Nickel metal has a cubic close packed structure with a face centered cubic cell

Question

Nickel metal has a cubic close packed structure with a face centered cubic cell

please help with questions 6-8

Nickel metal has a cubic close-packed structure with a face-centered cubic unit cell. The length of the cubic unit cell edge is 3.53 A. Use this information to calculate (a) the atomic radius of a nickel atom and (b) the density of nickel metal. Draw the correct structure or write the correct name for the compound below. a. 4-ethylheptane b. 2, 2, 4-trimethylhexane c. 1, 3-dichloro-2-butene d. CH_3-CH_2-CH_2-CH-CH_3 e. CH_3-CH_2-CH_2-CH_2-C-CH_2 CH-CH_3 f. HC C-CH_2-C-CH_3 Explain the difference between a substitution and an addition reaction for alkenes.

Explanation / Answer

6)

a)

for FCC lattice,

length of face diagonal = 4*r

sqrt(a^2 + a^2) = 4*r

a*sqrt(2) = 4*r

3.53*sqrt(2) = 4*r

r = 1.25 Ao

Answer: 1.25 Ao

b)

density,

d = (Z*M)/(a^3*NA)

where d is density in g/cm^3

Z is 1 for cubic lattice, 2 for bcc and 4 for fcc

a is edge length in cm = 3.53*10^-8 cm

M is molar mass in g/mol = 58.7 g/mol

NA is Avogadro’s constant

d = (Z*M)/(a^3*NA)

= (4*58.7)/((3.53*10^-8)^3 * 6.022*10^23)

   = 8.86 g/cm^3

Answer: 8.86 g/cm^3

I am allowed to answer only 1 question at a time

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