Answer:
a) 149 kJ/mol, b) 6.11*10^-11 m^2/s ,c) 2.76*10^-16 m^2/s
Explanation:
Diffusion is governed by Arrhenius equation

I will be using R in the equation instead of k_b as the problem asks for molar activation energy
I will be using

and
°C + 273 = K
here, adjust your precision as neccessary
Since we got 2 difusion coefficients at 2 temperatures alredy, we can simply turn these into 2 linear equations to solve for a) and b) simply by taking logarithm
So:

and

You might notice that these equations have the form of

You can solve this equation system easily using calculator, and you will eventually get

After you got those 2 parameters, the rest is easy, you can just plug them all including the given temperature of 1180°C into the Arrhenius equation

And you should get D = 2.76*10^-16 m^/s as an answer for c)
Answer:
a)5.28 Å , b)3.73 Å , c)3.048 Å
Explanation:
the atoms are situated only at the corners of cube.Each and every atom in simple cubic primitive at the corner is shared with 8 adjacent unit cells.
Therefore, a particular unit cell consist only 1/8th part of an atom.
The lattice constant of a simple cubic primitive cell is 5.28 Å
We know formula of distance,
d = 
a)(100)
a=5.28 Å
Distance =
=5.28 Å
b)(110)
Distance =
= 3.73 Å
c)(111)
Distance=
= 3.048 Å
Answer: precision
Explanation: Because accuracy is where you keep on getting it right but precision is where you get closer and closer
Less, if it’s too big: hard to control and maneuverability for shooting wouldn’t be that good. a smaller wheelchair allows for faster movement and control, along with easier shooting and upper body movement