Answer:
Therefore the equilibrium number of vacancies per unit cubic meter =2.34×10²⁴ vacancies/ mole
Explanation:
The equilibrium number of of vacancies is denoted by  .
.
It is depends on
- total no. of atomic number(N)
- energy required for vacancy
- Boltzmann's constant (k)= 8.62×10⁻⁵ev K⁻¹
- temperature (T).

To find  equilibrium number of of vacancies we have find N.

Here ρ= 8.45 g/cm³  =8.45 ×10⁶m³
 = Avogadro Number = 6.023×10²³
= Avogadro Number = 6.023×10²³
 = 63.5 g/mole
= 63.5 g/mole

     g/mole
 g/mole
Here  =0.9 ev/atom , T= 1000k
=0.9 ev/atom , T= 1000k
Therefore the equilibrium number of vacancies per unit cubic meter,

    =2.34×10²⁴ vacancies/ mole
 
        
             
        
        
        
The answer to this question would be: alkaline earth metal
Alkali earth metal is the second column group of the periodic table. In this group, the element has 2 extra electrons in their outer cells. That is why most of this metal has 2+ charge. 
Their neighbor is the alkali metal which was the first column of the periodic table. The name is similar so don't confused and mix them each other.
        
             
        
        
        
Isn't this a math problem?
If it is the the answer should be 102.
10 decimeters=1 meter
27x10=270 
270-168=102
        
             
        
        
        
<u>Answer:</u> The true statement is iron can reduce  to gold metal
 to gold metal
<u>Explanation:</u>
Single displacement reaction is defined as the reaction in which more reactive element displaces a less reactive element from its chemical reaction.
The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.

Metal A is more reactive than metal B.
We are given:
Iron can reduce copper, silver can reduce gold, sodium can reduce iron and copper can reduce silver metal.
The increasing order of reactivity thus follows:

where, sodium is most reactive and gold is least reactive
For the given options:
<u>Option 1:</u>  Copper cannot easily reduce sodium ion to sodium metal because it is less reactive.

<u>Option 2:</u>  Iron cant easily reduce gold ion to gold metal because it is more reactive.

<u>Option 3:</u>  Silver cannot easily reduce iron ion to iron metal because it is less reactive.

Hence, the true statement is iron can reduce  to gold metal
 to gold metal
 
        
             
        
        
        
Answer:
Avogadro's number is the number of particles in one mole of anything. In this context, it is the number of atoms in one mole of an element. It's easy to find the mass of a single atom using Avogadro's number. Simply divide the relative atomic mass of the element by Avogadro's number to get the answer in grams.