Answer:
The separation between layers of atoms in the crystal is 164.52 pm.
Explanation:
Formula used
(Bragg's law)
Where :
n = an order of reflection (integer)
= wavelength of the beam incident X-ray
d = spacing between the layer
θ = incident angle ( angle between ray and scatter plane)
We have :
λ = 157 pm
θ = 28.5°
n = 1
d = ?
(Bragg's law)
![d=\frac{1\times 157 pm}{2\times \sin (28.5^o)}=164.52 pm](https://tex.z-dn.net/?f=d%3D%5Cfrac%7B1%5Ctimes%20157%20pm%7D%7B2%5Ctimes%20%5Csin%20%2828.5%5Eo%29%7D%3D164.52%20pm)
The separation between layers of atoms in the crystal is 164.52 pm.
Answer: C) Elements and pure compounds are homogeneous materials because they have a uniform composition throughout.
Explanation: Element is a pure substance which is composed of atoms of similar elements. Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.
Elements are compounds form homogeneous materials as they have uniform composition throughout and the components are evenly distributed throughout the material.
Mixtures are heterogeneous materials as they do not have uniform composition and the components are not evenly distributed throughout the material.
It does not consist of a single element
Hope I helped! ( Smiles )