Chemistry Reference
In-Depth Information
9. [36]—Each molecule of C
6
H
12
O
6
contains 12 hydrogen atoms, so 3
molecules contain 3 x 12, or 36 hydrogen atoms.
10. [18]—Each molecule of C
6
H
12
O
6
contains 6 oxygen atoms, so 3 molecules
contain 3 x 6, or 18 oxygen atoms.
Chapter 5 Examination
1. [e. formula mass]—Although the calculation is identical to the calculation
for molecular mass, we use this term for ionic compounds.
2. [b. binary compound]—Just as a bicycle has two wheels, a binary compound
has two elements.
3. [g. empirical formula]—We reduce the coefficients of a molecular formula
to get the empirical formula.
4. [c. molecular formula]—A compound that has a molecular formula of C
2
H
6
actually exits as molecules made with 2 atoms of carbon and 6 atoms of
hydrogen.
5. [a. oxidation number]—Oxidation numbers can be used to determine
chemical formulas.
6. [F. BaSO
3
]—The polyatomic ion called “sulfite” contains one less oxygen
atom than “sulfate.”
7. [E. BaSO
4
]—The “ates” contain more oxygen than the “ites.”
8. [C. Cu
2
O]—The Roman numeral gives the oxidation number of the metal.
When copper has an oxidation number of +1, it takes two atoms of it to
balance out the oxygen, with an oxidation number of -2.
9. [D. CuO]—When copper has an oxidation number of +2, it takes one atom
of it to balance out the oxygen, with an oxidation number of -2.
10. [A. FeCl
3
]—When iron has an oxidation number of +3, it takes three
atoms of chloride (Cl
-
) to create a neutral compound.
11. [B. FeCl
2
]—When iron has an oxidation number of +2, it takes two atoms
of chloride (Cl
-
) to create a neutral compound.
12. [G. LiNO
3
]—Remember, the “ates” have more oxygen than the “ites”, so
the nitrate is the polyatomic ion with more oxygen.
13. [H. LiNO
2
]—The polyatomic ion called nitrite contains one less oxygen
atom than nitrate.
14. [A. (NH
4
)
2
CO
3
]—Ammonium, NH
4
+
, with an oxidation number of +1 must
combine with the carbonate, CO
3
2-
, in a 2:1 ratio. We need to put the
ammonium ion in parentheses, because it is a polyatomic ion, and we need
more than one of them.
