Transcript Molecular Formulas

Molecular Formulas
A molecule is a neutral group of atoms united by
covalent bonds. A substance that is made of
molecules is called a molecular substance. To
describe the composition of a molecular
compound, chemists often use a molecular
formula. A molecular formula tells you how
many atoms are in a single molecule of the
compound.
What is a subscript?
If a molecule contains more than one atom of a
particular element, this quantity is indicated
using a subscript after the chemical symbol.
NH3
Subscript
GLUCOSE
EXAMPLE: The molecular formula for glucose
(a simple type of sugar):
C6H12O6
6 atoms of carbon
12 atoms of hydrogen
6 atoms of oxygen
Molecular Structure for Glucose
SAMPLE PROBLEMS:
1. What elements are in the following
compound: Lithium acetate (LiC2H3O2)?
a. Lithium
b. Carbon
c. Hydrogen
d. Oxygen
LiC2H3O2
2. How many atoms of each element are in the
compound above?
Li = 1
C=2
H=3
O=2
3. How many total # of atoms are in the
following compound: Ammonium phosphate
((NH4)3PO4)?
N=3
H = 12
P=1
O=4
4. Write the chemical formula for the following
compound.
1 atom of gold and 3 atoms of chlorine
Au
AuCl3
Cl
Cl
Cl
Practice Problems
Part A
5.
2 atoms of hydrogen, 1 atom of sulfur, and 4 atoms of oxygen
H2SO4
Part B
1.
ZnS
Zinc
Sulfur
Part C
1.
Glucose: C6H12O6
Carbon = 6
Hydrogen = 12
Oxygen = 6
Number of Atoms in a Formula
18.
Mg(C2H3O2)2
Mg = 1
C =4
H =6
O=4
15 atoms
Great Combinations
4. Phosphorus pentoxide
O
O
P
O
O
P
O