The Medical College - Page 43
Passage IX (Questions 121–125)
Colligative properties of solutions are those
proper-
ties that depend on the concentration of
molecules or
ions in solution rather than on their
identities.
121.
The freezing point of 1000g of water would
be
lowered most by the addition of one mole
of:
A.
ethylene glycol.
C.
Na2SO4.
B.
sodium chloride.
D.
ethyl alcohol.
122.
Calculations of freezing point depression
result-
ing from solutes are based on:
A.
molarity.
C.
mole fraction.
B.
molality.
D.
A and B.
123.
Colligative properties include:
A.
boiling point elevation.
B.
freezing point depression.
C.
osmotic pressure.
D.
more than one of the above.
124.
It is noted that the addition of 46g of a solute
to
1000g of water will lower the freezing point
of
water to –2°C. It could be predicted
that the
addition of 92g of the same solute to an
identical
1000g of water in another container
will:
A.
lower the freezing point to
–4°C.
B.
lower the freezing point to
–8°C.
C.
produce a freezing point of
0°C.
D.
produce a freezing point of
+2°C.
125.
Several beakers are prepared, containing
1000g
of the same solvent in each. Five grams of
non-
ionizing solutes are added, one solute to
each
beaker. The greatest effect on boiling point
will
be noticed with the solute with
the:
A.
highest molecular weight.
B.
highest melting point.
C.
lowest molecular weight.
D.
lowest melting point.
Passage X (Questions 126–135)
In a neutral atom, the number of orbital
electrons is
equal to the number of protons in the nucleus
(atomic
number). Orbital electron configurations may be
shown
in shorthand form and may be used to predict
reactivity
and valence. Krypton, for example, may be shown
as
1s
22s22p63s23p63d104s24p6. Neon is 1s22s22p6.
126.
A neutral atom of the element 1s
2 2s22p63s1
would be expected to:
A.
readily lose an electron to become an
ion
with a charge of +1.
B.
readily lose two electrons to become an
ion
with a charge of +2.
C.
readily gain three electrons to become
an
ion with a charge of –3.
D.
be an unreactive (noble) element.
127.
The above element has an atomic number
of:
A.
8.
C.
18.
B.
11.
D.
19.
128.
A
neutral
atom
of
the
element
1s
22s22p63s23p63d104s24p5
would be expected to
react by:
A.
losing one electron.
B.
losing two electrons.
C.
gaining one electron.
D.
gaining three electrons.
129.
An atom of atomic number 9, having an
electron
configuration of 1s
22s22p6, would be:
A.
a neutral atom.
B.
an ion with a charge of +1.
C.
a noble element.
D.
an ion with a charge of –1.
130.
An atom of atomic number 11, having an
elec-
tronic configuration of 1s
22s22p63p1, would be:
A.
a neutral atom at ground state.
B.
an ion with a charge of +1.
C.
a neutral atom at an excited
state.
D.
an ion with a charge of –1.
131.
Noble elements include all of the
following
EXCEPT:
A.
helium.
C.
neon.
B.
argon.
D.
scandium.
132.
The number of quantum numbers possessed
by
each orbital electron is:
A.
one.
C.
three.
B.
two.
D.
four.
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