CHEM 210 Module 2 Exam Newest
1. a higher melting or boiling point indicates the molecule has: stronger
inter- molecular forces.
2. What is the shape of water?: Bent. The bond angle is 104.5 degrees.
3. What is autoionization, and how is it important for water?: Autoionization
is the ability of a compound to react with itself to form ions. One water
molecule reacts with a second molecule to form two ions: H3O+ and
OH-. These ions exist in small amounts in pure water and influence the
chemistry of water.
4. Name the three non-covalent forces discussed in this module.: 1. Dipole-
di- pole forces, 2. Hydrogen bonding, and 3. London dispersion forces
5. What type of non-covalent interaction is known as the strongest dipole-
di- pole force?: hydrogen bonds
6. How does the strength of London forces change with increasing
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, molecular weight? Explain briefly.: As molecular weight increase, the
strength of London forces also increase. This is due to the increased
number of electrons in larger mol- ecules. The larger number of
electrons creates the potential of stronger temporary dipoles.
7. What is the concentration, in M, of water as a pure liquid?: 55.5 M
8. Define Keq and Kw.: Keq is the equilibrium constant. Numerically, it
is equal to the concentrations of equilibrium products (in M)
multiplied together over the concentration of equilibrium reactants
multiplied together.
Kw is called the ion product. It is, essentially, the Keq for water that is
equal to 1.0 x 10-14; the formula is:
9. Identify the acid, conjugate base, and proton in the following reaction.
HCOOH --> H+ + HCOO-: HCOOH weak acid
H+ proton
HCOO- conjugate base
10.A buffer system has a pKa of 8.5. What is its effective buffering range?:
7.5 to 9.5
11.Weak acid A has a pKa of 3.2, while weak acid B has a pKa of 5.6. Is
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1. a higher melting or boiling point indicates the molecule has: stronger
inter- molecular forces.
2. What is the shape of water?: Bent. The bond angle is 104.5 degrees.
3. What is autoionization, and how is it important for water?: Autoionization
is the ability of a compound to react with itself to form ions. One water
molecule reacts with a second molecule to form two ions: H3O+ and
OH-. These ions exist in small amounts in pure water and influence the
chemistry of water.
4. Name the three non-covalent forces discussed in this module.: 1. Dipole-
di- pole forces, 2. Hydrogen bonding, and 3. London dispersion forces
5. What type of non-covalent interaction is known as the strongest dipole-
di- pole force?: hydrogen bonds
6. How does the strength of London forces change with increasing
1/4
, molecular weight? Explain briefly.: As molecular weight increase, the
strength of London forces also increase. This is due to the increased
number of electrons in larger mol- ecules. The larger number of
electrons creates the potential of stronger temporary dipoles.
7. What is the concentration, in M, of water as a pure liquid?: 55.5 M
8. Define Keq and Kw.: Keq is the equilibrium constant. Numerically, it
is equal to the concentrations of equilibrium products (in M)
multiplied together over the concentration of equilibrium reactants
multiplied together.
Kw is called the ion product. It is, essentially, the Keq for water that is
equal to 1.0 x 10-14; the formula is:
9. Identify the acid, conjugate base, and proton in the following reaction.
HCOOH --> H+ + HCOO-: HCOOH weak acid
H+ proton
HCOO- conjugate base
10.A buffer system has a pKa of 8.5. What is its effective buffering range?:
7.5 to 9.5
11.Weak acid A has a pKa of 3.2, while weak acid B has a pKa of 5.6. Is
2/4
