BSC 2010C Practice Problems For Test 1 Fall 2013 (with Katie's answers)
PLEASE NOTE THAT IT IS NOT POSSIBLE TO PROVIDE EVERY TOPIC OR AN
EXAMPLE OF EVERY TYPE OF QUESTION ON A SAMPLE TEST. SO PLEASE
USE YOUR NOTES AND BOOK AS A GUIDE FOR STUDY AND SUPPLEMENT
THAT WITH INFORMATION GIVEN IN CLASS.
1.
According to the octet rule, the distribution of electrons in a sulfur atom ( atomic
number 16) is:
a.
1,4,4
2,6,8
c.
2,8,6
d. 2,8,8
e.
6,8,2
Answer: C (2,8,6)
2 in first level, 8 in second, 6 in last
b.
2.
An atom with 15 protons will have how many electrons in its outermost orbital?
a.
1
2
c.
3
d. 5
e.
8
Answer: D (5)
15 minus 2 in first level minus 8 in second level = 5
b.
3.
If the hydroxide concentration of a solution is 10-4 , the hydrogen ion
concentration is:
10-2
b. 10-4
c.
10-8
d. 10-10
e.
10-14
Answer: D (10-10)
Difference between 10-14 and 10-4 = 10-10
a.
4.
The kingdoms whose members are multicellular are:
a. protista, monera
b. animalia, plantae, protista
c.
animalia, plantae, monera
d. animalia, plantae, fungi
e.
protista, fungi,monera
f.
none of these are correct
Answer: D (animalia, plantae, fungi)
The kingdoms animalia, plantae, and fungi are all multicellular. Algae are
the only multicellular members of protista; most are unicellular. Monera are
not multicellular
5.
The valence of an atom with five electrons is:
a. 5
b. 7
c.
3
d. 2
e.
1
Answer: A (5)
Valence means how many electrons are needed in the outer orbital. There
are 2 in the first orbital and 3 in the outer orbital here, so the atom needs 5
more electrons to be “full”
6.
A substance you tested yesterday had a pH of 2. After addition of a buffer you test
this substance again and the pH is 14. What is the change in the hydrogen ion
concentration?
a.
there are one million times more hydrogen ions
there are 109 times more hydrogen ions
c.
there are 1011 times more hydrogen ions
d. there are 11 times more hydrogen ions
e.
none of these answers are correct
f.
more than one of these answers is correct
Answer: E (none of the above)
There are 1012 (one trillion) times more hydrogen ions
b.
7.
A substance has a hydroxide concentration of .000001M. What is the pH?
a.
6
7
c.
5
d. 8
Answer: D (8)
.000001 M = 1x10-6 M OH- = 6 pOH
b.
8.
If a fluorine atom has an atomic weight of 16 and another has an atomic weight of
18 then these atoms are:
a.
b.
c.
d.
e.
enantiomers
isotopes
isomers
radioactive
unstable
f.
ions
more than one of the above is correct
h. None of these
Answer: B (isotopes)
If their total weights are different, then they must have a different number of
neutrons; thus, these are isotopes
g.
9.
Cations and anions would be most frequently associated with which of the
following:
a.
polar covalent bonds
van der waals forces
c.
ionic bonds
d. nonpolar covalent bonds
e.
more than one of the above is correct
Answer: C (ionic bonds)
Says it in the names “cation” and “anion”
b.
10.
What is the pH of a solution with a [H+] of 1x10-4 ?
a.
2
4
c.
–2
d. –4
e.
10
Answer: B (4)
1x10-4 M = 4 pH – Be sure to make sure it says “hydrogen” concentration
when doing pH, not hydroxide
b.
11.
The cohesiveness of water molecules is due to:
a.
hydrogen bonds
polar covalent bonds
c.
nonpolar covalent bonds
d. ionic bonds
e.
hydrophobic interactions
Answer: A (hydrogen bonds)
The four properties of water are due to hydrogen bonds
b.
12.
The partial polarity of water molecules:
a.
b.
c.
d.
e.
promotes formation of hydrogen bonds
helps water dissolve nonpolar solutes
lowers heat of vaporization
none of these choices is correct
more than one of the choices is correct
Answer: A (promotes formation of hydrogen bonds)
Water has a high heat of vaporization (Does it all just suddenly evaporate
into a gas at 100 C/212 F? No! It gradually boils away, absorbing a huge 550
calories per gram to turn into steam). It's also really bad at dissolving
nonpolar molecules; they're not (bi)polar enough for it (it likes the crazy
ones)
13.
A buffer:
a.
changes pH by a magnitude of 10 for each pH unit
absorbs excess OHc.
releases excess H+
d. is often a weak acid –base pair
e.
more than one of the above is correct
Answer: E (more than one is correct [C,D])
A buffer accepts and donates hydrogen ions depending on what is needed
(not hydroxide) and is often a weak acid-base pair
b.
14.
Identify the correct alternative hypothesis:
a.
CCR5 is anticipated to confer resistance to HIV on both the treated and
untreated groups
b. CCR5 is anticipated to confer resistance to HIV on a segment of the
northern European population rather than on the US population
c.
More than one of the choices is correct
d. None of the choices is correct
Answer: B (CCR5 is anticipated to confer resistance to HIV on a segment of
the northern European population rather than on the US population)
When making an alternative hypothesis, there must be a difference; you
cannot say “CCR5 is anticipated to affect both populations the same” since
that would be the null hypothesis
15.
The genus and species of the caribou is Rangifer tarandus According to
taxonomic classification system nomenclature, the next most exclusive level of
the system would be:
a.
class
family
c.
order
d. phylum
e.
none of the choices is correct
Answer: B (family)
DKPCOFGS
b.
16. Explain van der Waals forces (this one I didn’t provide you the answer for, you need
to read about it)
In nonpolar molecules, van der Waals forces keep the molecules together when
there's an uneven distribution of electrons (e.g. gecko's feet; story of the Dutch
gecko, van der Waals)
17. Please review chapters 4 and 5 in great detail. You must know and understand the
functional groups, the isomers, and the features of macromolecules. Try this problem:
What is this compound? This one also to be debated in SI)
CH3
CO
CH3
There are two methyl groups and one carbonyl group. Which compound it is
depends on its specific arrangement and shape. It could be acetone (or proponone),
which is the simplest ketone
18. What is homeostasis?
Homeostasis is the steady-state physiological condition of the body.
19. List all major types of chemical bonds and contrast each type with the others.
Covalent > ionic > hydrogen in terms of strength. In covalent bonds, atoms are
being shared. In ionic bonds, atoms are donated. Hydrogen bonds are more like
magnetic attractions; atoms are not being shared.
20. What is each of the properties of water and how do they work?
1. Cohesion – Water molecules holding onto other water molecules. Because of
cohesion, insects can float via surface tension. Also because of cohesion,
water is a liquid at room temperature and not a gas.
2. Adhesion – Clinging of water to a different substance (as seen in the
meniscus in lab).
3. Surface tension – Caused by cohesion. Level of difficulty involved in
breaking or stretching the surface of a liquid.
4. High specific heat (aka ability to moderate temperature) – Water is very
good at holding a constant temperature. Water absorbs heat from warmer
air and releases stored heat to cooler air with only slight changes in its own
temperature.
Other properties:
5. Expands upon freezing – Ice/solid water floats on top of liquid water because
hydrogen bonds in ice are more “ordered” and spaced out in crystal shapes,
making ice less dense.
6. Universal solvent (aka high polarity) – Water is a versatile solvent due to its
polarity and how it makes hydrogen bonds easily. Salt, for example, dissolves
in water. Water molecules surround the salt molecules and separate the Na+
from the Cl- by forming hydration shells around those two individual ions.
All of these properties are possible because of water's hydrogen bonds.
Fun fact: “According to H.H. Mitchell, Journal of Biological Chemistry 158, the
brain and heart are composed of 73% water, and the lungs are about 83% water.
The skin contains 64% water, muscles and kidneys are 79%, and even the bones are
watery: 31%.” :)
21. List every functional group we discussed.
The functional groups are certain molecules attached to organic molecules:
1. hydroxyl (alcohols)
2. carbonyl (ketones, aldehydes)
3. carboxyl (acids)
4. amino (only one with nitrogen of these; amino acids; amino acids have
both amino and carboxyl groups)
5. sulfhydryl (only one with sulfur of these; thiols)
6. phosphate (only one with phosphorous of these; ATP)
7. methyl (methylated compounds)
22. What cellular organelle occurs in both prokaryotes and eukaryotes?
Ribosomes occur in both eukaryotes and prokaryotes.
23. Review all the cellular organelles and functions, with examples, from your notes.
[Mrs. Thomas has not gone over this yet.]
24. There are ribosomes in prokaryotes.
a. true b. false
25. What is the function of the pores in the nucleus?
The nuclear pores are pathways used in the exchange of materials between the
nucleus and the cytoplasm.
26. What is the difference between a peroxisome and a ribosome?
A ribosome is like a kitchen: it makes the proteins that will be used by cells. A
peroxisome is like a container: it stores (and breaks down) fatty acids and hydrogen
peroxide.
Extra note: Structural isomers differ in shape (flat vs. branched), geometric isomers
differ in arrangement about a double bond, and enantiomers are mirror images of each
other.