Class-6 Dalal Introduction to Chemistry ICSE New Simplified
Class-6 Dalal Introduction to Chemistry ICSE New Simplified Solutions Dr Viraf J Dalal Middle School Allied Publishers Solutions. Chapter-1. We Provide Step by Step Solutions of Exercise/Lesson -1 Elements Compound and Mixtures with Objective Type Questions, Fill in the blanks and Give reason , Match the following of Dr Viraf J Dalal Middle School Chemistry Allied Publishers. Visit official Website CISCE for detail information about ICSE Board Class-6.
Class-6 Dalal Introduction to Chemistry ICSE New Simplified Solutions Chapter-1
State what is Science and give the basic bifurcation of Science with reasons.
Branch of study which includes the study of various experiments performed by a scientist with all observations recorded and inferences concluded is known as Science
Science is bifurcated into three main category—
Give the basic difference between Inorganic Chemistry and Organic Chemistry.
|Elements||include||Sulphur, Phosphorus, Sodium, Potassium|
|Gases||include||SO2, CO2, N|
|Acids||include||HCl, H2SO4, HNO3|
Organic chemistry includes study of specific carbon compounds built up mainly of carbon and hydrogen.
State the functions of the following basic glass apparatus.
(a) Glass test tube
(b) Hard glass boiling tube
(d) Round bottom flask
(a) Glass test tube : test tube is used for heating chemicals and studying reactions in chemicals solution.
(b) Hard glass, boiling tube : Hard glass, boiling tube is resistant to chemicals and used for special purposes. It is made of pyrex.
(c) Beaker : Beaker is used for holding pouring and mixing solutions.
(d) Round bottom flask : round bottomed is used In preparation of gases, where heating is required. Since, heat is uniformly distributed throughout on heating.
(e) Retort : It is used for carrying out distillation experiments which include distillation of acids.
State why a round bottom flask is preferred to a flat bottom flask – during preparation of gases in the laboratory.
It is preferred to flat bottom flask because in round bottom flask since heat is uniformly distributed in it
State the function of –
(a) The wooden handle at the end of the test tube holder.
(b) The asbestos fixed at the centre of the wire gauze.
(c) The clamp mounted on the rod of a retort stand.
(d) The air regulator in a Bunsen burner.
(e) The tap at the base of a burette.
(a) being a poor conductor of heat The wooden handle at the end of test tube , makes holding the test tube holding easy.
(b) An 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.
(c) for holding the apparatus and adjusting its level upwards or downwards.
(d) It is used for regulating the flame as air regulator has holes
(e) helps in removing the measured liquid drop wise.
State the method used for collecting the following gases –
(a) Oxygen – a gas slightly soluble in water.
(b) Ammonia – a gas highly soluble in water and lighter than air.
(c) Sulphur dioxide – a gas highly soluble in water and heavier than air.
(a) downward displacement of water.
(b) downward displacement of air.
(c) upward displacement of air.
Explain in brief the importance of Chemistry in agriculture and production of various products.
Importance of Chemistry
Fertilizers – A substance to improve fertility and supply of nutrients to plant and is essential for growth. EX- Ammonium nitrate – Urea – Phosphatic fertilizer – super phosphates.
Pesticides- Chemicals added to the soil, to kill pests. They include – Herbicides; insecticides; termiticides etc.
Food – oils, butter, cheese,
Construction – Mortar, cement, glass,
Clothing – silk Polyster nylon Rayon
Household – liquefied petroleum gas or LPG, food preservatives, specific utensils and electronic goods
Daily usage – Paints, dyes, perfumes, paper, ink
Industrial – alloys machines and automobiles,
Petrolium – Petrol, kerosene diesel
‘Alchemists are older words for Chemists’. Discuss the statement in brief.
Alchemists created substances through a seemingly magical process. Alchemy and alchemists are old terms used for chemistry and chemists. An alchemist named Nicolas Flamel claimed to transform metals into gold.
In the medieval ages – philosopher’s stone was connected with all transformations. Explain.
During the medieval ages, in the 17th century, the so called philosopher’s stone held priority and the alchemists were successful to a certain extent that in the developmental process. It is said that later, it helped chemists to extract metals and develop a new approach in chemistry. Processes that involved modern chemistry started proving paths and chemistry regained its rightful position
State the contributions of
(a) Dimitri Mendeleev
(b) Antoine Lavoisier
(c) John Dalton – towards the development of Chemistry.
(a) Dimitri Mendeleev :
- Formulated the periodic table of elements
- Mendeleev arranged the dozens of known elements by atomic weights and also predicted the properties of certain unknown elements.
- He also discovered the periodic law.
(b) Antoine Lavoisier :
- In 1778 he recognised and named oxygen.
- In 1783 he recognised and named hydrogen.
- He wrote the first extensive list of elements and helped to reform chemical nomenclature.
- In 1774, he focused on the phenomenon of combustion. He conducted an experiment in which he heated pure mercury in a swan necked retort, leading to the discovery of oxygen.
(c) John Dalton :
- In 1803, he compiled his theory named as Dalton’s atomic theory.
- In his theory he discussed Matter that consists of particles called atoms which are invisible and cannot be created or destroyed. Later, this theory was contradicted in certain aspects by “Modern Atomic theory”
Differentiate between the terms – food preservatives and food processing with appropriate examples.
Food preservatives – A Food preservatives (Benzoic acid Nitrates Sulphur compounds ) are chemicals that are added to food for following purpose
- Prevent decomposition by bacteria or microbes.
- Reduce risk of food infections.
- Preserve nutritional quality of food.
Food processing :- Food processing is the transformation of agricultural products into food or one form of food into other forms
Explain the term ‘cosmetics’ & ‘talc’. Name a few main ingredients in cosmetics the role they play.
Cosmetics are mixtures of chemical compounds from natural sources or from synthetic sources. Cosmetics enhance or alter the appearance or fragrance of an individual.
Modified natural oils and fats, processed minerals like zinc oxide, iron and talc are a few examples of sources of compounds that are used in cosmetics.
Talc is a mineral made up of hydrated magnesium silicate. Talcum powder is made from talc.
Talc contains asbestos in its natural form, which is removed from consumer products. It absorbs moisture, cuts down on friction and keeps skin dry.
Differentiate between – natural fibres & synthetic fibres. State what is – Terylene. State some of its characteristic properties which make it suitable for commercial use.
Natural fibres – Hair , cotton and wool
Synthetic fibres – terylene, nylon and rayon
Terylene – a synthetic polyester fibre or fabric formed generally, by – addition of polyester to natural fibre – cotton. The combination makes the fabric, easy to clean and crease resistant.,
Properties of synthetic fibres.
(a) elastic in nature, resistant to friction,
(b) suffers little loss in strength,
(c) Long life and crease resistant,
(d) easily washable and dries quickly.
Uses of synthetic fibres.
(a) used in garment industry
(b) Fit in nonwoven carpets, rain coats, sails
(c) Preparing of nets, ropes, hoses etc.
Explain how medicines are a boon to mankind. State the positive & negative effects of medicines like aspirin and paracetamol.
A substances which when taken by a living body, act as curative or preventative a disease.is called Medicines which may be natural or synthetic
Positive effect of Aspirin :
- Aspirin is used to treat pain, fever and inflammation.
- It is given shortly after a heart attack, may decrease risk of death.
- it may reduce chance of blood clots in people who are at a high risk.
Negative effect of Aspirin :
- Aspirin is generally not recommended in children with infections.
- Its side effects may include upset stomach, stomach ulcers etc.
Positive effect of Paracetamol :
- Paracetamol is a medicine to treat mild to moderate pain and fever.
- It may also be used in low back pain, headaches and for dental use.
Negative effect of Paracetamol ::
- Paracetamol may be sold in combination with cold medications.
- It is safe at recommended doses, but too high a dose may result in liver problems.
Give a comparative difference between – soaps and detergents. Give a reason why detergents have an advantage over soap.
Soaps :- The 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 are called Soap
Detergents:- substances which is synthetic in nature and water soluble cleaning agents that are prepared from petroleum products are called Detergents.
Advantage of Detergents over soap
- In Hard water Detergents produce leather while soap not
- Ordinary soap when rubbed in hard water is wasted and lather forms only after all the insoluble salts in hard water are removed as scum.
- Synthetic detergents do not form scum and lather even in hard water.
State what are – ‘stain removals’. Name three important stain removers & give their prime functions.
Stain removals :- process of removing a mark or a stain left with a chemical is called Stain removals
Examples – Hydrogen peroxide, Glycerine , Lemon juice
Objective Type Questions
Class-6 Dalal Introduction to Chemistry ICSE New Simplified Solutions Chapter-1
Select the correct name from the choice A, B or C in each case.
- The branch of science which deals with the different forms of energy r.g. Light and sound
- The branch of chemistry which includes study of specific carbon compounds built up of mainly carbon and hydrogen
(A) Inorganic Chemistry
(B) Physical Chemistry
(C) Organic Chemistry
- The scientist who formulated the periodic table
(A) John Dalton
(B) Daniel Rutherfold
(C) Demitri Mendeleev
- Predecessors to the modern Chemist who created the philosopher’s stone
- A synthetic fibre used in clothing
- A medicine to treat pain, fever & inflammation
- A water soluble cleaning agent – not inactivated by hard water
- A substance which absorbs moisture and keeps the skin dry and free from rashes
- A chemical used as a preservative for jams, pickles etc
(A) Titanium dioxide
(C) Benzoic acid
- A substance which dissolves grease & oil and is preferred as a – drain cleaner
(B) Sodium Hydroxide
(C) Hydrogen peroxide
- (B) Physics
- (C) Organic Chemistry
- (C) Demitri Mendeleev
- (B) Alchemists
- (C) Terylene
- (B) Aspirin
- (B) Detergent
- (A) Talc
- (C) Benzoic acid
- (B) Sodium Hydroxide
Match the apparatus A to J shown below with their correct names 1 to 10 given below :
1. Delivery Tube
3. Wire gauze
4. Bee-hive shelf
5. Thistle funnel
6. Flat bottom flask
7. Test tube stand
10. Conical flask
- Delivery Tube — G
- Pipette — H
- Wire gauze — B
- Bee-hive shelf — D
- Thistle funnel — J
- Flat bottom flask — I
- Test tube stand — A
- Burette — E
- Retort — F
- Conical flask — C
Select the correct apparatus from A, B or C for each of the functions of the apparatus given.
For gas preparations where heating is required.
(A) Flat bottom flask
(C) Round bottom flask
For holding washed test tubes.
(A) Test tube holder
(B) Test tube stand
(C) Retort stand
A glass apparatus resistant to chemicals, made of pyrex and used for heating specific liquids.
(C) Boiling Tube
A metallic apparatus which supports the wire gauze.
(A) A Tripod stand
(B) Retort stand
(C) Test tube stand
A long glass apparatus closed at one end used for collecting gases.
(A) Measuring cylinder
(B) Gas jar
(C) Beehive shelf
A glass apparatus which measures liquid by sucking the liquid at one end upto the marked level and later pouring it out.
(B) Measuring cylinder
A long glass tube with a broad inlet at the top, which allows entry of the reactants into the round bottom flask, during laboratory preparations of gases.
(A) Thistle funnel
(B) Delivery tube
A clay vessel kept in a trough of water during collection of a gas by downward displacement of water.
(B) Beehive shelf
A modern apparatus with an air regulator, used for heating purposes.
(A) Spirit lamp
(B) Bunsen burner
(C) Electric stove
A rectangular mesh with an asbestos at its centre, kept for initiating even distribution of heat to the bottom of the apparatus.
(A) Tripod stand
(B) Wire gauze
(C) Retort stand
- (C) Round bottom flask
- (B) Test tube stand
- (C) Boiling Tube
- (A) A Tripod stand
- (B) Gas jar
- (C) Pipette
- (A) Thistle funnel
- (B) Beehive shelf
- (B) Bunsen burner
- (B) Wire gauze
Give reasons for the following :
- Alchemy was considered a pseudoscience.
- Preservatives are added to food or beverages .
- Titanium dioxide is an important ingredient in cosmetics.
- Aspirin is one of the most widely used medication – globally.
- Ordinary soap is wasted in hard water.
- A philosopher’s stone is not exactly a stone.
- Food processing is an important procedure for obatining marketable food products .
- Cosmetics may contain preservatives , as one of their ingredients.
- Polyester is added to natural fibre cotton, to give terylene.
- All medicines must be taken under proper doctors supervision and in the correct dose.
- Towards the end of the 17th century the scientific processes involving modern chemistry started paving paths and alchemy today is considered a pseudoscience and chemistry regains its rightful position as a serious scientific field.
- Preservatives are added to food or beverages because of Prevent decomposition by bacteria or microbes, Reduce risk of foodborne infections, Preserve nutritional quality of food.
- It is a natural pigment powder which provides a base for mineral makeup. It provides mild sun protection and as a pigment gives a white colouration to coloured ingredients.
- Aspirin is one of the most widely used medication- because It is a medicine to treat pain, fever & inflammation., Aspirin given shortly after a heart attack, may decrease the risk of death.,As long term use it may reduce blood clots in people who are at a high risk.
- Hard water is one which does not lather with soap and thus ordinary soap is wasted in hard water.
- Philosopher’s stone is a legendary substance, capable of turning inexpensive metals like lead or mercury into- gold and silver.
- Food processing- involves physical or chemical processes, to transform or change the raw ingredients in food into easy usable forms of food available in markets. Raw materials- in food to marketable food products.
- They extend the shelf life of a cosmetic and may prevent the growth of microorganisms.
- Polyester is added to natural fibre cotton, to give terylene because this combination makes the fabric easy to clean and create resistant.
- Some medicines have side effects as aspirin not taken in proper dose may cause stomach ulcers similarly paracetamol if taken in high dose may cause liver problems. Thus all medicines must be taken under proper doctors supervision and in the correct dose.