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

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

Question # 1

Write down the chemical formula of silicon dioxide and calcium chloride .

  • Ans 1: Silicon dioxide SiO2
  • Ans 2: Calcium chloride CaCl2
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

Write down the chemical formula of silicon dioxide and calcium chloride .

  • Ans 1: Silicon dioxide SiO2
  • Ans 2: Calcium chloride CaCl2
Submit

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

Question # 1

Difference between true solution and colloid solution?

  • Ans 1: True solution:Solutions are the homogeneous mixture of two or more than two components.
  • Ans 2: Colloid :Colloid are solution in which the solute particles are larger than those parent in the true solution, but not large enough to be seen by thenaked eye.
Submit

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

Question # 1

In which pattern modern periodic table was arranged?

  • Ans 1: According to increasing atomic number.
Submit

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

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
Submit

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

Question # 1

Why atomic number is more fundamental property to arrange elements than atomic mass?

  • Ans 1: Due to two reasons :
    1: It increase regularly from element to element
  • Ans 2: 2: It is fixed for every element
Submit

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

Question # 1

For what purpose P-32 and Sr - 90 are used .

  • Ans 1: 1: For the treatment of skin cancer , isotopes like P-32 and Sr-90 are used because they emit less penetrating beta radiations
  • Ans 2: 2: For cancer , Co-60 affecting within the body , is used because it emits strongly penetrating gamma rays
Submit

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

Question # 1

What do you mean by group or median in periodic table ?

  • Ans 1: The horizontal rows in periodic table called periods and vertical columns in the periodic table are called groups
Submit

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

Question # 1

Write down melting point and boiling point of sodium metal .

  • Ans 1: Melting and boiling point of sodium metal are as follows
  • Ans 2: Melting point :97°C
  • Ans 3: Boiling point : 883°C
Submit

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

Question # 1

Give few properties of cathode rays .

  • Ans 1: a: These rays travel in a straight line perpendicular to the cathode surface
  • Ans 2: b: They raise the temperature of the body on which they fall
  • Ans 3: c: They can cast a sharp shadow of an opaque object if placed in their path
  • Ans 4: d: J.J Thomson discovered their charge / mass / ,e/m ratio
Submit

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

Question # 1

What is the significance of the symbol of an elements?

  • Ans 1: Significance of the symbol of an element: Symbols are used for elements instead of writing of their complete names. So, it takes less time save time and element can be recognized by that symbol in all over the world. For example oxygen,sulphur, Nitrogen
Submit

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

Question # 1

Write down names of any two moderate reactive metals

  • Ans 1: 1: Magnesium
  • Ans 2: 2: Silver
Submit

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

Question # 1

Why does evaporation increases with the increase in temperature ?

  • Ans 1: Evaporation increase with the increase of temperature because at high temperature K.E of the molecules increase so high that they overcome the intermolecular forces and evaporate rapidly
Submit

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

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 14

Question # 1

What are electrolytic cell ?

  • Ans 1: Electrolytic cell : The type of electrochemical cell in which the non-spontaneous chemical reaction is carried out with the help of electric current is called electrolytic cell
  • Ans 2: Example : Down's cell, Nelson's cell
Submit

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

Question # 1

Define halogens . give example .

  • Ans 1:
    Halogens : The element of group 17 called halogens
    Example : Chlorine , Fluorine , Bromine etc

Submit

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

Question # 1

What is difference between Duplet rule and octet rule ?

  • Ans 1: Duplet rule : Attaining two electrons in the valence shell is called duplet rule
  • Ans 2: Octet rule : Attaining eight electrons in the valence shell is called octet rule
Submit

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

Question # 1

What is the difference between diffusion and effusion ?

  • Ans 1: Diffusion: The spontaneous mixing of molecules by random motion and collision of gases form homogenous mixture is called diffusion
  • Ans 2: Example: Mixing of ink drop in the glass of water
  • Ans 3: Effusion : Effusion is defined as the escaping of gas molecule through tiny hole into a space with lesser pressure
  • Ans 4: Example : Puncture of tyre
Submit

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

Question # 1

What are weak electrolytes? . Give example .

  • Ans 1: The substances which ionize to a small extent when dissolved in water and could not produce more ions are called weak electrolytes
  • Ans 2: Example : CH3COOH and Ca (OH)2 ionize to a small extent in aqueous solution . Therefore these are weak electrolytes
Submit

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

Question # 1

Define electronic configuration ?

  • Ans 1: Electronic configuration : The distribution of electrons around the nucleus in various shells and sub-shells according to increasing energy , is called electronic configuration
Submit

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

Question # 1

Why does 10 g nitrogen gas contain the same number of molecules as 10g of carbon monoxide ?

  • Ans 1: Number of moles of nitrogen gas = 10/28 =0.35mol
    Number of molecules of N2 = 0.35x0.22x1023
    =2.107x1023
  • Ans 2: Number of moles of carbon monoxide gas = 10/28 = 0.35 mol

  • Ans 3: Number of molecules of CO2 gas = 0.35x6.022x1023
    = 2.107x1023
Submit

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

Question # 1

What is the nature of charge on cathode ray ?

  • Ans 1: Cathode rays are deflected toward positive plate in an electric field showing that they are negatively charged
  • Ans 2: These rays are originated from cathode of discharge tube
Submit

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

Question # 1

What is solid-liquid solution ? Explain with example .

  • Ans 1: When a solid dissolves in liquid and form solution called solid-liquid solution . If sugar dissolve in water it will be called solid-liquid solution.
Submit

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

Question # 1

Define atomic number and atomic mass .

  • Ans 1: Atomic mass :
    1: The sum of number of protons and neutrons present in the nucleus of an atom is called atomic mass
    2: It is represented by A
    Example : Atomic mass of carbon is 12
  • Ans 2: Atomic number :
    1:The number of protons present in the nucleus of an atom is called atomic number
    2: It is represented by Z
    Example : Atomic number of carbon is 6
Submit

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

Question # 1

What is difference between elements and compound ?

  • Ans 1: Compound : Compound is a substance made up of two or more elements chemically combined together in a fixed ratio by mass
    Example : Water (H2O)
  • Ans 2: Element : Element is the substance made up of same type of atom , having same atomic number and cannot be decomposed into simple substance by chemical ways
    Example : Sodium : (Na) Copper : (Cu)
Submit

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

Question # 1

What is difference between ion and free radical ?

  • Ans 1: Free radicals :
    1: These are the atoms that have odd number of electrons . They do not have any charge
    2: They can exists in solutions as well as in air
    3: They may form in the presence of light
  • Ans 2: Ion
    1:These are the atoms which bear some charge
    2: They can exists in solutions or in crystal lattice
    3: Their formation is not affected by the presence of light
Submit

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

Question # 1

Write electronic configuration of chlorine and carbon

  • Ans 1: Electronic configuration of carbon : 12 C 6 = 1s2 , 2s2 , 2p2
  • Ans 2: Electronic configuration of chlorine : 17 Cl = 1S2 , 2S2, 2P6, 3S2, 3P5
Submit

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

Question # 1

How was it shown that atomic nuclei are positively charged ?

  • Ans 1: The deflection of a few particles proved that there is a center of positive charge in an atom , , which is called nucleus of an atom
Submit

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

Question # 1

Which of the following will scatter light and why?
Sugar solution, Soap solution, Milk of magnesia.

  • Ans 1: Soap solution is colloidal solution and have particles large enough to scatter the light
Submit

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

Question # 1

Define carbondating .

  • Ans 1: 1: The radioactive isotopes are used to estimate the age of fossils like dead plants and animals and stones etc . The age determination of very old objects based on the half-lives of the radioactive isotopes is called radioactive isotopes is called radioactive-isotopes dating
  • Ans 2: 2: An important method of age determination of old carbon containing objects ( fossils ) by measuring the radio-carbon dating or simple carbon dating
Submit

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

Question # 1

Which allotropic form of carbon is stable at room temperature (25°C)?

  • Ans 1: Graphite is more stable at room temperature
Submit

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

Question # 1

Which factors affect the non-metallic character ?

  • Ans 1:
    Non-metallic character depends upon Electron affinity and electronegativity

Submit

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

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 33

Question # 1

Why does a dipole develop in a molecule ?

  • Ans 1: The unequal sharing of electrons between two different types of atoms make one end of molecule slightly positive and other end slightly negatively charged . As shared pair of electron is drawn towards more electronegative atom , it is partially negatively charged . The other end automatically becomes partially positively charged
Submit

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

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 35

Question # 1

State whether allotropy is shown by elements or compounds or both ?

  • Ans 1: Allotropy is only shown by elements . It is not a property of compounds
Submit

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

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 37

Question # 1

What is relation between electropositivity and ionization energy ?

  • Ans 1: Electropositivity is the reverse of the ionization energy . In the from from top to bottom ionization energy decreases and electropositivity increases
Submit

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

Question # 1

Calculate the molecular mass of the carbon dioxide .

  • Ans 1: Molecular mass of the carbon dioxide
    CO2 = 12+2 (16)
    = 44amu
Submit

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

Question # 1

Give example of two polar compounds and give their chemical formula .

  • Ans 1: Following are some examples of two polar compounds :
  • Ans 2: 1: Hydrochloric or Hydrogen chlorine (HCL)
  • Ans 3: 2: Water (H2O)
  • Ans 4: 3: Hydrogen fluoride (HF)
Submit

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

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 41

Question # 1

What are the elements arranged in group 3 to 12 called ?

  • Ans 1: The groups 3 to 12 are called transition elements . In these elements 'd ' sub shell is in the process completion
Submit

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

Question # 1

Why ionization energy ok alkaline earth metals is higher than alkali metals?

  • Ans 1:
    The size of alkali metals is samaller than alkaline earth metals that's why they have high ionization energy

Submit

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

Question # 1

What is meant by atomic radius ? What is its unit ?

  • Ans 1: The half of the distance between the nuclei of two of similar adjacent (bonded) atoms is called atomic radius
  • Ans 2: Its unit is pico meter (pm)
Submit

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

Question # 1

How molar solution is prepared ?

  • Ans 1: One molar solution is prepared by dissolving 1 mole of the solute in sufficient water to make the total volume of solution upto 1 dm3 in a measuring flask
  • Ans 2: Example : 1 M solution of NaOH is prepared by dissolving 40g of NaOH in sufficient water to make the total , volume 1 dm3
Submit

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

Question # 1

Write down the name of any two elements which were discovered in early ages .

  • Ans 1: Following elements were discovered in early ages
  • Ans 2: 1: Crbon
  • Ans 3: 2: Gold
  • Ans 4: 3: Silver
  • Ans 5: 4: Copper
Submit

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

Question # 1

What is difference between solute and solvent ?

  • Ans 1: Solute : The component of the solution which is present in smaller quantity is called solute
  • Ans 2: Example : Salt dissolve in water, where salt is solute
  • Ans 3: Solvent : The component of the solution which is present in greater quantity is called solvent
  • Ans 4: Example : Salt dissolves in water where water is solvent
Submit

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

Question # 1

WHat do you know about the oxidizing characteristics of halogens ?

  • Ans 1:
    Chlorine is the most poweful oxidizing agent. Oxidizing property of halogens is decreased from top to bottom . All halogens react with hydrogen gbas in the
    presence of light and catalyst to make halides . Stability of their hydrogen halides are given below
    HF > HCL > HBR > HI

Submit

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

Question # 1

How electroplating of zinc is carried out ?

  • Ans 1: The target metal is cleaned in alkaline detergent type solutions , and it is treated with acid , in order to remove any rust or surface scales. Next the zinc is deposited on the metal by immersing it in a chemical bath containing electrolyte zinc sulphate . A current is applied , which results in zinc being deposited on the target metal i-e cathode
Submit

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

Question # 1

What is meant by dipole dipole forces of attraction ?

  • Ans 1: When partial positive and partial negative charges exists at different positions in a molecule , the adjacent molecules will arrange themselves in such a way that negative end of that molecule comes near to positive end of other molecule . It results in a net forces of attraction between oppositely charged ends of two adjacent molecules . These attractive forces are called dipole - dipole forces
Submit

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

Question # 1

What is meant by molecular ion ?

  • Ans 1:
    When a molecule loses or gains one or more electron , it forms a molecular ion

  • Ans 2:

    Example : CH4
Submit

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

Question # 1

Give one example each of the use of radioactive isotope in medicine and radiotherapy ?

  • Ans 1: Radioactive isotopes is used in medicine
    Iodine 131
    Radioactive isotopes used in radiotherapy
    P-32
    Sr-90
    Co-60
Submit

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

Question # 1

Can pure gold be used for making ornaments?If not why?

  • Ans 1:
    No. pure gold cannot be used for making ornaments.
    because gold is too sift to be used as such It is always alloyed with copper. silver and some other metals

Submit

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

Question # 1

Differentiate between empirical and molecular formula .

  • Ans 1: Empirical formula: It is the simplest whole number ratio of atoms present in a compound
  • Ans 2: e.g Empirical formula of benzene is CH
  • Ans 3: Molecular formula : It shows actual number of atoms of each element present in a molecule of that compound
  • Ans 4: e.g Molecular formula of benzene is C6H6
Submit

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

Question # 1

Give application of silver ?

  • Ans 1: 1: Compound of silver are widely used in photographic films
  • Ans 2: 2: It is used in dental preparation
  • Ans 3: 3: It is highly ductile and malleable metals that is why it is used to make coins silver-wares and ornaments
  • Ans 4: 4: Silver also has important applications in mirror industry
Submit

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

Question # 1

How a covalent bond becomes polar?

  • Ans 1:
    When a covalent bond is formed between two different atoms having different electronagetivity then the bond pair of electron will not be attracted equally by the bonded atoms as a result partial positive and negative charges appear on atoms and covalent bond becomes polar.

Submit

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

Question # 1

What is the relationshp between atomic number and atomic mass?

  • Ans 1: The relation between atomic number and atomic mass is as following A = Z + n
Submit

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

Question # 1

Define polar covalent bond with example .

  • Ans 1: Polar covalent bond is formed between two different atoms when the shared pair of electrons are not attracted equally by bonded atoms. The compounds resulting from covalent bond are called polar compounds
  • Ans 2: Example HCL is the example ofpolar covalent bond.
Submit

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

Question # 1

What was the thickness of gild foil used in Rutherford's atomic model ?

  • Ans 1: 0.00004 cm thick gold foil was used by Rutherford in his experiment
  • Ans 2:
Submit

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

Question # 1

An element has 5 electron in M shell . Find out its atomic number ?

  • Ans 1: The number of this element will be 15
Submit

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

Question # 1

Which branch of chemistry deals with energy of atoms and its uses in daily life.

  • Ans 1: Nuclear chemistry deals with energy of atoms and its uses in daily life.
Submit

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

Question # 1

Why does covalent bond become polar?

  • Ans 1: If the covalent bond is formed between two different atoms bond pair of electrons will not attracted equally by the bonded atoms . The atom which has greater electronegativity will attract bond pair more towards itself than other atom and hence molecule will become polar
Submit

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

Question # 1

Why sodium metal is more reactive than magnesium metal?

  • Ans 1: Sodium metal is more reactive than magnesium metal because electro-positivity of met increase along the periods from left to right in periodic table. Element in the start of the period are more metallic or electropositive. Across the period from left to right size of atoms decreases due to increase in nuclear charge. That's why, sodium is more reactive than magnesium.
Submit

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

Question # 1

Why densities of gases are less than liquids ?

  • Ans 1: Gases have low density than liquids and solids . It is due to light mass and more volume occupied by the gas molecules . Gas density is expressed in grams per dm3. Whereas liquid and solid densities are expressed in grams per cm3 i-e liquids and solids are 1000 time denser than gases
  • Ans 2: Example : At normal atmospheric pressure , the density of oxygen gas is 1.4g dm-3 at 20° C and 1.5 gdm-3 at0°C
Submit

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

Question # 1

Why does reactivity of metals increase down the group?

  • Ans 1: The reactivity of metals increase down the group due to increase in atomic size and shielding effect down the group . The ability of the metals to loose electrons increase down the group and ionization energy also decrease hence their reactivity increase down the group
Submit

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

Question # 1

Why size of an atom decreases from left to right in the periodic table?

  • Ans 1: When we move from left to right in a periodic atomic number increase yet the size of atoms decrease gradually . It is because with the increase of atomic number and nuclear charge
Submit

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

Question # 1

Write two method for prevention of corrosion .

  • Ans 1: Method for prevention of corrosion:
    Following are some method from avoiding corrosion
  • Ans 2: 1: Paints and grease:
    Greasing or painting of the surface can prevent the rusting of iron
  • Ans 3: 2: Alloying :
    Allowing of iron with other metals has proved to be very successful techniques against rusting and corrosion . The best example of this technique is stainless steel
  • Ans 4: Removal of stains : The regions in an iron rod act as the site for corrosion . If the surface of iron is properly cleaned and stains are removed , it would prevent rusting
Submit

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

Question # 1

What is tyndall effect ? On which factor it depends ?

  • Ans 1: Tydnall effect: The particles of colloids are big enough to scatter the beam of light . It is called tydnall effect
  • Ans 2: Factors depends upon tydnall effect :
    It depends upon size of solute particles
Submit

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

Question # 1

Give chemical reaction of methane with chlorine in bright light .

  • Ans 1:
    In bright light (sun light) Cl2 react with CH4 violently and explosively
    Chemical reaction : CH4 +2Cl2 ➜ C+4HCL
Submit

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

Question # 1

Differentiate between atom and ion ?

  • Ans 1: Atom :
    1: It is the smallest particle of an element
    2: It can or cannot exists independently and can take part in a chemical reaction
    3: It is electrically neutral
  • Ans 2: Ion:
    1: It is the smallest unit of an ionic compound
    2: It cannot exists independently and is surrounded by oppositely charged ions
Submit

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

Question # 1

Why magnesium is harder than sodium?

  • Ans 1: Magnesium is harder than sodium because in magnesium metallic bonding is stronger. While sodium is relatively soft metal due to weak metallic bonding in their atoms.
Submit

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

Question # 1

What is the reason of deficiency of electrons in BF3?

  • Ans 1: In the formation ofBF3molecules , three valence electrons of boron (B) make three pairs of mutual coordination with three valance electrons from three fluorine atoms .. Despite of covalent bond made due to this mutual coordination , there is still deficiency of electron in boron . That's why octate is still incomplete (BF3)
  • Ans 2: Formation of coordinate covalent bond in BF3 and NH3, If an ammonia molecule (NH3) which has lone pair come close to the boron tri fluoride molecule (BF3) then ammonia give a lone pair to boron tri fluoride (BF3) to fulfil the deficiency of electrons . In this way NH3 become electron pair donor and BF3 become electron pair acceptor
Submit

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

Question # 1

Difference between true solution and colloid solution?

  • Ans 1: True solution:Solutions are the homogeneous mixture of two or more than two components.
  • Ans 2: Colloid :Colloid are solution in which the solute particles are larger than those parent in the true solution, but not large enough to be seen by thenaked eye.
Submit

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

Question # 1

What is valency ?

  • Ans 1: The combining capacity of an element with other element is called valency
  • Ans 2: For example : Valency of carbon is 4
Submit

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

Question # 1

Write two properties of platinum.

  • Ans 1:
    1: Platinum is a noble metal and very least reactive
  • Ans 2: 2: Platinum metal has characteristics colir , beauty , strenght elasticity and lust
Submit

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

Question # 1

Write the redox reaction taking place during the electroplating of chromium.

  • Ans 1: Reaction at the electrodes are as Follows:
    At anode 40H-➜2H2O+O2+4e-
    At cathode C+33e-➜Cr
Submit

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

Question # 1

State the physical properties of sodium .

  • Ans 1: 1: Its melting point is 97°C
  • Ans 2: 2: Sodium is silvery white having a metallic lusture very soft and can be cut with knife
Submit

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

Question # 1

How cation and anion is formed ?

  • Ans 1: Cation is formed by the loss of one or more electrons
  • Ans 2: Anion is formed by the gain of one or more electrons
Submit

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

Question # 1

Define standard atmospheric pressure . What are its units ? How it is relate to the pascal ?

  • Ans 1: It is defined as the pressure exerted by a mercury column of 760 mm height at sea level
  • Ans 2: 1atm = 760mmof Hg =760torr
    =101325 Nm-2 = 101325Pa
Submit

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

Question # 1

Define molarity and write its equation .

  • Ans 1: It is a concentration unit defined as number of moles of solute dissolved in one dm3 of solution . It is represented by M.
  • Ans 2: Formula :
    Molarity = No.of moles of solute / Volume of solution (dm3)
  • Ans 3: Molarity M = Mass of solute (g) /Molar mass of solute (gmol -1) x Volume of solution x (dm-3)
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9th Class Chemistry English Medium Chapter 1 Preparation - Set 80

Question # 1

What is a plum pudding theory ?

  • Ans 1: Thomson put forth his plum pudding theory . He postulated that atoms were solid structure of positively charge with tiny negative particle stuck inside . It is like plum in a pudding
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9th Class Chemistry English Medium Chapter 1 Preparation - Set 81

Question # 1

What is the shape of cathode in the Nelson's cell ? Why is it perforated ?

  • Ans 1: The cathode in Nelson's cell is U- shaped . It is perforated for the percolation of NaoH into a catch basin
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9th Class Chemistry English Medium Chapter 1 Preparation - Set 82

Question # 1

What is diffusion ? Explain with example ?

  • Ans 1: Diffusion is defined as spontaneous mixing up of molecules by random motion and collisions to form a homogeneous mixture
  • Ans 2: Example : H2 diffuses four times faster than O2 gas
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9th Class Chemistry English Medium Chapter 1 Preparation - Set 83

Question # 1

Name the particle which determine the mass of an atom ?

  • Ans 1: Protons and neutrons determine the mass of an atom
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9th Class Chemistry English Medium Chapter 1 Preparation - Set 84

Question # 1

Define electrochemistry .

  • Ans 1: Electrochemistry is a branch of chemistry that deals with the relationship between electricity and chemical reaction
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9th Class Chemistry English Medium Chapter 1 Preparation - Set 85

Question # 1

Which allotropic form of carbon is stable at room temperature (25°C)?

  • Ans 1: Graphite is more stable at room temperature
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9th class Chemistry Chapter 1 Preparation

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