Atoms, Molecules and Chemical Arithmetic MCQs Part 22

Atoms, Molecules and Chemical Arithmetic MCQs

This is continuous series of chemistry MCQs, so in this post we cover 20 MCQs of chapter Atoms, Molecules and Chemical Arithmetic.

MCQ-1.  What is SI unit of temperature :

  Fahrenheit
  Centigrade
  Absolute
  Kelvin

MCQ-2.  Prefix 10¹⁸ is :

  Giga
  Nano
  Exa
  Mega

MCQ-3.  Derived SI Unit of Area is :

  cm²
  cm³
  m²
  m³

MCQ-4.  Which one of the following is a physical change :

  Burning of carbon in air
  Burning of sulphur in air
  Conversion of white phosphorus to red phosphorus
  corrosion of metals

MCQ-5.  Law of Multiple Proportions was proposed by which of the following scientist :

  Lavoisier
  Proust
  Gay-Lussacs
  Dalton

MCQ-6.  Which pair of compounds illustrate the law of multiple proportions :

  H₂S and SO₂
  FeCl₂ and FeCl₃
  CuO and Cu₂O
  NH₃ and NCl₃

MCQ-7.  The ratio of the rates of the diffusion of a given element to that of helium is 4. what is the molecular weight of the element :

  0.25
  2
  4
  0.65

MCQ-8.  The Law of Reciprocal proportions can be used to determine :

  Atomic weight of a gas
  molecular weiht of gases
  equivalent weights
  all of these

MCQ-9.  The specific heat of a metal is 0.16 , its approximate atomic weight would be _____________ :

  16
  32
  40
  64

MCQ-10.  Atomic weight of a trivalent element of equivalent weight 9 is_____ :

  27
  36
  18
  9

MCQ-11.  Which property of element is always a whole number :

  Atomic weight
  Atomic Number
  Atomic Volume
  Equivalent Weight

MCQ-12.  A metallic oxide contains 60% of the metal. The equivalent weight of the metal is ________ :

  48
  24
  12
  40

MCQ-13.  Equivalent weight of an acid is _______ whose basicity is 3 :

  Molecular Weight/1
  Molecular Weight/2
  Molecular Weight/3
  Molecular Weight/4

MCQ-14.  90 gram of water contains how many moles :

  6.02x10²³
  1
  5
  90

MCQ-15.  which one of the following has maximum number of atoms :

  24 gram of C (12)
  56 gram of Fe (56)
  26 gram of Al (27)
  108 gram of Ag(108)

MCQ-16.  18 gram of water contains :

  1 gram of hydrogen
  2 gram of hydrogen
  3 gram of hydrogen
  4 gram of hydrogen

MCQ-17.  volume of 4.4 gram of carbon di oxide at STP is________ :

  22.4 litres
  2.24 litres
  44.8 litres
  4.48 litres

MCQ-18.  Avogadro Number of Helium atom weighs ______ gram :

  1
  2
  4
  8

MCQ-19.  A hydrocarbon containing 86% carbon. 448 mL of the hydrocarbon weighs 1.68 gram at STP, Then hydrocarbon is an __________ :

  arene
  alkane
  alkene
  alkyne

MCQ-20.  The % of nitrogen in urea is about________ :

  18
  36
  38
  46

Chemistry formulas for Atoms, Molecules and Chemical Arithmetic Part I

Atomic Weight related Chemical Formulas

·         Atomic Weight of an Element = Weight of an average Atom of that Element/ (1/12)x Mass of an element of C¹²

·         1 a.m.u. = 1.66x10^-24g

·         Atomic Weight = Gram Atomic Weight (GAW)

·          1 Gram Atomic Weight (GAW) of every element contains 6.023x10²³ atoms of that element.

·         No. of gram of an element = weight of element in gram/ Gram Atomic Weight (GAW) of that element

Methods of Determining Atomic Weight

                         i.     Dulong and Pettits Method: 

                                                                  Applicable only for solid elements except Be, B, C, Si.

·      Atomic Weight  x Specific Heat = 6.4 (app.)

·      Atomic Weight  (app.) = 6.4/ Specific Heat (in Calories)

·      Exact Atomic Weight = Equivalent Weight x Valency

·      Valency = App. Atomic Weight / Equivalent Weight

                        ii.     Vapour Density Method: 

                                                              Applicable only for those elements whose chlorides are volatile.

·         Valency of the Element = Molecular Weight of Chloride / Equivalent Weight of Chloride

·         Valency of the Element = (2 x V.D. of Chloride) / (Equivalent Weight of Metal + 35.5)

Where, V.D. = Vapour Density

·         Atomic Weight = Equivalent Weight of Metal x Valency

                      iii.     Specific Heat Method: 

                                                          Applicable only for Gases.

·         Cp/Cv for monoatomic gases = 1.66

·         Cp/Cv for diatomic gases = 1.40

·         Cp/Cv for triatomic gases = 1.33

·         Atomic Weight of Gaseous Element = Molecular Weight/ Atomicity

Where, Atomicity is number of atoms present in a molecule of a gaseous element. For example atomicity of Inert Gas is 1, atomicity of Ozone is 3, atomicity of H₂ N₂ O₂ X₂ is 2, and atomicity of Sulphur is 8.

                     iv.     Volatile Chloride Formation Method:

·         Atomic Weight of the Element = Equivalent Weight (Z) x Valency (x)

                       v.     Isomorphism Method: 

                                                        This method based on law of Isomorphism. According to law of Isomorphism, “Compounds having identical crystal structure have similar constitution and chemical formula”

·         Atomic Weight = Equivalent Weight x Valency

·         Weight of Element A that combines with certain weight of other elements/Weight of Element B that combines with the same weight of other elements = Atomic Weight of A / Atomic Weight of B

Molecular Weight related Chemical Formulas

·         Molecular Weight = Weight of 1 Molecule of the Substance/ (1/12)x Weight of 1 atom of C¹²

·         Actual Weight of 1 Molecule = Molecular Weight x 1.66x10^-24g

Methods of Determining Atomic Weight

1.              Diffusion Method: 

                                          Applicable only for gases.

 ·         

Where,  r₁ & r₂ is rate of diffusion of gases and M₁ & M₂ is Molecular Weight.

2.              Vapour Density Method: 

                                                    Applicable only for gases.

·         Molecular Weight = 2 x Vapour Density

3.              Victor Mayer Method:  

                                                 Applicable only for volatile liquids and solids.

·         Molecular Weight of a substance = 22400 ml of vapour of a substance at STP

Equivalent Weight related Chemical Formulas

·         No. of Gram Equivalent Weight = Weight of the substance in gram/ Gram Equivalent Weight of the substance

·         Equivalent Weight of an Element = Atomic Weight/ Valency

·         Equivalent Weight of an Acid = Molecular Weight/ Basicity

·         Equivalent Weight of an Base = Molecular Weight/ Acidity

·         Equivalent Weight of a Salt = Formula Weight/ Total Positive or Negative Charge

·         Equivalent Weight of a Reducing Agent = Formula Weight/ No. of electrons lost per molecule or Total change in Oxidation Number

·         Equivalent Weight of an Oxidising Agent = Formula Weight/ No. of electrons gained per molecule or Total change in Oxidation Number

·         Equivalent Weight of Radicals = Formula Weight of Radical/ No. of units of Charge.....

Read More

Hydrogen and its compounds MCQs Part 21

Hydrogen And Its Compounds MCQ

MCQ-1.  Hydrogen from HCI can be prepared from :

  P
  Mg
  Hg
  Cu

MCQ-2.  Commercial hydrogen is obtained from :

  Producer gas
  Marsh gas
  Oil gas
  Coal gas

MCQ-3.  Oxygen is used to purify water since it :

  absorbs harmful UV radiations
  is reducing
  is paramagentic
  destroys viruses and bacteria

MCQ-4.  How many neutrons are there in protium ? :

  3
  1
  2
  0

MCQ-5.  Which of the following is more stable ? :

  Para hydrogen
  Both are equal
  Can not be said
  Ortho hydrogen

MCQ-6.  Which one is not an isotope of hydrogen ? :

  Ortho hydrogen
  Deuterium
  Tritium
  None of the above

MCQ-7.  Pure water can be obtained from sea water by :

  Reverse osmosis
  Plasmolysis
  Sedimentation
  Centrifugation

MCQ-8.  Which one of the following metals will not reduce water? :

  Fe
  Cu
  Li
  Ca

MCQ-9.  The maximum possible number of hydrogen bonds a water molecule can from is :

  3
  2
  4
  1

MCQ-10.  In the structure of ice , each oxygen atom is surrounded by four other oxygen atoms :

  Octahedrally
  In a square planar manner
  Tetrahedrally
  None of the above

MCQ-11.  The alum used for purifying water is :

  Chrome alum
  Ammonium alum
  Ferric alum
  Potash alum

MCQ-12.  The process used for the removal of hardness of water is :

  Serpeck
  Hoope
  Calgon
  Baeyer

MCQ-13.  The exhausted permutit is generally regenerated by percolating through it a solution of :

  Calcium chloride
  Magnesium chloride
  Potassium chloride
  Sodium chloride

MCQ-14.  When sulphur trioxide is heated with heavey water the products are :

  Deuterium sulphuric acid
  Deuterium and sulphuric acid
  Deutero-sulphuric acid
  None of the above

MCQ-15.  Heavy water is used as :

  Detergent
  Drinking water
  A moderator
  Washing water

MCQ-16.  An aqueous solution of hydrogen peroxide is :

  Neutral
  Weakly acidic
  Strongly acidic
  Alkaline

MCQ-17.  Hydrogen peroxide is used as :

  An acid only
  An oxidant only
  A reductant only
  An oxidant , a reductant and an acid

MCQ-18.  The Low density of ice compared to water is due to :

  Dipole- dipole interactions
  Induced dipole- induced dipole interactions
  Hydrogen bonding interactions
  Dipole - induced dipole interactions

MCQ-19.  Which can't displace hydrogen from the compounds ? :

  Zn
  Fe
  Hg
  None of the above

MCQ-20.  The property of hydrogen which distinguishes it from alkali metals is :

  Its affinity for non-metals
  Its non-metallic character
  Its electropositive character
  Its reducing character

General Organic Chemistry MCQs Part 20

General Organic Chemistry MCQs

MCQ-1.  The shortest C - C bond distance is found in :

  Ethane
  Benzene
  Diamond
  Acetylene

MCQ-2.  Which of the following forces is strongest among the following ? :

  Dipole-dipole forces
  H-Bonding
  All equal
  Vander Waals forces

MCQ-3.  Which of the following free radicals is most stable ? :

  Methyl
  Secondary
  Tertiary
  Primary

MCQ-4.  Which of the following is an example of elimination reaction ? :

  Dehydration of ethanol
  Chlorination of methane
  Hydroxylation of ethylene
  Nitration of benzene

MCQ-5.  Acetaldehyde is the rearrangement product of :

  Vinyl alcohol
  Allyl alcohol
  Methyl alcohol
  All are correct

MCQ-6.  The least number of carbon atoms in alkane forming isomers is :

  3
  1
  4
  2

MCQ-7.  Diethyl ether is associated with which one of these isomers ? :

  Steroisomerism
  Methyl propionate
  Butanoic acid
  None

MCQ-8.  Number of primary and tertiary hydrogen atoms present neopentane are respectively :

  6,6
  12,0
  9,3
  5,7

MCQ-9.  Glucose and fructose are :

  Position isomers
  functional isomers
  optical isomers
  chain isomers

MCQ-10.  The least number of carbon atoms for an alkane to show stereoisomerism is :

  5
  3
  2
  4

Science Quiz: Purification and analysis of organic compounds MCQ Part 19

Purification and analysis of organic compounds MCQ

These are some of the random multiple question answers from Purification and analysis of organic compounds...

1. Anthracene is purified by which method :

  Distillation
  Sublimation
  Filtration
  Crystallisation

2.  A bottle containing two immiscible liquids. These liquids may be separated by using a :

  Separating funnel
  Vacuum distillation
  Fractionating coloumn
  Steam distillation

3.  When Lamery proposed his classifications of substances in the year 1675 the substance not know among the following was :

  Wine
  Iron
  Cane sugar
  Penicillin

4.  In laboratory, first organic compound was synthesized by_________  :

  Hennel
  Wohler
  Liebig
  Kekule

5. A mixture of oil and water is separated by which method:

  Sublimation
  Filtration
  Using separating funnel
  Fractional distillation

6. First organic compound to be synthesised was ________:

  Cane sugar
  Acetic acid
  Urea
  Methane

7.  Separation of two substance by fractional crytallisation depends upon their differences in the__________ :

  Crystalline shape
  Solubility
  Volatility
  Densities

8. Impure naphthalene is purified by which method  :

  Sublimation
  Fractional distillation
  Soxhlet extraction
  Fractional crystallization

9.  Which of the following not sublimate :

  Chlorine
  Bebzoic acid
  Camphor
  Naphthalene

10. Aniline is purified by which method:

  Extraction with a solvent
  Vacuum distillation
  Simple distillation
  Steam distillation