X-ray diffraction studies show that Cu crystallises in face centred cubic unit cell with cell edge of 3.608 × 10-8 cm. An another experiment shows that Cu is determined to have a density of 8.92 g / cm 3. Find out the atomic mass of copper.

Question

X-ray diffraction studies show that Cu crystallises in face centred cubic unit cell with cell edge of 3.608 × 10-8 cm. An another experiment shows that Cu is determined to have a density of 8.92 g / cm 3. Find out the atomic mass of copper. (A) 61.3 u (B) 62.3 u (C) 63.1 u (D) 64.1 u

Tardigrade Admin · Accepted Answer

In case of fcc lattice, number of atoms per unit cell, Z=4. We know that, M=(d NA a3/Z) ∴ M=(8.92 g / cm 3 × 6.022 × 1023 atom mol -1×(3.608 × 10-8 cm )3/4 text atom )=63.1 g / mol

Q. $X$ -ray diffraction studies show that $C u$ crystallises in face centred cubic unit cell with cell edge of $3.608 \times 1 0^{- 8} c m$ . An another experiment shows that $C u$ is determined to have a density of $8.92 g / c m^{3}$ . Find out the atomic mass of copper.

$61.3 u$

$62.3 u$

$63.1 u$

$64.1 u$

In case of $f cc$ lattice, number of atoms per unit cell, $Z = 4$ .
We know that, $M = \frac{d N _{A} a ^{3}}{Z}$
$∴ M = \frac{8.92 g / c m ^{3} \times 6.022 \times 1 0 ^{23} a t o m m o l ^{- 1} \times ( 3.608 \times 1 0 ^{- 8} c m ) ^{3}}{4 atom} = 63.1 g / m o l$

Q. X-ray diffraction studies show that Cu crystallises in face centred cubic unit cell with cell edge of 3.608×10−8cm. An another experiment shows that Cu is determined to have a density of 8.92g/cm3. Find out the atomic mass of copper.

61.3u

62.3u

63.1u

64.1u