9th Chemistry Chapter No 1 Very Very Important Short Question 9th Class. ...
9th Chemistry Chapter No 1
Very Very Important Short Question 9th Class.
Q1: What is a scientific method?
Ans.: A systematic approach used
in scientific study is called as scientific method.
Q2: Define chemistry?
Ans.: “The branch of science that
deals with the composition, structure, properties and reaction of matter is
called as chemistry.”
Chemistry is the study of matter
and its interaction with other matter and with energy. Chemistry is an
experimental science.
Q3:
Define physical chemistry and its scope?
Ans.: “The branch of chemistry
that deals with the relationship between the composition and physical
properties of matter along with the change in them is called physical
chemistry”.
Scope
It deals with the structure of
atom or formation of molecule, behavior of gases, liquid, and solid and the
effect of temperature or radiation on the matter.
Q4: Define the organic chemistry and its scope?
Ans.: “The branch of the
chemistry that deals with the study of covalent compound of carbon and hydrogen
and their derivative is called organic chemistry.”
Scope
This branch covers petroleum,
petrochemicals and pharmaceutical industries.
Q5: Define / states the inorganic chemistry and its scope?
Ans.: “The branch of the
chemistry that deals with the study of all elements and their compounds except
hydrocarbons and their derivatives”.
Scope
It deals with the chemical
industry such as glass, cement, ceramics and metallurgy.
Q6: Define biochemistry and its scope?
Ans.: “The branch of the
chemistry in which we study the structure, composition, and chemical reaction
of bio molecules is called biochemistry”.
Scope
It is chemistry of the life. It
deals with the chemical processes taking place in the living organism. It
applies in the field of medicine, food science and agriculture.
Q7: Define industrial chemistry?
Ans.: “The branch of the
chemistry that deals with the manufacturing of chemical compounds on large
scales is called industrial chemistry”.
This branch deals with the
manufacturing of the basic chemical such as oxygen, chlorine, ammonia, caustic
soda, nitric acid and sulfuric acid.
Q8: Define Analytical chemistry and its scope?
Ans.: the branch of chemistry
that deals with separation and analysis of a sample to identify its components
and composition of substance is called analytical chemistry.
Scope
This branch covers food, water,
environmental and clinical analysis
Q9: define nuclear chemistry and its scope?
Ans.: The branch of chemistry
which deal with radioactivity, nuclear processes and properties is called
nuclear chemistry.
Scope
It is applied in medical
treatment, preservation of food and generation of electric power.
Q10: Environmental chemistry and
its scope?
Ans.: The branch of the chemistry
in which we study the component of the environment and the effect of human
activities on the environment is called as environmental chemistry.
Scope
This branch is related to other
branches of science such as biology, geology, soil, and water etc.
Q11: What is matter?
Ans.: Anything that has mass and occupies space is
called matter.
Matter has three states: solid,
liquid, or gas.
All matter is composed of matter.
Q12: Difference between homo atomic
and hetero atomic molecule?
Homo Atomic Molecule:
“A molecule of an element
containing same type of atom is called a home atomic molecule”.
Example:
H2, N2, O2,
P4
Heteroatomic Molecule:
A
Molecule of a compound containing different kinds of atom is called a
hetero atomic molecule.
Example:
Water (H2O), carbon
dioxide (CO2) ammonia (NH3)
Q13: Find the number of moles in
84g carbon?
Mass of carbon =?
Atomic mass of carbon =12.0g/mole
Formula:
No of moles of carbon = mass of
carbon/At. Mass of carbon
=
84/12.0
=7
moles.
Q14: write the difference between
the atomic number and mass number?
Ans.: Atomic number Z:
The number of protons present in
the nucleus of an atom of the element is called atomic number of an element.
Atomic number = number of proton
Example;
Hydrogen has one proton so atomic
number of hydrogen is 1 similarly atomic number of carbon is 6
Mass number /Atomic mass A:
The sum of the proton and neutron
present in an atom is called as mass number.
Mass number = Number of proton +
number of neutron
Example:
Mass number of hydrogen= 1+0=1 because
hydrogen has no neutron.
Q15: Define molecular Ion and
write its example?
Ans.: A molecular species having
a positive charge on it is called a molecular ion.
Example:
Nitrogen molecule cat ion, N2+, Hydrogen molecule cat ion, H2+
Q16. Differentiate between organic and inorganic
Chemistry?
Ans. Organic Chemistry:
The branch of chemistry in
which we study the covalent compounds of carbon and hydrogen and their
derivatives is called organic chemistry.
Inorganic Chemistry
The branch of the chemistry that deals with the study of all
elements and their compounds except hydrocarbons and their derivatives.
Q17. What is the relative atomic mass?
The average mass of an atom of an element compared with an atom of
carbon-12 isotope is called relative atomic mass of an element.
Q18. Define diatomic molecule and give example.
Ans. A molecule consisting of two atoms is called a
diatomic molecule.
Example: Hydrogen (H2), Nitrogen (N2),
Oxygen (O2).
Q19. Differentiate between homoatomic molecule and
heteroatomic molecule?
Ans. Homoatomic molecule:
The molecule that contains same type of atoms is known as homoatomic
molecule. Such as O2, O3, H2.
Heteroatomic molecule:
The molecule that contains different type of atoms is known as
heteroatomic molecule. Such as H2O, CO2
Q20. Define triatomic molecule and polyatomic
molecule.
Ans. Triatomic molecule:
The molecule which contains three atoms is known as triatomic molecule,
such as H2O, CO2
Polyatomic molecule:
The molecule which
contains four or more than four atoms is known as polyatomic molecule such as H2O2,
C6H12O6
Q21. Define formula mass? Give example.
Ans. Formula mass:
Formula mass is the sum of atomic masses of all atoms in formula unit of
substance, such as formula mass calcium chloride is 74.5
Q22. How many molecules in 9 gram of water?
Ans. Given data:
Known mass = 9
Molar mass of H2O=18
Solution:
Moles =9/18 = 0.5 g\mol
Molecules =A.N ×0.5=6.02×1023×0.5
Q23. Define element? Give example.
Ans. A pure substance composed of only one kind of
atom having the same atomic number is called element. Such as Na, Ag, Cu, Fe.
Q24. Differentiate between chemical properties and
physical properties?
Ans. Chemical properties:
A
chemical property depends upon composition of a substance. Such as rusting of
iron, burning of coal and gasoline in air
Physical properties:
Physical properties are those which are associated with physical state
of matter. Such as Color, taste, hardness
Q25. Write valency of Barium, Nitrogen, Sodium and
Sulfur?
Ans. Barium Ba : +2 Nitrogen N
: -3
Sodium Na : +1 Sulfur S
:-2
Q26. Define mole. Give examples.
Ans. The
amount of a substance that contains 6.02×1023particles molecules or
formula units is called a mole. Such as 1 mole of C = atomic mass of C =12.0g
Q27. Write the molecular mass of (HNO3)?
Ans. H=1,
N=14, O=16
Molecular mass=1+14+3(16)
=79
Q28. Define relative atomic mass.
Ans. Relative atomic mass of an element is the
average mass of an atom of an element as compared to 1/12Th of an
atom of carbon -12 isotopes.
Q29. Write the formula mass of Na2So4.
Ans. Mass of Na= 23 Mass of S=32 Mass of O=16
Total
formula mass = 2(23) +32+4(16) = 142g
Q30. Differentiate between Molecule and Molecular
ion.
Ans. Molecule
·
Molecule is the smallest particle of an element or compound.
·
It has stable units.
·
It has net charge on it.
·
It cannot exist independently.
·
It is formed by the combination of ions.
·
It has negative or positive charges on it.
·
It can or cannot exist independently.
Q31. Define free radical. Give an example.
Ans. An atom
or group of atoms having one unpaired electron is called a free radical. Such
as Chlorine free radical Cl˚˚
Q32. Differentiate between ions and free radical?
Ans.
Ions
|
Free radical
|
These are atoms or group of atoms having charge.
|
These are
atoms or group of atoms having odd electrons.
|
They exist
in solution or in crystal lattice.
|
They can
exist in solution as well as in air.
|
Their
formation is not affected by presence of light.
|
They may
form in the presence of light.
|
Q33. Define cation?
Ans. An atom or group of atoms having negative
charge on it is called cation.
Example:
Na2,8,1→Na2,8+ē
Q34. Define symbol.
Ans. An abbreviation used for the name of element is
called symbol.
Example:
Name
symbol
Boron B
Carbon C
Fluorine F
