The formula of density is mass / volume
This means that
- high mass, low volume = high density
- high mass, high volume = so-so
- low mass, high volume = low density
From the graph shown,
D has the lowest density because it has low mass yet high volume.
Answer:
B. The number of atoms in a molecular formula is always greater than the number of atoms in an empirical formula.
Explanation:
It is not always true that the number of atoms in a molecular formula is always greater than the number of atoms in an empirical formula.
The chemical formulae of a compound are of two main types;
- The empirical formula is that which expresses the composition of a compound in the simplest whole number ratio.
- The molecular formula shows the actual ratio of the atoms in a compound.
Sometimes the number of atoms in the molecular and empirical formula can be the same.
Also, the number of atoms in the molecular formula is always greater than that of the empirical formula when they are not the same.
Ionic compounds are formed between oppositely charged ions.
A binary ionic compound is composed of ions of two different elements - one of which is a positive ion(metal), and the other is negative ion (nonmetal).
To write the empirical formula of binary ionic compound we must remember that one ion should be positive and other ion should be negative, then only the correct formula should be written. To write the empirical formula the charges of opposite ions should be criss-crossed.
First empirical formula of binary ionic compound is written between
First Formula would be 
Second empirical formula is between 
Second Formula would be 
Note : When the subscript are same they get cancel out, so
would be written as 
Third empirical formula is between 
Third Formula would be :
Forth empirical formula is between 
Forth Formula would be :
or 
Note- The subscript will be simplified and the formula will be written as
.
The empirical formula of four binary ionic compounds are : 