Showing posts with label Physical Chemistry Notes. Show all posts
Showing posts with label Physical Chemistry Notes. Show all posts

Thursday, 23 August 2018

Solid State Chemistry MCQ Part 23

Solid State Chemistry MCQs

These are 20 selected MCQs from Solid State Chemistry which are very important and asked in various exams like AMU, KCET, MP CET, CBSE, Karnataka CEE, MP PMT, Kerala MEE, MP PET, AIIMS, BHU, IIT, EAMCET, NCERT, CPMT, AIEEE, CETMP, Pb PMT, AFMC.

MCQ-1.  In Solids, the constituent particles may be :

  Either of the above three

MCQ-2.  In a Crystal, atoms are located at position of the :

  Maximum P.E.
  Minimum P.E.
  Infinite P.E.
  Zero P.E.

MCQ-3.  When identical spheres in the adjacent rows have a vertical as well as horizontal alignment in a way that each sphere has 4 nearest neighbours, This type of pattern is known as :

  Cubic Close Packing
  Body Centred Cubic Packing
  Hexagonal Close Packing
  Square Close Packing

MCQ-4.  The space occupied in BCC arrangement is :

  68 %
  60.8 %
  78 %
  74 %

MCQ-5.  Which of the following have HCP structure :


MCQ-6.  Pottasium crystalizes in a BCC lattice, hence the coordination number of pottasium in pottasium metal is :


MCQ-7.  In CCP arrangement the coordination number of each sphere is :


MCQ-8.  The number of molecules in a unit structure of NaCl are :


MCQ-9.  The number of molecules of CsCl in a unit structure will be :


MCQ-10.  The total no. of 3 fold axes of symmetry in CCP arrangement is :


MCQ-11.  A match box exibits :

  Cubic Geometry
  Monoclinic Geometry
  Orthorombic Geometry
  Tetragonal Geometry

MCQ-12.  Which of the following is a molecular crystal :


MCQ-13.  Diamond is :

  Molecular Crystal
  Metallic Crystal
  Covalent Crystal
  Ionic Crystal

MCQ-14.  NaCl is a example of :

  Molecular Solid
  Metallic Solid
  Covalent Solid
  Ionic Solid

MCQ-15.  Schottky defect is found in which of the following :


MCQ-16.  Frenkel defect is found in which of the following :


MCQ-17.  Which of the following defect causes decrease in density of the crystal :

  Frenkel Defect
  Schottky Defect
  F-Centre Defect
  Interstitial Defect

MCQ-18.  Which of the following substance will conduct the current in Solid State :

  Sodium Chloride

MCQ-19.  On adding a little amount of phosphorus to silicon, We get :

  Mettalic Conductor
  n-type semiconductor
  p-type semiconductor

MCQ-20.  Semiconductors are derived from compounds of :

  p-block elements
  Transition elements

To learn more about Solid State Chemistry read our notes on Solid state chemistry...

12 Class Chapter 1- Solid State Chemistry

Solid State Chemistry

Solid: - 

        Matter which posses rigidity having definite shape &volume is called solid.

Types of solid:-

1.      Crystalline Solid :- Eg:- Metals And Non metals
2.      Amorphous Solid :- Eg:- Rubber ,Glass ,Plastic

Difference and Comparison between of characteristics

Crystalline Solid: - 

                           Contain regular arrangement having short range & as well as long range order.
Definite geometric shape, Sharpe melting point, they have definite heat fusion, they undergo clean cleavage, and they are true solid.

Amorphous Solid: - 

                         Containing irregular arrangement having short range order only, irregular shape, melting over range of temp, they do not have definite heat of fusion they undergo an irregular cut they are pseudo solid or super cooled solid.

Classification of crystalline solid:-

   1. Ionic Solid 
2. Molecular Solid
3. Covalent of network Solid
4. Metallic Solid

1. Ionic solid: - 

                     In these crystalline solids, constituent particle are positive or negative ion held together by columbic or electrostatic forces of attraction.
Eg:-NaCl, Mgo

Friday, 20 July 2018

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 :


MCQ-2.  Prefix 1018 is :


MCQ-3.  Derived SI Unit of Area is :


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 :


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 :


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 _____________ :


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


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 ________ :


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 :


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 :


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


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


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 M& 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.....

Saturday, 6 January 2018

Class 11 Chapter 6 - Thermodynamics

Class 11 Chapter 6: Thermodynamics


            A system is that part of universe in which we made observations is called system.


            All remaining part of the universe, other than system is called surroundings.
Universe = System + Surroundings

Types of System:

            The system is classified on the basis of movement of energy and matter inside or outside the system. I.e. open system, closed system and isolated system.

     1.     Open System:

A system in which exchange of matter and energy between the system and surroundings take place, is called open system.
Example:- Reaction in open beaker.

     2.     Closed System:

A system in which exchange of energy between the system and surroundings take place but there is no exchange of matter between the system and surroundings takes place, is called closed system.
Example:- Reaction in closed conducting vessel of steel.

     3.     Isolated System:

A system, in which no exchange of matter and energy between the system and surroundings take place, is called isolated system.
Example:- Reaction in isolated vessel like thermos flask.

The state of the system

            In chemistry, the state of thermodynamic system is described by the measurable or macroscopic i.e. bulk properties of the thermodynamic system.
To learn better, if someone asks, how we can describe the state of a gas?
So to answer this question, we describe the state of a gas by getting information about pressure (p), volume (V), temperature (T) and amount (n) etc. of gas.
So, these variables i.e. p, V, T are known as state variables or state functions.
Why these variables (p, V, T) are called state variables or state functions?
These variables are called state variables or state functions because their values depends only on the state of the system and do not depend on how they are reached on that point.

Internal Energy

            Sum of all energies (like chemical, electrical, mechanical etc.) of the system is called internal energy (U) of the system.
Now question is when internal energy of the system changes?
Internal energy of the system changes when,
·        Heat passes into or heat passes out of the system.
·        Work is done on the system or work is done by the system.
·        Matter enters the system or matter leaves the system.

     i.       Work

Before learning about effect of work on internal energy we first understand what is Adiabatic system.

Adiabatic system

            Adiabatic system is a system which does not allow transfer of heat through its boundary; means heat can not enters or leave the system.

Work on adiabatic system

            If 1kJ mechanical work done (case 1) on the system and 1kJ electrical work done (case 2) on the system than change in temperature is same in bath cases.
So, amount of work done on the system produces the same change of state no matter how this work was done.
            U = U2 – U1 = Wad
            U = internal energy
            U2 = internal energy at state 2 (final state)
U1 = internal energy at state 1 (initial state)
Wad = adiabatic work
Sign of Wad
a.     If Wad is positive, then work is done on the system.
b.     If Wad is negative, then work is done by the system.

      ii.     Heat

What is heat?

The exchange of energy due to difference in temperature is called heat.

If system allows exchange of heat (conducting walls of the system) then change in internal energy depends on amount of heat transfer between system and surroundings at constant volume when no work is done.
            U = q
            U = internal energy
            q = heat
            Sign of q
a.     q is positive, if heat is transferred from the surroundings to the system.
b.     q is negative, if heat is transferred from the system to surroundings.

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