CHEM 105 FINAL EXAM PORTAGE LEARNING
LATEST ACTUAL EXAM QUESTIONS AND
CORRECT DETAILED ANSWERS (CORRECT
VERIFIED ANSWERS) NEWEST UPDATED
VERSION |ALREADY GRADED A+
Beginning of SI Units
Units can be length (meters), volume (liters), and mass (grams) - ANSWER: Yay
Prefixes (Large to small)
Mega - ANSWER: M
1 X 10^6 m = 1 Mm
One million meters in one Megameter
Kilo - ANSWER: k
1 x 10^3 m = 1 Km
1000 meters in 1 Kilometer
centi - ANSWER: c
10^2 cm = 1 m
100 centimeters in 1 meter
milli - ANSWER: m
10^3 mm = 1 m
1000 millimeters in 1 meter
micro - ANSWER: u
10^6 um = 1 m
1 million micrometers in 1 meter
nano - ANSWER: n
10^9 nm = 1 m
1 Billion nanometers in 1 meter
Angstrom - ANSWER: A
10^10 A = 1 m
10 billion A in 1 meter
pico
End of Si Units - ANSWER: p
10^12 pm = 1 m
,1 trillion picometers in 1 meter
What is the relationship between melting point and freezing point? - ANSWER: They
occur at the same temperature for a substance.
Why are solids and liquids denser than gases? - ANSWER: Particles are in direct
contact, more per unit of volume (mass).
What happens to the average speed of atoms as the temperature of a substance
increases? - ANSWER: The average speed of atoms increases.
Which remains solid at higher temperatures: argon or neon? - ANSWER: Argon
remains solid at higher temperatures than neon.
Gas phase - ANSWER: Molecules far apart and move a lot.
Liquid phase - ANSWER: Molecules in close contact and slide past each other.
Solid phase - ANSWER: Molecules rigidly connected and vibrate.
Chemical changes - ANSWER: Bonds breaking, combustion, new substances form.
Produces new kinds of matter
Physical changes - ANSWER: Transitions between s/l/g, no breaking of bonds,
density, conductivity, solubility, color, hardness, melting and boiling points
Symbol
Atomic mass
Atomic number - ANSWER: Symbol: C
Atomic Mass: 12 (protons + neutrons)
Atomic Number: 6 (protons)
In neutral atoms, p+=e-
(carbon has 6 electrons when neutral)
Why is writing a 6 and C redundant? - ANSWER: Elements are defined by their
atomic numbers. # of protons cannot change without changing the elements identity.
All carbon isotopes will all have 6 protons. So an atom with ^ protons will always be
Carbon. They mean the same thing.
Rutheford's Experiment/Gold foil experiment - ANSWER: Prediction:
-most particles pass through
-small deflections
No real interaction should happen
Observation:
-Most particles passed through undeflected
-Some particles deflected at large angles
-Some particles reflected back to source
Rutheford's experiment conclusion? - ANSWER: Most of an atom is empty space,
with a large, dense, positive mass in the center
, What is an element? - ANSWER: Pure chemical substance consisting of one type of
atom.
Which element is most abundant in the earth's crust? - ANSWER: Oxygen.
What is an atom? - ANSWER: Smallest particle of an element that retains the
characteristic properties of that element.
What is a compound? - ANSWER: Pure chemical substance consisting of two or
more different chemical elements.
What is the unique characteristic of chemical compounds? - ANSWER: They have a
unique and defined chemical structure. (H2O, always two hydrogen with one oxygen)
How are atoms arranged in compounds? - ANSWER: They consist of a fixed ratio of
atoms that are held together in a defined spatial arrangement by chemical bonds.
What type of bonds hold together molecular compounds? - ANSWER: Covalent
bonds.
What type of bonds hold together salts? - ANSWER: Ionic bonds.
What is a molecule? - ANSWER: Electrically neutral group of at least two atoms in a
definite arrangement that retains the composition and chemical characteristics of a
compound.
What are metals? - ANSWER: Elements that are shiny, malleable, and good
conductors of heat and electricity.
What are nonmetals? - ANSWER: Elements that appear dull and are poor conductors
of heat and electricity.
What are metalloids? - ANSWER: Elements that conduct heat and electricity
moderately well, and possess some properties of metals and some properties of
nonmetals.
Main group metals, transition metals, metalloids, non-metals - ANSWER:
Alkali metals, alkaline earth metals, halogens, noble gases - ANSWER:
What is an ionic bond? - ANSWER: One atom loses an electron, becomes positive
cation. One atom gains a valence electron and becomes a negative anion. Due to this,
the two atoms are attracted to each other.
What is a covalent bond? - ANSWER: Two atoms share a pair of valence electrons.
What is a polar covalent bond? - ANSWER: Sharing of the valence electron pair is
unbalanced, causing one atom to be more negatively charged than the other.