Types of Chemical Formulas
-- The ANSWERS
There are four common types of chemical formulas.
Let's look at these four formulas for the same glucose molecule.
DEFINITIONS:
Empirical Formula -- This
is the lowest ratio of atoms in the molecule. Several different
molecules with major
differences in the other three types of formulas could all reduce to the
same
ratio of atoms and be
grouped together for that reason. Many otherwise different
carbohydrates will have the
same empirical formula.
Molecular Formula -- This is the
exact number of atoms of each type in the molecule. If there
are more than one of
a specific type of atom, subscripts are used to tell us this. In water, since
there are two
hydrogen atoms for
each oxygen atom, there is a subscript (a 2) after the
H(ydrogen) in its molecular
formula. But since water contains only one oxygen, no subscript
is needed. The absence of a subscript in a molecular formula indicates an
implied 1.
Structural Formula -- This is
the exact number of atoms placed in a two dimensional spatial
arrangement.
You not only see the number of atoms of each type, but you get to see which
are bonded to each
other. Wow!!
Molecular Model -- This is
the exact number of atoms placed in a three dimensional spatial
arrangement. The world is not flat and molecules are not flat either.
FOUR TYPES OF MOLECULES (IN SCRAMBLED ORDER)
The following are four different representations for the glucose
molecule. (unrelated to proteins)
They are not in the same order as the four definitions above.
Please resort them in the same order as the above definitions (simplest to
most complex)!!
A.
C6 H12 O6
B.
C. C
H2 O
D.
See the next box (yellow) for the correct answers!
THE ANSWERS TO THE FOUR TYPES OF MOLECULES
A is the molecular formula
B is the molecular model
C is the empirical formula
D is the structural formula
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