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74 Chemistry: Matter and Change
Solving Problems: A Chemistry Handbook
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER 8
5. In a certain reaction, 100 kJ is required to break the reactant
bonds, and 130 kJ is released when the new product bonds
form. Is the reaction exothermic or endothermic?
8.2 Naming Molecules
Binary molecular compounds are those that contain only two different elements. In naming such compounds, given their formulas, the
rules below are followed.
1. Name the first element in the formula first, using its
element name, unchanged.
2. Name the second element, using the root of its name
and adding the suffix -ide.
3. Use the following prefixes, given the number of
each type of atom present: 1, mono-; 2, di-; 3, tri-;
4, tetra-; 5, penta-; 6, hexa-; 7, hepta-; 8, octa-;
9, nona-; and 10, deca-. Mono- is not used as a
prefix for the name of the first element.
Example Problem 8-3
Naming Binary Molecular Compounds
Name the binary molecular compound that has the formula S 2 O 7 .
The first element is named first, using the unchanged element name:
sulfur. The second element’s root is then written with the suffix -ide:
ox- plus -ide ϭ oxide. There are two sulfur atoms, so the prefix diis added. There are seven oxygen atoms, so the prefix hepta- is
added. Thus, the complete name is disulfur heptoxide. (The a in
hepta- is dropped before the vowel o in oxide.)
Practice Problems
6. Name each of the following binary molecular compounds.
a. SO 2
b. P 4 O 10
c. N 2 O 3
d. SiF 6
Naming acids A binary acid contains hydrogen and one other
element. To name such an acid, use the prefix hydro- to name the
hydrogen part of the molecule. Then to a form of the root of the second element name, add the suffix -ic. Finally, add the word acid.
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74 Chemistry: Matter and Change
Solving Problems: A Chemistry Handbook
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER 8
5. In a certain reaction, 100 kJ is required to break the reactant
bonds, and 130 kJ is released when the new product bonds
form. Is the reaction exothermic or endothermic?
8.2 Naming Molecules
Binary molecular compounds are those that contain only two different elements. In naming such compounds, given their formulas, the
rules below are followed.
1. Name the first element in the formula first, using its
element name, unchanged.
2. Name the second element, using the root of its name
and adding the suffix -ide.
3. Use the following prefixes, given the number of
each type of atom present: 1, mono-; 2, di-; 3, tri-;
4, tetra-; 5, penta-; 6, hexa-; 7, hepta-; 8, octa-;
9, nona-; and 10, deca-. Mono- is not used as a
prefix for the name of the first element.
Example Problem 8-3
Naming Binary Molecular Compounds
Name the binary molecular compound that has the formula S 2 O 7 .
The first element is named first, using the unchanged element name:
sulfur. The second element’s root is then written with the suffix -ide:
ox- plus -ide ϭ oxide. There are two sulfur atoms, so the prefix diis added. There are seven oxygen atoms, so the prefix hepta- is
added. Thus, the complete name is disulfur heptoxide. (The a in
hepta- is dropped before the vowel o in oxide.)
Practice Problems
6. Name each of the following binary molecular compounds.
a. SO 2
b. P 4 O 10
c. N 2 O 3
d. SiF 6
Naming acids A binary acid contains hydrogen and one other
element. To name such an acid, use the prefix hydro- to name the
hydrogen part of the molecule. Then to a form of the root of the second element name, add the suffix -ic. Finally, add the word acid.
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