Sindh | Karachi Grade 9th Chemistry Notes Chapter1(Introduction to Chemistry) short and long questions pdf download.
Sindh Board | Karachi 9 Class Chemistry Cha 1 Introduction To Chemistry MCQs
Table of Contents
Formula for water
A: H2o
B: Nacl
C: Hcl
D: all
Answer: A
How many branches are in Chemistry?
A: 8
B: 9
C: 5
D: 10
Answer: B
How many branches in chemistry
A: 10
B: 6
C: 8
D: 12
Answer: C
Sulphuric acid was discovered by
A: Jabir bin hayyan
B: Al razi
C: Al beruni
D: Berzellius
Answer: A
When was oxygen fist discovered?
A: 1772
B: 1775
C: 1773
D: 1776
Answer: A
who arranged the elements in the Periodic table?
A: Rutherford
B: Neil Bohr
C: Jhon Dalton
D: Mendeleev
Answer: D
Golden scriptwriting with iron pyrites was introduced by?
Ibne Sena
Al-Beruni
Al-Razi
Jabir Bin Hayan
A theory, which gives the same results after repeated experiments become a?
Law
Truth
Fact
Hypothesis
The compounds of what are used in toothpaste to prevent the decay of teeth?
Oxides
Halides
Fluorides
Chlorides
The Muslim period extends from:?
- 600\-1600 A.D
- 200-2000 A.D
- 800-1300 A.D
- 100-1000 A.D
Did man start chemical activities by looking at?
- Respiration
- Combustion
- Photosynthesis
- Condensation
Who discovered nitric acid, hydrochloric acid, and sulphuric acid?
- Al-Haitham
- Al-Razi
- Jabir Bin Hayan
- Al-Beruni
Who presented the laws of electrolysis?
- J.Berzelius
- Michael Faraday
- Rutherford
- Neil Bohr
Which one of these was the first to use opium as anesthesia?
- Bu Ali Sina
- Al-Beruni
- Jabir-ibin-Haiyan
- Al RaAzi
Which gas is studied by J-Black.?
- hydrogen chloride
- sulpherdioxide
- carbondioxide
- carbonmonodioxide
Which one of these was the first to use opium as anesthesia?
- Bu Ali Sina
- Al-Beruni
- Jabir-ibin-Haiyan
- Al RaAzi
Which gas is studied by J-Black.?
- hydrogen chloride
- sulpherdioxide
- carbondioxide
- carbonmonodioxide
Scheele discovered ———–.?
- Oxygen
- Fluorine
- Iodine
- chlorine
Which of these branches of chemistry deals with the study of compounds of living organisms.?
- Analytical chemistry
- Environmental chemistry
- Organic chemistry
- Biochemistry
The study of laws and principles governing the combination of atoms and molecules in a chemical reaction is called ———–.?
- Inorganic chemistry
- Industrial chemistry
- Physical chemistry
- Analytical chemistry
Greek philosopher introduced the concept of elements on earth.?
- Six
- Five
- Four
- Three
Which one of these scientists is known as the Father of Chemistry?
- Bu Ali Sina
- Aristotle
- Al-Beruni
- Jabir bin Haiyan
Information acquired through careful observation is known as:?
- Prediction
- Theory
- Facts
- None of them
A theory when repeatedly gives the same results after experimentation and offers a correct explanation of the scientific facts, it then becomes?
- Law
- Principle
- Both a and b
- None of them
Which one of these scientists suggested the symbols of elements?
- Wholer
- Faraday
- Dalton
- Berzelius
Define chemistry and describe its importance.
Answer:
Chemistry:
Chemistry is the branch of science that deals with the properties, composition, and structure of matter. It also deals with the changes and principles governing the changes in the matter.
Importance of Chemistry:
Everything is made of atoms. Many of the changes we observe around us are chemical changes. Chemistry is very important because it helps to know the composition, structure, and changes of matter. Our body is made up of chemical composites, which are a combination of elements including carbon and hydrogen to make proteins and a wide range of biochemical molecules. From small a pin to the atmosphere, everything is made up of elements. Chemistry plays a very important role in our life.
At the micro-level, it controls all the biological functions of humans, animals, and plants. A minor chemical disorder can drastically disrupt the processes vital to life.
At the macro level, chemistry is at work all around us. Preparation of food, manufacturing of clothes, medicine, utensils, building materials, automobiles, energy, power, etc. all have their origin in chemistry. All chemicals play a vital role in the body. Such as glucose is the essential monomer of many polymers that exist in the human body. Glucose plays a very vital role in the functioning of the human body. Many chemical reactions that take place in the body contain glucose.
So chemists need to have an in-depth study of chemical processes and properties to play their role effectively for the betterment of the world in general and humankind in particular.
Write a note on the historical development of chemistry with special mentioning of the contribution of Muslim scientists in the field of chemistry.
Answer:
Muslim scientists brought rich contributions in various branches of sciences and specifically in the field of chemistry. They introduced many scientific methods and experiments. They invented many laboratory equipments such as funnels, beakers, crucibles for melting and fusion, retorts for distillation, balances for weighing, etc. They also discovered many acids, alcohols, and medicines.
The period of alchemists was from 600 to 1600 A.D in the history of chemistry. Jabir Ibne-Haiyan (721-803 A.D) is also known as the father of chemistry. His great work was the invention of experimental methods for the preparation of nitric acid, hydrochloric acid, and white lead.
Another scientist, physician, and philosopher were Al Razi (862-930 A.D). He was the first one who used opium as anesthesia. In 1806, he classified chemical compounds on the basis of their origins of organic and inorganic compounds. His great work was the preparation of ethyl alcohol by the fermentation process.
In the field of chemistry Al-Beruni (973-1048 A.D) determined the densities of different substances.
Ibne-Sina (980-1037 A.D) was famous for his contribution to the field of medicinal chemistry.
These Muslim scientists were more interested in the conversion of metals like lead, copper into gold. Their attempts were not successful but they laid down the foundation of chemistry. Alchemists’ main concern was the production of drugs for the prolonged life. Thus modern knowledge is based on the contribution of these Muslim scientists.
What important role does chemistry play in society?
Chemistry plays a very important role in society. It helps to discover new materials and elements. It deals with the protection of the environment and providing the needs of life. It provides pharmaceutical chemicals that enhance our health and prolong our lives.
The role of chemistry in the prevailing society is of enormous benefits. We are familiar with many chemicals which have become part and parcel of our daily life.
Chlorine has become an important commercial chemical. Today chlorine has turned into the main element for producing more than one thousand chlorine compounds, which are of great importance in the chemical industry, producing Poly Vinyl Chloride (PVC) as plastics for pipes. Other Chlorine compounds are used as bleaching agents, disinfectants, solvents, pesticides, refrigerants, flame retardants, and drugs.
Cholera, typhoid fever, and dysentery are dangerous diseases, transmitted through impure drinking water. All such water-borne diseases are all but eliminated from most of the parts of the world when water supplies are treated with chlorine which kills pathogenic (disease-causing) organisms. Chemistry plays an important role in the modern world. For example, food, synthetic fibers, plastics, medicines, soap, detergents, cosmetics, cement, fertilizers, glass, and explosives are major gifts of chemistry.
What do you mean by the scientific approach in chemistry? How will you differentiate between hypothesis and theory?
Over the years science has developed through a series of discoveries that started off as observed natural phenomena which had to be explained. This was done by using the scientific method in a systematic manner.
i) Observation
Different people observe a phenomenon in different ways. Some of us observe something very critically to extract from it a new point.
Observation is a basic tool to go forth for elaborating a phenomenon but it may vary from person to person according to his own skill of elaboration. Observation of a thing is one of the scientific approaches in chemistry.
ii) Hypothesis
When a phenomenon is observed; a scientist ponders over it and carries out relevant experiments. He sieves through the data and arrives at a possible explanation for the nature of the phenomenon. This explanation; which is still only a trial idea is called a hypothesis. It may or may not undergo a change as a result of further investigations and accumulation of more knowledge or facts.
iii) Theory
The scientist conveys his hypothesis to other workers of the same field for discussion and for further experimentation. When the hypothesis is supported by a large amount of different types of observations and experiments, then it becomes a theory i.e. scientifically acceptable idea or principle to explain a phenomenon. A good theory predicts new facts and unravels new relationship between naturally occurring phenomena.
iv) Scientific Law
A theory which is tested again and again and found to fit the facts and from which valid predictions may be made is then known as scientific law or principle.
What is a scientific law?
A theory that is tested again and again and gives nearness predictions on its approval gives a scientific law.
However, not all hypotheses and theories pass successfully to become scientific laws. Some may sound very convincing and be supported by mathematical calculations but are very difficult to prove experimentally. This is invariably due to the material under investigation or the lack of suitable working equipment. A typical example is Avogadro’s hypothesis which has not been proved conclusively and yet it is accepted as Avogadro’s law.
Science cherishes all forms of ideas and proposals. Even obsolete ideas are kept as a reference. It is said that there is no end to knowledge, so development in science too may have no limits.
Name the different branches of chemistry and define them.Â
There are various branches of chemistry. Here we will discuss some of them.
i) Physical Chemistry:
It is the branch of chemistry that deals with the laws and principles governing the combination of atoms and molecules in chemical reactions.
ii) Organic Chemistry:
It is the branch of chemistry that deals with the carbon compounds with the exception of CO2, CO metal carbonates, bicarbonates and carbides. It is the chemistry of hydrocarbons and their derivatives.
iii) Inorganic Chemistry:
It is the branch of chemistry that deals with the chemistry of elements and their compounds, generally obtained from non-living things. For example, minerals.
iv) Analytical Chemistry:
It is the branch of chemistry that deals with the study of the methods and techniques involved to determine the kind, quality and quantity of various components in a given substance.
v) Biochemistry:
It is the branch of chemistry that deals with the compounds of living organisms. For example, plants, animals and their metabolism in the living body.
vi) Industrial Chemistry:
It is the branch of chemistry that deals with the study of different chemical processes involved in the chemical industries for the manufacturing of synthetic products like glass, cement, paper, soda ash, fertilizers, medicines etc.
vii) Nuclear Chemistry:
It is the branch of chemistry that deals with the study of changes occurring in the nuclei of atoms, accompanied by the emission of invisible radiations.
viii) Environmental Chemistry:
It is the branch of chemistry that deals with the study of the interaction of chemical materials and their effect on the environment.
ix) Polymeric Chemistry:
It is the branch of chemistry that deals with the study of polymerization and the products obtained through the process of polymerization such as plastic, synthetic fiber, paper etc.
