Chemistry Reference
In-Depth Information
7.
[B.]—A double covalent bond is represented by two pairs of shared
electrons, found between two atoms. Answer B shows the dot diagram for
the compound called ethane.
8.
[D.]—In order to form a coordinate covalent bond, one atom must provide
a pair of electrons. Of the choices, only the sulfur (IV) oxide has a pair of
unshared electrons that can be used for a coordinate covalent bonding site.
Lesson 4-4 Review
1.
[B.]—A hydrocarbon is a compound that is composed of hydrogen and
carbon, so that rules out images E and F. A saturated hydrocarbon only has
single covalent bonds. Image B, representing the compound methane,
shows the only saturated hydrocarbon.
2.
[C.]—The prefix “pro-” indicates that the compound that we are looking for
contains three atoms of carbon, as in images A and C. The suffix “-ene”
indicates that the compound has a double bond like image C.
3.
[ethyne]—We use the prefix “eth-” for hydrocarbons with two atoms of
carbon, and the suffix “-yne” for hydrocarbons with a triple bond.
4.
[C.]—The alkenes are hydrocarbons that contain a double bond, as in the
compound shown in image C. Carbon dioxide has double bonds, but it is not
a hydrocarbon.
5.
[B.]—The general formula C
n
H
2n+2
indicates that if you take the number of
carbon atoms and multiply by 2 and then add 2, you will get the number of
hydrogen atoms in the compound. Image B shows the compound methane,
which follows this general formula. Methane contains one carbon atom and
(2(1) + 2 = 4) 4 hydrogen atoms.
6.
[propyne]—We use the prefix “prop” to indicate the three carbon atoms
and the suffix “yne” to indicate the triple bond.
Lesson 4-5 Review
1.
[B.]—Compounds with the general formula XY
4
, such as CH
4
and CCl
4
,
tend to form the tetrahedral shape.
2.
[unshared electrons]—The unshared electrons that the nitrogen atom has
will repel the electron pairs in the compound further, resulting in a
pyramidal shape.
3.
[bent]—Water is the classic example of a bent molecule. The unshared
electrons in the oxygen atom's valence shell are thought to repel the shared
pairs of electrons enough to bend the molecule.
4.
[D.]—The nuclei of the atoms in the molecule of carbon dioxide are
arranged in a line.
