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)

The separation between layers of atoms in the crystal is 164.52 pm.
Answer:
Combination reaction
Explanation:
In Chemistry, elements and compounds are involved in a process called chemical reactions, which are of different types namely: combination, decomposition, double replacement, combustion etc. A combination reaction is that reaction in which two or more substances called the REACTANTS combine together to form a single new substance called the PRODUCT.
In this case, a reaction is depicted as follows:
2SO2(g) + O2(g) --> 2SO3(g)
In this reaction, compound SO2 combines chemically with element O2 to form a single new compound SO3. Hence, this is a type of COMBINATION REACTION.