Calculate the energy for vacancy formation in nickel (ni), given that the equilibrium number of vacancies at 850°c (1123 k) is 4.7 × 1022 m–3. the atomic weight and density (at 850°c) for ni are, respectively, 58.69 g/mol and 8.80 g/cm3.

The energy for vacancy formation can be calculated as:

Here, is equilibrium number of vacancies, N is number of atomic sites per unit vacancies, k is Boltzmann constant, T is temperature.

Here, number of atomic sites per unit vacancies can be calculated as follows:

Here, ρ is density, is Avogadro's number and A is atomic weight.

Putting the values,

Converting to

Since, 1 =

Thus,

Now, the energy for vacancy formation at 850 °C or 1123 K can be calculated using the following equation:

Rearranging,

Putting the values,

Therefore, energy for vacancy formation in nickel is

answer: the primary difference between a hypothesis and a theory is that b hypothesis is falsifiable, but a theory has been proven to be correct. theory is an explanation of something that is happening but hypothesis is a guess of something that can happen

explanation: