Self Studies

Solid State Test - 63

Result Self Studies

Solid State Test - 63
  • Score

    -

    out of -
  • Rank

    -

    out of -
TIME Taken - -
Self Studies

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Self Studies Self Studies
Weekly Quiz Competition
  • Question 1
    1 / -0
    Ice crystallises in a hexagonal lattice. At the, low temperature, the lattice constants were a=4.53Aa = 4.53 A^{\circ} and b=7.41Ab = 7.41A^{\circ}
    How many H2OH_2O molecules are contained in a unit cell? [d(ice)=0.92g/cm3][d(ice) = 0.92 g /cm^3] 

    Solution
    The volume of the unit cell, V= a2bsin60o\displaystyle V =  a^2bsin60^o

     V= (4.53×108)2×7.41×108×0.866\displaystyle  V=  (4.53 \times 10^{-8})^2 \times 7.41 \times 10^{-8} \times 0.866                                          (1A˚=108cm)(1 \mathring {A} = 10^{-8} cm)

    V=1.317×1022cm3\displaystyle V=1.317 \times 10^{-22} \: cm^3

    The density is ρ=0.92g/cm3\rho= \displaystyle 0.92 \: g/cm^3

    NA=6.023×1023/mol,MH2O=18g/molN_A = 6.023 \times 10^{23} /mol, M_{H_2O}= 18 g/mol

    ρ=ZMVNAZ=ρVNAM\rho =\cfrac{ZM}{VN_A} \Rightarrow Z= \cfrac {\rho V N_A}{M}

    Putting all the given values in the above equation we get,

    No. of molecules per unit cell, Z=4Z=4

  • Question 2
    1 / -0
    Argon crystallises in fcc arrangement and the density of solid and liquid ArAr is 1.59 g/g / cm3cm^3 and 1.42 g/g / cm3cm^3 , respectively . The percentage of empty space in liquid ArAr is:
    Solution
    Let the volume of solid Ar=100Ar = 100 mL

    Mass of solid Ar=VAr = V × ρ=100×1.59g/cm3=159g \times \rho = 100 \times 1.59 g / cm^3 = 159 g
    Volume of liquid ArAr 

    =Massρ=159g1.4gcm3 = \dfrac {Mass}{\rho} = \dfrac {159 g}{1.4 gcm^{-3}}
    = 113.57 ml

    \because ArAr crystallises in fcc type lattice, the packing fraction = 0.74

    Actual volume occupied by ArAr

    = Packing fraction ×\times volume of solid ArAr 
    = 0.74 x 100 = 74 mL

    \therefore % empty  in liquid Ar =(113.5774)×100113.57= \dfrac {(113.57-74) \times 100}{113.57}

    = 34.84%
  • Question 3
    1 / -0
    The packing efficiency of the two-dimensional square unit cell shown below is:

    Solution
    L2=4r;L=22rL\sqrt {2} = 4r; L = 2\sqrt {2}r

    Packing fraction =Occupied areaTotal area×100= \dfrac {Occupied\ area}{Total\ area} \times 100

    =2πr2(22r)2×100=78.5= \dfrac {2\pi r^{2}}{(2\sqrt {2}r)^{2}}\times 100 = 78.5%.
  • Question 4
    1 / -0
    Which one of the following is purely a crystalline compound?
  • Question 5
    1 / -0
    How many defects exists in the arrangement of constituent particles of 7.45 g7.45\ g KClKCl?
    [K=39,Cl=35.5gm/mole][K=39,Cl=35.5gm/mole]
  • Question 6
    1 / -0
    CsBr ha cubic structure with edge length 4.4Ao4.4\overset{o}{A}. The shortest interionic distance between Cs+Cs^{+} and BrBr^- is:
    Solution

    CsBrCsBr has body centered cubic (BCC) structure. The edge length of unit cell is given by 4.4 A˚4.4 \ \mathring A

    Now, for a cube of edge aa units, the length of the diagonal is 3a\sqrt 3 a units.

    The shortest ionic distance between Cs+Cs^+ and Br=3a2Br^-= \cfrac {\sqrt 3a}{2}

    =3×4.42=3.81 A˚= \cfrac {\sqrt 3 \times 4.4}{2}= 3.81 \ \mathring A 

  • Question 7
    1 / -0
    Percentage of free space in a body centred cubic unit cell is
    Solution
    Packing fraction  =volumeoccupiedbyatomsinaunitcell volumeoftheunitcell \displaystyle  =\frac { volume\, occupied \,by\, atoms\, in \,a \,unit\, cell } {volume \,of\, the\, unit\, cell }

    For bcc,

    Packing fraction    =2×43πr3(4r3)3=3π8=0.68 \displaystyle   =\dfrac {2\times \dfrac{4}{3}\pi r^3}{\left ( \dfrac{4r}{\sqrt{3}} \right )^3}=\dfrac{\sqrt{3}\pi}{8}=0.68

    Volume occupied =68%= 68\% 

    Volume vacant =10068=32%=100 - 68 = 32\% 
  • Question 8
    1 / -0
    The packing efficiency of the face centered cubic (fcc), body centered cubic (bcc) and simple primitive cubic (pc) lattices follows the order:
    Solution

    Face centred cubic (fcc) lattice has a packing efficiency of 7474%.

    Body centred cubic (bcc) lattice has a packing efficiency of 6868%.

    Simple/ Primitive cubic (pc) lattice has a packing efficiency of 52.452.4%.

    Hence, the correct order is fcc > bcc > pc\text {fcc > bcc > pc}.

  • Question 9
    1 / -0
    ABAB has ZnSZnS type structure. What will be interionic distance between A+{A}^{+} and B{B}^{-}if lattice constant of ABAB is 200pm200pm?
    Solution
    ZnSZnS has cubic packing (ccp) crystal lattice structure which is analogous to the face-centered cubic lattice (FCC) 
    In ZnSZnS, anions form FCC and cations occupy alternate tetrahedral voids.
    Given, lattice constant == edge length of a cube =a=200 pm=a=200 \ pm
    Now, tetrahedral voids are present on the body diagonal at (14)th\left (\cfrac 14 \right)^{th} of the distance from each corner. 
    So, distance between A+A^+ and B=14×3aB^-= \cfrac 14 \times \sqrt 3 a
    =34×200 pm=503 pm= \cfrac {\sqrt 3}4 \times 200 \ pm = 50 \sqrt 3 \ pm
  • Question 10
    1 / -0
    A compound formed by elements X and Y crystallizes in the cubic structure, where X atoms are at the corners of a cube and Y atoms are at the centre of the body. The formula of the compound is?
    Solution
    X=8×18=1X=8\times \displaystyle\frac{1}{8}=1(at corner)

    Y=1×1=1Y=1\times 1=1(at body center)

    So the formula of compound is ==XY.
Self Studies
User
Question Analysis
  • Correct -

  • Wrong -

  • Skipped -

My Perfomance
  • Score

    -

    out of -
  • Rank

    -

    out of -
Re-Attempt Weekly Quiz Competition
Self Studies Get latest Exam Updates
& Study Material Alerts!
No, Thanks
Self Studies
Click on Allow to receive notifications
Allow Notification
Self Studies
Self Studies Self Studies
To enable notifications follow this 2 steps:
  • First Click on Secure Icon Self Studies
  • Second click on the toggle icon
Allow Notification
Get latest Exam Updates & FREE Study Material Alerts!
Self Studies ×
Open Now