9th Class Chemistry English Medium Chapter 1 Online Short Question Preparations

Preparations for exams is the most stressful part in a student's life and it became tougher when a student has not any particular know-how that how to do preparations for exams and how to get good results. Students who as a beginners in their board exams are mostly very anxious from their tip to toe because they can't feel satisfied with how much they prepared for their board exams, and that's a common problem among all the students of BISE, this issue now finally has been resolved by the hardships of this website ilmkidunya because this website portal give all the BISE students in Pakistan an online preparation method from where a student is easily re-test himself/herself before starting of taking their boards exams.

Chemistry, when a student firstly listens to this subject name they definitely come in stress because the chemistry subject is as difficult as its name indicates it. When a student starts its preparation for exams he/she feel uneasy to learn some subjects chemistry is also one of them because of containing many numerical, balance chemical equations, chemical reactions, and its end products and many other things. To get a full grip and strong command on this entire subject a student is need to understand this subject high logics which is mostly based on its chemical equations, chemical reactions and also the numerical side which if a student is well practiced in solving these things he/she must get the highest grade in his/her board exams because these mathematical base questions give you full marks present in any subject.

Understanding the need for the student the ilmkidunya.com organize the online preparations setup for all the ninth class students according to the syllabus issued from the board of examination. This website provides a platform where the students can easily prepare themselves for all subjects of the ninth class before their exams by explaining each subject in a simple and easy way. This site dividing the chapters in the form of units and each unit is given in the form of the short questions and their appropriate answers, and a timer is also given there because all these setups are produced for the students to prepare themselves according to the board exams pattern. By solving each unit of every subject, a student is easily capable to solve the whole question paper in exams because this website gives a highly emphasize on every topic and provided all the basic and essential requirements according to the demand and needs of the student and the educational board in Pakistan.

This online preparation method is fully free to practice test session for all the students of ninth class and any student can use it after login itself in it. It is too simple to do and too useful for exams preparations.

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9th Class Chemistry Chapter 1 Online Preparation
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Online Short Questions For Chapter 1 "9th Class Chemistry English Medium Chapter 1 Preparation "

Try The Short Questions For 9th Class Chemistry English Medium Chapter 1 Preparation

  • Total Questions10

  • Available Sets86

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Chemistry (New Book) - 9th Class Chemistry English Medium Chapter 1 Preparation

Question # 1

What is difference between polar and non-polar covalent bonds, explain with one example of each?

  • Ans 1:
    Polar Covalent Bonds Non-Polar Covalent Bonds
    If the covalent bond is formed between two different types of atoms then bond pair of electrons will not be attracted equally by the bonded atoms. One of the atoms will attract the bond pair of electrons more strongly than the other one. They form polar covalent bond. For example: H+—F', H+—CI-
  • Ans 2: Non-polar covalent bond :
    If the covalent bond is formed between two similar the shared pair of electrons is attracted by both the atoms equallySuch type of covalent bond is called non-polar covalent bond
  • Ans 3: Example : H2 and Cl2 H-H, Cl-Cl
Submit

Prepare Complete Set Wise Questions For Chapter 1 "9th Class Chemistry English Medium Chapter 1 Preparation "

9th Class Chemistry English Medium Chapter 1 Preparation - Set 1

Question # 1

What is difference between polar and non-polar covalent bonds, explain with one example of each?

  • Ans 1:
    Polar Covalent Bonds Non-Polar Covalent Bonds
    If the covalent bond is formed between two different types of atoms then bond pair of electrons will not be attracted equally by the bonded atoms. One of the atoms will attract the bond pair of electrons more strongly than the other one. They form polar covalent bond. For example: H+—F', H+—CI-
  • Ans 2: Non-polar covalent bond :
    If the covalent bond is formed between two similar the shared pair of electrons is attracted by both the atoms equallySuch type of covalent bond is called non-polar covalent bond
  • Ans 3: Example : H2 and Cl2 H-H, Cl-Cl
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 2

Question # 1

Why is the ionization energy of Na more than 'K'?

  • Ans 1: The first ionization of Na (495,8kJ/mol ) is greater than first ioniztaion energy of 'K' (418.8kJ(mol) and the atomic size of Na is less than 'K' so the energy required to remove an electron from outermost shell of Na is greater than that ok K ,so the ionization energy of Na is more than k
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 3

Question # 1

Describe the number of molecules in 9 g water.

  • Ans 1: Volume of water = 9g
  • Ans 2: No of molecules in a gram of water = 9/18
    = 0.5 mole
  • Ans 3: No of molecules in 9g gram of water molecules = 0.5x6.02x10 23
    = 3.01x1023
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 4

Question # 1

In electroplating of silver , from which electrolyte Ag+ comes and where they deposit ?

  • Ans 1: In the electrolyte of silver (Ag)+ comes from anode and deposit on cathode .
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 5

Question # 1

Write down the trend of atomic size in the periodic table.

  • Ans 1: In period : Atomic size in a period from left to right decreases
  • Ans 2: In group : Atomic size in a group from top to bottom increases due to increases in atomic number
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 6

Question # 1

Define transition element ?

  • Ans 1: d block elements called transition element
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 7

Question # 1

What is the nature of electrode used in electroplating of chromium?

  • Ans 1: The object to be electroplated acts as cathode while anode is made of antimonial-lead.
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 8

Question # 1

If repulsive forces dominate to attractive forces will a covalent bond form?

  • Ans 1: If the repulsive forces dominate to attractive forces the covalent will not be formed. The covalent bond formed only when the attractive forces dominates over the repulsive forces.
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 9

Question # 1

Write difference between electrolytic cell and galvanic cell.

  • Ans 1: Electrolytic cell :
    1: It consists of one complete cell. connected to battery
    2: Anode has positive charge while cathode have negative charge
    3: Electrical energy is converted into chemical energy
    4: Current is used for the non-spontaneous chemical reaction to take place
  • Ans 2: Galvanic cell:
    1: It consists of two half-cells connected through salt bridge
    2: Anode has negative charge while cathode has positive charge
    3: Chemical energy is converted into electrical energy
    4: Redox reaction takes place spontaneously and produces electric current
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 10

Question # 1

Differentiate between molecular mass and formula mas , which of the following is molecular formula ?
. H2O
.NaCl
.Kl
.H2SO4

  • Ans 1: Molecular mass :
    The sum of atomic masses of all the atoms present in one molecule of a molecular compound is its molecular mass

  • Ans 2: Formula : Molecular mass of water is 18 amu and that of carbon is 44 amu
  • Ans 3: Formula mass :
    Formula mass is the sum of atomic masses of all the atoms present in one formula unit of a substance
  • Ans 4: Example : Formula mass of sodium chloride is 85.5 amu and that of CaCO3 is 100 amu
  • Ans 5: H2O Or H2SO4 are molecular formula
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 11

Question # 1

What is by-products are produced in Down's cell?

  • Ans 1: Chlorine is produce in the downs cell as a by product
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 12

Question # 1

Give uses of platinum

  • Ans 1:
    Uses of platinum :
    1: Platinum is used in hard disk coating and in maufacturing fibre optic cables

  • Ans 2:
    2: Platinum is used in making jewellery .

  • Ans 3: 3: Platinum is also used in making plastic of fiberglass and glass of LCD
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 13

Question # 1

How many atoms are present in one gram atomic mass of a substance?

  • Ans 1: One gram atomic mass of a substance is equal to Avogadro's number in which 6.023 x 1023 atoms are present
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 14

Question # 1

Can colloids he separated by filtration, if not why?

  • Ans 1: Colloids cannot be separated by filtration because particles are big but they can pass through a filter paper.
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 15

Question # 1

Write difference between saturated solution and unsaturated solution .

  • Ans 1: Saturated solution : The solution containing maximum amount of solute at a given temperature is called saturated solution
  • Ans 2: Unsaturated solution : A solution which contain lesser amount of solute which is required to saturate a solution at particular temperature .
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 16

Question # 1

Calculate the oxidation number of nitrogen in HNO3 .

  • Ans 1: HNO3 = (1) +(N) +3 (-2)
    = 1+N-6
    N = +5
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 17

Question # 1

Why are dipole forces of attraction not found in halogen molecules?

  • Ans 1: Dipole forces of attraction do not found in halogen molecules because they have same electronegativity and there is equal sharing of electrons.
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 18

Question # 1

Who discovered proton and neutron ?

  • Ans 1: Proton is discovered by Goldstein in 1886
  • Ans 2: Neutronis discovered by James Chadwick in 1932
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 19

Question # 1

Why does chlorine accept an electron and attain -1 charge ?

  • Ans 1: Chlorine have seven electrons in its valence shell . It require one electron to complete its valence shell . That's why chlorine accept an electron and attain -1 charge
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 20

Question # 1

What is the capacity of the K,L,M,N shells ?

  • Ans 1: K shell can accommodate 2 electron
    L shell can accommodate 8 electrons
    M shell can accommodate 18 electrons
    N shell accommodate 32 electrons
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 21

Question # 1

Give two examples of gas in liquid solution .

  • Ans 1: 1: Fog
  • Ans 2: 2: Mist
  • Ans 3: 3: Liquid in pollutions
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 22

Question # 1

What does mean rusting of iron ?

  • Ans 1: Corrosion of iron is called rusting . The important condition for rusting is moist air
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 23

Question # 1

Why water is called universal solvent ?

  • Ans 1: Water is called universal solvent because it dissolves almost all the solute particles present in the world
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 24

Question # 1

Which metal is used for metal work?

  • Ans 1: As the metal work. means fire work. The metals are used in fire work due to its characteristic flame colour when they ignite in air . Na"- give golden colour, "Ca" give red colour etc.
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 25

Question # 1

If 16g of oxygen contains 1 mole of oxygen atom, calculate the mass of one atom of oxygen in grams .

  • Ans 1: No of atoms in one mole =6.02×1023
  • Ans 2: The mass of6.02×1023 atoms =16 g
  • Ans 3: The mass of one atom is = 16/6.02×1023
    = 2.657 x 10-25g
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 26

Question # 1

Write name of any two elements found in gaseous state

  • Ans 1: Nitrogen and oxygen both found in gaseous state
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 27

Question # 1

Name the elements represented by the following symbols W, Ba , Hg and Na

  • Ans 1: Tungsten W , Barium B , Mercury Hg , Sodium Na
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 28

Question # 1

Define effusion . Give example .

  • Ans 1: Effusion : Effusion is defined as the escaping of gas molecules through tiny holes into a space with lesser pressure
  • Ans 2: Example : when a tyre get punctured , air effuses out
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 29

Question # 1

Write short note on discovery of Neutron.

  • Ans 1: Chadwick discovered Neutrons in 1932 . He bombarded alpha particles on Beryllium . He observed that the radiation of very high penetrating power were produced ( They can move through long distance in air ) .These radiations were called Neutron
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 30

Question # 1

Write formulas of two ionic compounds which are soluble in water .

  • Ans 1: The two ionic compound which are soluble in water are following
  • Ans 2: Sodium chloride : NaCl
  • Ans 3: Sodium Thiosulphate : Na2S2O3
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 31

Question # 1

Molecular formula of a sulphur molecule

  • Ans 1: The Molecular formula of a sulphur molecule S8
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 32

Question # 1

Why is galvanizing done?

  • Ans 1: The process of coating a thin layer of zinc or iron is called galvanizing. Galvanizing is dot, because zinc protects the iron against corrosion even after the coating surface is broken.
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 33

Question # 1

Define allotropy and give examples .

  • Ans 1: The existence of an element in more than one form in same physical state but different chemical properties is called allotropy .
  • Ans 2: Example : Oxygen has two allotropic forms :
  • Ans 3: 1: Molecular oxygen =O2
  • Ans 4: 2: Ozone = O3
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 34

Question # 1

Why Lanthanides an Actanides are placed separately below periodic table . Explain

  • Ans 1: Because of space problem in periodic table two series of elements were placed separately below the normal periodic table to keep it in a manageable and presentable form . Since the two series start after Lanthanum (z=57) and Actinum (z=89) , so these two series of elements are named as Lanthanides and Actanides
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 35

Question # 1

What is the significance of the symbol of an element ?

  • Ans 1: Symbol means identification , in chemistry it is used for the representation of chemical name of an element . In chemical equation whole name of an element is difficult to write , because the formula or chemical equation becomes too lengthy . Thus symbol makes an easy representation and understanding in this case
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 36

Question # 1

When a gas is allowed to expand, what will be its effect on its temperature?

  • Ans 1: According to Charles' Law when gas is allowed to expand its temperature also increases.
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 37

Question # 1

In the basis of properties , elements are divided into which group ?

  • Ans 1: On the basis of properties elements are divided into metals , non-metals and metalloids
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 38

Question # 1

Differentiate between lone pair and bond pair of electron.

  • Ans 1:
    Lone Pair
    The non-bonded electron pair available on an atom. like the one lone pair is available on nitrogen in ammonia is called a lone pair
  • Ans 2: Bond pair : The bonded electron pair available within the atoms is called a bond pair
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 39

Question # 1

Why silver and gold are least reactive ?

  • Ans 1:
    From the transition metals of group 11 of periodic table Silover and Gold are least reactive because they do not lose electron easily

Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 40

Question # 1

Which form of Sulphur exists at room temperature?

  • Ans 1: Rhombic (S8) Sulphur exists at room temperature
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 41

Question # 1

Complete and balance the given chemical equation Na + H2➜ ?

  • Ans 1: 2Na + H2➜ 2NaH
    (Sodium ) (Hydrogen ) (sodium hydroxide )
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 42

Question # 1

How platinum is used as a catalyst in automobiles and what are advantages of this use ?

  • Ans 1: Platinum alloyed with palladium and rhodium is used as a catalyst in automobile as catalyst converter . It converts harmful gases into harmless gases
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 43

Question # 1

What is radical ?

  • Ans 1: An atom or a group of atoms that have some charge and keeps in contact during a chemical reaction is called a radical e,g Hydronium H3O+ and CO3 -2
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 44

Question # 1

What is the trend of variation in densities of alkali metals?

  • Ans 1: Densities of alkali metals increases down the group in the periodic table
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 45

Question # 1

What type of elements form metallic bond?

  • Ans 1: Metals form metallic bond
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 46

Question # 1

In which form sulphur exists at I00°C?

  • Ans 1: Sulphur exists in monoclinic form at 100"C because at room temperature sulphur exists in rhombic form. The transition temperature of sulphur is 96"C at which rhombic sulphur convened into monoclinic form.
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 47

Question # 1

Define Chemistry?

  • Ans 1: The Branches of Science which deals with the composition, structure, properties and reactions of matter is called chemistry.
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 48

Question # 1

Write down use of paints and greases .

  • Ans 1: 1: Greasing or painting of the surface can prevent the corrosion of iron
  • Ans 2: 2: With development of technologies , modern paints contains a combination of chemicals called 'stablizers ' that provide protection against the weathering and other atmospheric effects
  • Ans 3: 3: Iron can be prevented from rusting by applying layer of grease
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 49

Question # 1

Define modern periodic law ?

  • Ans 1: In 1913 H.Moseley given Modern law
    Properties of elements are periodic function of their atomic masses
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 50

Question # 1

Write four physical properties of calcium metals .

  • Ans 1: 1: Calcium is silvery grey and fairly harder metal
  • Ans 2: 2:Good conductor of heat and electricity
  • Ans 3: 3: Melting point of 839°C
  • Ans 4: 4: Flame colour of calcium metal is brick red
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 51

Question # 1

What are the defects of Mendeleev's periodic table or why improvement was make in Mendeleev's periodic table?

  • Ans 1: There are two defects in Mendeleev's periodic table:

  • Ans 2: 1: His failure to explain the position of isotopes
  • Ans 3: 2: Wrong order of atomic masses of some elements
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 52

Question # 1

Define brine ?

  • Ans 1: The by-product in Nelson's cell are hydrogen gas (H2) and chlorine gas (Cl2)
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 53

Question # 1

Define organic chemistry and which industries covered by it

  • Ans 1: Organic chemistry : it is the study of covalent compounds of carbon and hydrogen and its derivatives
  • Ans 2: Scope : This branch of chemistry determine the structure and properties of theses naturally occuring as well as synthesized compounds
  • Ans 3: This branch also covers the petroleum , petrochemicals and pharmaceutical industries
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 54

Question # 1

What is meant by octet rule ?

  • Ans 1: Attaining 8 electrons in the outermost shell either by sharing by losing or gaining electrons is called octet rule . Atoms complete their octet by gaining , giving or sharing valence electrons with other atoms
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 55

Question # 1

What is classical theory of radiation . How it is differ from quantum theory ?

  • Ans 1: According to classical theory of radiation electrons being the charge particle should release energy continuously and they should ultimately fall into a nucleus . It differ from quantum theory because quantum means fixed energy it is the smallest amount of energy that can be emitted or absorb as electromagnetic radiation
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 56

Question # 1

Define pascal .It is the unit of which quantity ?

  • Ans 1: If one newton force is applied on 1m2area then pressure is called one pascal . It is unit of pressure
  • Ans 2: Unit : 1 Pa = 1N/1m2
    = Nm-2
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 57

Question # 1

How are elements are arranged in 4th period ?

  • Ans 1: In fourth period 18 elements are arranged in the ascending order of their atomic number
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 58

Question # 1

Why does group 1 elements prefer to combine with group 17 elements.

  • Ans 1: The elements of Group-1 being metals have the tendency to lose their valence electrons forming positively charged ions. Whereas non-metals of Group-17 have the tendency to gain or accept electrons. They are electronegative elements with high electron affinities. If atoms belonging to these two different group, metals and non-metals, are allowed to react. chemical bond is formed
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 59

Question # 1

Write four examples of mixture .

  • Ans 1: 1: Air is a mixture of nitrogen , carbon dioxide , noble gasses and water vapours
  • Ans 2: 2: Solid us a mixture of sand , clay , mineral salts , water and air
  • Ans 3: 3: Milk is a mixture of water , sugar k, fat , proteins , minerals , salts and vitamins
  • Ans 4: 4: Brass is a a mixture of copper and zinc metals
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 60

Question # 1

Differentiate between molecular mass and formula mas , which of the following is molecular formula ?
. H2O
.NaCl
.Kl
.H2SO4

  • Ans 1: Molecular mass :
    The sum of atomic masses of all the atoms present in one molecule of a molecular compound is its molecular mass

  • Ans 2: Formula : Molecular mass of water is 18 amu and that of carbon is 44 amu
  • Ans 3: Formula mass :
    Formula mass is the sum of atomic masses of all the atoms present in one formula unit of a substance
  • Ans 4: Example : Formula mass of sodium chloride is 85.5 amu and that of CaCO3 is 100 amu
  • Ans 5: H2O Or H2SO4 are molecular formula
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 61

Question # 1

Why metals are good conductor of electricity ?

  • Ans 1: Metals are good conductors of heat and electricity in solid and liquid state due to mobile electrons
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 62

Question # 1

What are trends of ionization energy in periodic table ?

  • Ans 1: Ionization energy increases from left to right in the period while it decreases from to bottom in a group
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 63

Question # 1

hat is the importance of oxygen and carbon dioxide for plants and animals ?

  • Ans 1:
    Life owes to non-metals as without O2 and CO2 those are essential gases for respiration of animals and plants respectively , life would not have been possible . In fact these
    gases are essential for the existance of life
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 64

Question # 1

Why alkali metals are extremenly reactive ?

  • Ans 1:
    Alkali metals : The elements in the first group of the periodic table are calleed alkali metals
    Reactive of alkali metals :
    Alkali metals are extrmely reactive elements because of their ns 1 valence shell electronic configuration . These metals only have one electronin theor valence shell , which can be easily
    given out
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 65

Question # 1

How are elements are arranged in 4th period ?

  • Ans 1: In fourth period 18 elements are arranged in the ascending order of their atomic number
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 66

Question # 1

What is meant by ion ? Give example .

  • Ans 1: Ion is an atom or group of atoms having a charge on it .
  • Ans 2: For example , sodium Na+ and potassium K+ both are ions
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 67

Question # 1

Why do the bigger size atoms have more shielding effect?

  • Ans 1: In bigger size atoms the number of inner shells and inner shell electrons increases hence the shielding effect in bigger size molecules also increases.
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 68

Question # 1

Name the metal which is least conductor of heat ?

  • Ans 1: Lead is a metal which is least conductor of heat
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 69

Question # 1

Why do the bigger size atoms have more shielding effect?

  • Ans 1: In bigger size atoms the number of inner shells and inner shell electrons increases hence the shielding effect in bigger size molecules also increases.
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 70

Question # 1

Give the characteristics properties of ionic compounds

  • Ans 1: the characteristic properties of ionic compounds. %Its: Characteristic Properties of Ionic Compounds: (I) lanai compounds are mostly crystalline solids. In I Ionic compounds in solid state have negligible electrical conductance but they are good conductors in solution and in the molten form. It is due to presence of free inns in them. lilt) Ionic compounds have high melting and boiling point example. NaCI has M.P. 800°C and B.P. 1413°C. (iv) Ionic compounds dissolves in polar solvents. Like NaCI dissolves in water.
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 71

Question # 1

Why water is called universal solvent ?

  • Ans 1: Water is called universal solvent because it dissolves almost all the solute particles present in the world
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 72

Question # 1

What is difference between compound and mixture / Give example .

  • Ans 1: Compound :
    1:It is formed by chemical combination of atoms of element
    2:Its components lose their own properties and produce new substance that have entirely different properties
  • Ans 2: Mixture :
    1: It is formed by the simple mixing up of the substances
    2: Its components retains their own chemical identities and properties
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 73

Question # 1

Why covalent bond in H2 is non-polar ?

  • Ans 1: In H2 covalent bond is formed between two similar atoms , the shared pair of electron is attracted by both atoms equally , so non-polar covalent bond exist between hydrogen atoms
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 74

Question # 1

Write down any two properties of metals .

  • Ans 1: 1: They show metallic luster
  • Ans 2: 2: They are usually malleable andductile
  • Ans 3: 3: Being greater in size they have low ionization energies and form cation (M+) very easily
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 75

Question # 1

What is the principle of electroplating ?

  • Ans 1: Principle of electroplating is to establish an electrolytic cell in which anode is made of the metal to be deposited and cathode of the object on which metal is to deposit . The electrolyte is an aqueous solution of salt of the respective metal
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 76

Question # 1

When do electrons emit or absorb energy ?

  • Ans 1: A long as electron remain in a particular orbit it does not radiate or absorb energy, The energy is emitted or absorbed only when an electron jumps from one orbit to another
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 77

Question # 1

Name the element of 1st period of periodic table

  • Ans 1: 1st period consists only two elements hydrogen (H2|) and Helium ( He)
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 78

Question # 1

Define the coordinate covalent bond? Explain with one example .

  • Ans 1: Coordinate covalent bond or dative bonding is a type of covalent bonding in which the bond pair of electrons is donated by one bonded atom only . Coordinate covalent bond is also known as Dative covalent bond
  • Ans 2: The atom which donates the electron pair is called donor and the atom which accepts the electron being donated . The head of arrow is towards the acceptor atom
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 79

Question # 1

How many neutrons are present in C-12 and C-13 ?

  • Ans 1: C-12 C-13
    P=6 P=6
    N=12-6=6 N=13-6=7
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 80

Question # 1

Why does atomic size increases in a group ?

  • Ans 1: The size of atoms or their radii increases from top to bottom in a group . It is because a new shell of electrons is added up the successive period . Which the effect of nuclear charge
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 81

Question # 1

Why an iron grill is painted frequently?

  • Ans 1: Iron grill is painted frequently because due to presence of oxygen and water in air. It become, corrode. So to prevent it front rusting it is painted
Submit

9th Class Chemistry English Medium Chapter 1 Preparation - Set 82

Question # 1

Describe the chemical reaction of alkaline earth metals with hydrogen .

  • Ans 1: Alkaline metals :
    Reaction with oxygen :
    1: Alkaline metals immediately tarnish in air giving their oxides which form strong alkalies in water
    4Na +O➜ 2Na2 O
    Na2 O➜ 2NaOH
    2: Reaction with hydrogen :
    The form ionic hydrides with H2at high temperature
    2Na +H2➜2NaH
    Reaction with Halogens :
    3: They react violently with halogens at room temperature to give halides
    2Na +Cl2➜ 2NaCL
  • Ans 2: Alkaline earth metals
    1: Alkaline earth metals are less reactive toards oxygen and oxides are formed on heating
    2Mg +O➜ 2MgO
  • Ans 3: 2: They give hydrides under strong conditions of temperature and pressure
    Ca +H➜ CaH2
  • Ans 4: 3: They react slowly with halogens to give their halides
    Ca+Cl2➜ CaCl2
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9th Class Chemistry English Medium Chapter 1 Preparation - Set 83

Question # 1

Where sodium metal is obtained from fused sodium chloride .

  • Ans 1: Sodium metal accumulates at iron cathode in down's cell
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9th Class Chemistry English Medium Chapter 1 Preparation - Set 84

Question # 1

What are two factors on which evaporation depends ?

  • Ans 1: Surface area : Evaporation is a surface phenomenon . Greater is surface area greater is evaporation
  • Ans 2: Temperature : At high temperature , rate of evaporation is high because at high temperature kinetic energy of the molecules increases so high that they overcome the intermolecular forces and evaporate rapidly
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9th Class Chemistry English Medium Chapter 1 Preparation - Set 85

Question # 1

How many atoms of hydrogen present in 1 mole of water ?

  • Ans 1: 1 mole of water = 6.02 x 1023molecules
    1 mole of water has H atom =1x 6.02x1023atoms
    = 6.02 x 1023
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9th Class Chemistry English Medium Chapter 1 Preparation - Set 86

Question # 1

What are cathode rays ? Who discovered it?

  • Ans 1: In 1897 JJ Thomson discovered cathode rays
  • Ans 2: Cathode rays :

    1: These rays travel in a straight line perpendicular to the cathode surface
  • Ans 3: 2:They can cast a sharp shadow of an opaque object if placed in their path
  • Ans 4: 3: They are negatively charged
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9th class Chemistry Chapter 1 Preparation

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