Sunday
December 21, 2014

Homework Help: Chemistry

Posted by Amanda on Friday, August 26, 2011 at 8:40am.

Can somebody check my answers? I Failed this test one time already. I do not want to fail it again.

1. When a pair of electrons is shared between two atoms, a
covalent bond is said to have formed. Most often, the pair
is formed

A. by excess valence electrons.
B. as one atom contributes both electrons.
C. as each atom contributes one electron. (MY ANSWER)
D. as one atom “steals” two electrons from the other.

2. A molecule of water is composed of two atoms of hydrogen and
one atom of oxygen (H2O). If the atomic mass number of hydrogen
is 1 and the molecular mass of water is 18, the atomic
mass of oxygen must be

A. 36.
B. 16. (MY ANSWER)
C. 18.
D. 14.

3. Physical properties of matter include all of the following except
A. reactivity. (MY ANSWER)
B. odor.
C. density.
D. solubility.

4. Regarding phases of matter, which statement is true?

A. The kinetic, but not the potential, energy of a gas is higher than that of a liquid.

B. The kinetic and potential energy of a gas are higher than those of a liquid.(MY ANSWER)

C. The potential, but not the kinetic, energy of a gas is higher than that of a liquid.

D. The potential energy of a gas is always lower than that of a liquid.

5. The forces that will establish chemical bonds between atoms result from the interaction of
attractive and repulsive forces between

A. protons and electrons.
B. electrons.
C. electrons in the valence shell. (MY ANSWER)
D. protons, but only when electrons are lost.

6. An atom is to an element as a compound is to a
A. substance.
B. molecule. (MY ANSWER)
C. chemical.
D. mass.

7. For the quantum number called _______, a value called _______ relates to a clockwise
motion of a given electron.
A. orbital, shape
B. electron spin, “up” (MY ANSWER)
C. orbital, sublevel
D. electron spin, “down”

8. The symbol for a boron isotope is B. What is the mass number of this isotope?
A. 5
B. 6
C. 11 (MY ANSWER)
D. 16

9. The symbol for a boron isotope is B. How many neutrons does this isotope have?
A. 5
B. 6 (MY ANSWER)
C. 11
D. 16

10. For the neon atom, the total number of electrons that can be found in the second principal
energy level is
A. 4.
B. 6.
C. 8. (MY ANSWER)
D. 10.

11. Which one of the following statements is true?

A. Fluorine, having seven valence electrons, can’t form a polar covalent bond.

B. Hydrogen can’t attain a noble element configuration because it has only one electron.

C. Fluorine, having four valence electrons, must form a nonpolar covalent bond.

D. Hydrogen can attain a noble gas structure by sharing only two electrons. (MY ANSWER)

12. The kilopascal is to pressure as the Kelvin scale is to the average _______ energy of
any substance.

A. kinetic (MY ANSWER)
B. potential
C. volume
D. mass

13. The most probable distance of an electron from an atom’s nucleus, expressed in whole
numbers, refers specifically to

A. the principal quantum number.
B. electron spin.
C. the Pauli exclusion principle. (MY ANSWER)
D. the sum of an atom’s sublevels.

14. We can describe _______ energy as the energy a body has depending on its position with
relationship to another body.

A. heat
B. kinetic
C. potential (MY ANSWER)
D. system

15. “Its bonds are strong, and its more or less nonmobile nuclei are surrounded by a sea of
mobile electrons.” This sentence best expresses _______ bonds.

A. metallic (MY ANSWER)
B. coordinate covalent
C. ionic
D. multiple covalent

16. According to Hund’s rule, electrons fill sublevels one electron at a time, and all _______
electrons around a given atom will have

A. paired, the same spin.
B. unpaired, the same spin.
C. paired, a single negative charge.
D. unpaired, equal valence energy. (MY ANSWER)

17. Looking at the Periodic Table, we find that in every vertical group, electronegativity
_______ as we move down and as atomic number increases. At the same time, moving
horizontally across a row of the table, we find that electronegativity _______ as we move
from left to right.

A. decreases, increases
B. decreases, decreases
C. increases, decreases (MY ANSWER)
D. increases, increases

18. If two atoms form a molecule, the approximated distance between the nuclei of the two
atoms is called the

A. covalent atomic radius.
B. bond length. (MY ANSWER)
C. bond length less the covalent atomic radius.
D. effective bond radius.

19. Expressed as joules per gram degree, _______ heat capacity is a quantity necessary to
raise the temperature of one gram of any substance by one degree Celsius.

A. Kelvin
B. mass
C. differential (MY ANSWER)
D. specific

20. As determined by the work of physicist Niels Bohr, an atom emits energy when one of its
electrons falls from a higher to a lower energy level. Following from this observation, the
Bohr model also proposes that the difference between the two energy levels in such a
case determines the

A. color of the electron.
B. frequency of the emitted radiation.
C. instability of the atom’s nucleus.
D. mass of the emitted radiation. (MY ANSWER)

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