Selina Concise Class 6 Chemistry Solution Chapter No. 1- ‘Introduction To Chemistry’ For ICSE Board Students.
(1.) GIVE TWO EXAMPLES FOR EACH OF THE FOLLOWING SUBSTANCES:-
a) FOOD PRESERVATIONS:- 1. Sodium benzoate 2. Salicyclic acid
b) FUEL:- 1.Diesel 2. PETROL Kerosene
C) FUNGICIDES:- 1. Sulphur Bordeaux mixture..
d) MEDICINES:- 1. Penicilin. Aspirin
e) BUILDING MATERIALS:- Cement 2. Steel
f) CHEMICAL WAR WEAPONS:- TNT 2. Laughing gas. 3.RDX
(2.) Give Short Answers Solution:
a) WHAT IS SCIENCE?
ANS:- Science is the systametic, ongoing effort by human beings to study, understand and utilize nature for meaningful purposes. This understanding is slowly developed by the careful observations and experiment.
b) WHAT IS CHEMISTRY?
ANS:- The branch of science that deals with the study of the composition and the physical and chemical properties of various forms of matter is called chemistry.
c) WHAT IS FUELS?
ANS:- Fuels are the substance which on combustion produce large amount of heat energy.
d) HOW IS CHEMISTRY HELPFUL IN IMPROVING THE HEALTH OF HUMAN BEINGS?
ANS:- Chemistry is helpful in improving the health of human beings by providing antibiotics,pain killers, etc. It finds applications in day to day life as well as an industries. Chemicals from simple to complex are used in medicines, cosmetics, agriculture, cleaning agents etc. Many useful substance is produced through chemical process. They help us in turn of improving our National economy.
e) WHAT IS ALCHEMY?
ANS:- The word Alchemy has its origin in a greek word ‘khemia’ means “art of transmuting metals”. It was partly based on experimentations and partly on spiritual discipline.
f) WHAT KIND OF EXPERIMENTS DID ALCHEMISTS DO?
ANS:- Alchemists considered to be early chemists. They used all general techniques of chemistry in healing humans. Their contribution proved valuable to the society and in the advancement of civilization. They had contributed t an incredible number of future uses of chemicals,metals,paints,cosmetic,medicines etc.
g) WHAT IS PHILOSOPHERS STONE?
ANS:- The goal of alchemy was to find a mythical and magical substance called “philosophers stone” not a literal stone but wax,liquid or powder with magical powder, which on heating with a base , iron,copper metals would turn into gold, the purest from of matter which would bring wealth, health and immortality.
h) WHAT IS THE MAIN DIFFERENCE BETWEEN ALCHEMY AND CHEMISTRY?
ANS:- Alchemy was both scientific and spiritual. Alchemists never separated them. It also lacked a common language for its concepts and process i.e there was no standardlized scientific practice.
Chemistry was completely separated from ancient traditional alchemy. Still modern chemistry in general ownes a great deal to alchemy. Alloys are formed by mixing metals with other metals and substances.
(I) NAME THE CHEMICALS WHICH HELP IN INCREASING FOOD PRODUCTION?
ANS:- The chemicals are fertilizers like sodium nitrate, ammonium phosphate etc. and Pesticides like parathion, malathion which are used to kill pests. Insecticides like D.D.T , B.H.C etc.
j) NAME SIX SUCH PRODUCTS WHICH WE USE DAILY?
ANS:- Six products name are soap, paints, tooth-paste, detergents, cooking oil, Plastics, dyes etc
(3) WHAT IS THE CONTRIBUTION OF CHEMISTRY IN THE FOLLOWING FIELD?
a) INDUSTRY:- To improve efficiency and production of metals, paints, paper, plastics, textile, electroplating, cosmatics , fibres etc.
b) CLOTHINGS:- Chemistry is widely used in textile industry which manufactures clothing for us. Clothes guard our body from external environment. Formation of clothing begins with the knowledge of conservation of fibres into fabrics. Fibres can be natural or synthetic. Earlier only natural fibres were known to man such as cotton, jute, silk, wool, etc. which were used to produce dress materials,sarees,bags, sweaters, shawls etc. These fibres are strong , wrinkle resistant and dry quickly. They are used to make towels,bed sheets, bags, carpets, blankets, etc.
c) COSMETICS:- Cosmetics are the products used to clense, protect, of external part of the human bodies. Example-talcum powder, skincare creams, lipsticks, eyes and facial make up, deodorants, lotions, perfumes, bathing oil, baby products, etc. It is possible to convert various incredients into usable cosmetics due to knowledge of chemistry.
d) NATIONAL DEFENCE:- Substances like gunpowder, T.N.T, chemical weapons, laughing gas etc are all products of chemistry which contribute to the national defence.
e) MEDICINES:- Extensive researchers by chemists have led to the discovery of number of medicine drugs. These drugs help in fighting diseases and have thus increased the life span of human beings. Examples:- Aspirin, Paracetamol, tetracycline, antiseptics, and various other medicines used to kill germs and cure diseases and their symptoms.
(4) WHO IS KNOWN AS FATHER OF CHEMISTRY? WHY?
ANS:- Robert William boyle is known as ‘Father of modern chemistry’. He was an anglo irish scientist born in Ireland. He was the first to perform experiments under controlled conditions and publish his researches with elaborate details of procedure, apparatus, and observations. He defined elements, compounds, and mixtures.
(5.) NAME THE SCIENTISTS WHO DISCOVERED THE FOLLOWING:-
a) ATOMS:- John Dalton was a british chemist and physicist. He proved that matter consists of small indivisible called atoms. For this he proposed the atomic theoy which was later on called “ Daltons atomic theory”.
b) OXYGEN:- Joseph Priestly.
c) SAFETY LAMP:- Sir humphry davy.
d) ELEMENTS:- Antoiene Lavosier.