silicate, (contains elements -magnesium silicon, oxygen).
2) In its natural form-talc contains asbestos-which is removed from consumer products.
3) Talc-absorbs moisture, cuts down on friction, keeps skin dry and prevents rashes.

Question: 13. Differentiate between – natural fibers & synthetic fibers. State what is – Terylene. State some of its characteristic properties which make it suitable for commercial use.

Answer: Natural fibers-such as cotton and wool which were directly converted into clothing material.
Synthetic fibers-such as terylene, nylon and rayon are used in expensive clothing: carpets etc.
Terylene: It is a synthetic polyester fibre on fabric formed generally, by-addition of polyester to natural fibre-cotton.
The combination makes the fabric, easy to clean and crease resistant.
2) Properties-It is a strong fabric
a) elastic in nature,resistant to friction
b) suffers little loss in strength,
c) crease resistant
d) easily washable and dries quickly.
3) Uses-
a) in fashion garment fabrics
b) in nonwoven carpets, rain coats, sails
c) in making of nets, ropes, hoses etc.

Question: 14. Explain how medicines are a boon to mankind. State the positive & negative effects of medicines like aspirin & paracetamol.

Answer: Medicines are natural or synthetic substances which when taken in a living body, affects its functioning, and treats or prevents a disease.
Aspirin Positive effect:
1) It is a medicine to treat pain, fever and inflammation.
2) Aspirin given shortly after a heart attack, may decrease risk of death.
3) As long term use it may reduce, blood clots in people who are at a high risk.
Aspirin Negative effect:
1) It is generally not recommended in children with infections
2) Its side effects may include upset stomach, stomach ulcers etc.
Paracetamol Positive effect:
1) It is a medicine to treat mild to moderate pain and fever.
2) It may also be used in low back pain, headaches and for dental use.
Paracetamol Negative effect:
1) It may be sold in combination with cold medications.
2) It is safe at recommended doses, but too high a dose may result in liver problems.

Question: 15. Give a comparative difference between – soaps & detergents. Give a reason why detergents have an advantage over soap.

Answer: Soaps are substances used with water, for cleaning and washing and are made from a compound of vegetable oils or animal fats along, with sodium or potassium hydroxide Whereas.
Detergents are synthetic water soluble cleaning agents that unlike soap (which are prepared from vegetable oils or fats) are prepared from petroleum products along with sodium or potassium hydroxide.
Detergents have an advantages over ordinary soap:
1) Hard water is one which does not lather with soap, while soft water lathers easily.
2) Ordinary soap when rubbed in water are removed as scum.
3) Synthetic detergents do not form scum and lather even in hard water.

Question: 16. State what are – ‘stain removals’. Name three important stain removers & give their prime functions.

Answer: Stain removals it is the process of removing a mark or a stain left by one substance on a specific fabric. Most stains are removed by dissolving with solvent.
Examples –

Substance	Stain
Lemon juice	contains citric acid and is used for removing stains from fabrics.
Hydrogen peroxide	a mild bleaching agent also effective in removing stains.
Glycerin	it softens stains on wool

 

– : End of Introduction to Chemistry Class-6 Dalal Simplified Solutions :–

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