Explanation:
The number of vacancies per cubic meter are calculated as follows.
= 
Putting the given values into the above formula as follows.
= 
= 
= 
= 4.706 
Thus, we can conclude that number of vacancies per cubic meter for some metal, M, is 4.706 .
Pair of compounds have the same empirical formula :C₂H₂ and C₆H₆
<h3>Further explanation</h3>
Given
Carbon compound
Required
The same empirical formula
Solution
The empirical formula is the smallest comparison of atoms of compound forming elements.
A molecular formula is a formula that shows the number of atomic elements that make up a compound.
(empirical formula) n = molecular formula
C₂H₂ and C₆H₆
Empirical formula CH
(CH)₂=C₂H₂
(CH)₆=C₆H₆
C₂H₆ and C₃H₈
C₂H₆: Empirical formula CH₃
C₃H₈: Empirical formula C₃H₈
C₂H₅OH and CH₃OH ⇒ Empirical formula
CH₃CHO: Empirical formula : CH₃CHO
CH₃COOH: Empirical formula CH₂O
The first reaction is a synthesis reaction (A+B -> AB)
It is a physical change because it could be turned back to just water or just salt through evaporation.
