. Gold crystallises in fcc unit cell having edge length is 408 pm. calculate the density of gold (given molar mass of gold is 197gm/mol)
Answers
Answer:
Reena was out from her home when
strong/high speed winds blow and an
umbrella she held upright at time gets
upturned due to:
(a) Due to high speed wind passing through
umbrella creates low pressure.
(b) Due to heavy rainfall over the umbrella
(c) Due to poor quality of umbrella.
(d) None of the above.
Answer:
Mark me as brainliest
Explanation:
For an FCC crystal, atoms are in contact along the diagonal of the unit cell.
4r=
2
a, where a is the edge length of unit cell and r is the radius of atom.
Substituting values in the above expression, we get
r=
4
2
×407
=143.9 pm
Number of atoms per unit cell (FCC) =4
Mass of 1 unit cell =197×4=788amu=1.66×10
−27
×788kg=1.30808×10
−24
kg
Volume of 1 unit cell =(407×10
−12
)
3
m
3
=6.741×10
−29
m
3
=2.824×10
−28
m
3
Density=
6.741×10
−29
1.30808×10
−24
=19404.83kg/m
3
=19.4g/cm
3