SBIOAC TEST # 1 The Chemistry of Life
Name:
. Date: .
Attempt
all questions as no marks will be deducted for incorrect responses. Each question is worth one mark unless
otherwise stated. TOTAL
1. Name three themes in biology. (3)
life is
hierarchical (each level builds on the preceding level); each level may exhibit
emergent properties; the cell is the basic unit of life; organisms are open
systems that interact with their environment; the continuity of life is based
on heritable information in DNA; structure and function are correlated at all
levels of organization; living organisms exhibit homeostasis
2. Which of the following is the most inclusive?
a. community
b. population
c. ecosystem
d. biome
3. A community and its physical environment
constitute
a. a population
b. the
biosphere
c. an ecosystem
d. an organ
system
4. The scientific name of an organism consists of
which two levels of classification?
Genus and species
5. Which term
is defined as all the chemical reactions that are required to sustain life?
a. metabolism
b. catabolism
c. anabolism
d. digestion
6. Define isotope.
Isotopes are atoms of the same element that differ in the number
of neutrons.
7.
Which subatomic particle participates in chemical reactions? electron .
8. A positively charged ion has .
a. more protons than
electrons c. equal numbers of neutrons and electrons
b. more electrons than protons d. equal numbers of electrons and protons
9. Ions are
a. charged atoms or molecules that have gained
or lost electrons.
b. radioactive isotopes that give off alpha,
beta, or gamma radiation.
c. electrically neutral fragments of a molecule
that has been split apart.
d. none of the above
10. Chlorine,
with an atomic number of 17, would be expected to have ___ electrons in its outer shell.
a. one
b. seven (it’s in group 17 or VIIA)
c. ten
d. seventeen
11. Which of the following atoms is least likely to react chemically?
a. carbon
b.
hydrogen
c.
sodium
d.
helium (it’s a noble gas)
12. The
maximum number of electrons in the shell closest to the nucleus is
a.
one.
b. two.
c. four.
d. eight.
13. The only
atom that has a nucleus with no neutrons is
a.
oxygen. c. carbon.
b.
hydrogen. d.
helium.
14. What kind of bond exists between O and H, as in a molecule of water?
a. ionic
b. nonpolar covalent
c. polar
covalent (key words are “in a molecule of water”)
d.
hydrogen
15. Name all the levels of
classification from LARGEST to SMALLEST .
Kingdom Phylum Class Order Family Genus Species
16. When an atom with one electron in the
outer shell loses it, the atom becomes
a. an
isotope.
b. a positively
charged ion (like all good little alkaline metals).
c. a
negatively charged atom.
d. radioactive.
17. Which is
true of organisms that are classified in the same genus?
a. They
must be in the same phylum, but may be of different species.
b. They must be of the same species, but may be in different phyla.
c. They must be in the same phylum, but may be in different kingdoms.
d. They must be in the same kingdom, but may be in different phyla.
18. When the rate of conversion from products to
reactants and from reactants to products is in balance (a steady state), the
reaction is said to be at equilibrium
.
19. A covalent bond is likely to be polar if .
a. one of
the atoms sharing electrons is much more electronegative.
b. it is between two metals.
c. it is between two atoms that are
both very strong electron acceptors.
d. the two atoms sharing electrons are of the same element.
20. The nucleus of an atom has .
a. negative
charge c. a neutral
charge
b. a positive charge d.
none of the above
21. Some groups of elements react chemically in similar ways. For
example, the chemistry of sodium and the chemistry of lithium are similar, as
are the chemistries of chlorine and iodine. These similar chemistries are
caused when different elements have similar .
a. atomic
size
b. number of valence electrons
c. atomic
masses
d. numbers
of electrons
22. In a lake polluted with acid rain, the concentration
of H+ is 10-4 M.
What is the pH of the water?
The pH is 4 (take the negative log of the concentration)
23. A substance that resists changes in pH is
called a(n) .
a. acid
b. solvent
c. buffer
d. base
24. Substance A is found to have a pH of 3; substance B has a pH of 7.
a. A
is 4X more acidic than B
b. B
is 4X more acidic than A
c. A is 10 000 X more acidic than B
d. B
is 10 000 X more acidic than A
25. A molecule
that has all non-polar covalent bonds would be .
a. acidic
b. basic
(alkaline)
c. hydrophilic
d. hydrophobic
26. Identify each pair of isomers as structural,
geometric or stereoisomers. (3)
structural .
stereoisomer .
geometric
(there are double bonds in the middle)
27. Adding a base
tends to __________ of a solution.
a. lower hydrogen ion concentration and lower the pH
b.
lower hydrogen ion concentration and increase the pH
c. increase hydrogen ion concentration and lower pH
d. increase hydrogen ion concentration and increase pH
28. The
partial charges on a water molecule occur because of .
a. covalent bonding.
b. the transfer of an electron from hydrogen to oxygen.
c.
unequal sharing of electrons between hydrogen and oxygen.
d. it contains two different types of atoms
29. Water plays many roles in cells. Which of the
following is NOT a property of water?
a. It displays high surface tension.
b. It possesses a high heat capacity.
c. It dissociates
completely into H+ and
d. It serves as an excellent solvent for many substances.
BONUS
For each event listed below, select the
property of water responsible from the list (1/2 point each to maximum of 2.5
marks)
You
may shiver on a very hot day when you leave an outdoor pool C .
Ionic
and polar substances dissolve in water
D
.
A
water strider can stand on the surface of water F .
An
iceberg floats B .
A.
adhesion
B.
denser as liquid than solid
C.
evaporative coolant
D.
polar molecules
E.
specific heat capacity
F.
cohesion