Sunday, December 9, 2018
Exam review 2018: Saturation
Note:
Supersaturated solutions are usually prepared by addition of heat to dissolve more solute. Supersaturated solutions are unstable, solute will re-crystallize when the solution is disturbed.
Exam Review 2018: Solutions (Multiple Choice)
1. Which of the following
statements concerning a saturated
solution is incorrect?
a)
Undissolved solute must be present.
b)
Undissolved solute may or may not be present.
c)
Undissolved solute, if present, is continually dissolving.
d)
Undissolved solute, if present, is in equilibrium with dissolved
solute.
2. Which of the following
statements concerning a saturated
solution is incorrect?
a)
Undissolved solute must be present.
b)
Undissolved solute may or may not be present.
c)
Undissolved solute, if present, is continually dissolving.
d)
Undissolved solute, if present, is in equilibrium with dissolved
solute.
3. Which of the following
statements concerning factors that affect solute solubility is incorrect?
a)
Most solid solutes become more soluble in water with increasing
temperature.
b)
Most solid solutes become less soluble in water with decreasing
pressure.
c)
Gaseous solutes become less soluble in water with increasing
temperature.
d)
Gaseous solutes become more soluble in water with increasing pressure.
4. Calculate the concentration
in % (m/m) of a solution containing 20.0 g of NaCl dissolved in 250.0 g of H2O.
a)
6.76% (m/m)
b)
7.41% (m/m)
c)
8.00% (m/m)
d)
8.25% (m/m)
5. The defining expression for
the molarity concentration unit is
a)
moles of solute/liters of solution.
b)
moles of solute/liters of solvent.
c)
grams of solute/liters of solution.
d)
grams of solute/liters of solvent.
6. A solution is made by
dissolving 0.40 mole of NaCl in enough water to give a final volume of 250.0
mL. What is the molarity of the solution?
a)
0.10 M
b)
0.80 M
c)
1.6 M
d)
2.5 M
7. Compared to pure water, a 1
M sugar-water solution will have a
a)
lower vapor pressure, lower boiling point and lower freezing point.
b)
higher vapor pressure, higher boiling point and higher freezing point.
c)
lower vapor pressure, higher boiling point and lower freezing point.
d)
lower vapor pressure, lower boiling point and higher freezing point.
8. Which of the following
statements about solutions is correct?
a)
A solution is a homogeneous mixture.
b)
It is possible to have solutions in which both solute and solvent are
solids.
c)
Solutions readily separate into solute and solvent if left undisturbed
for 24 hours.
d)
more than one correct response
e)
no correct response
9. A crystal of solid NaCl is
placed into an aqueous NaCl solution. It
is observed that most, but not all, of the crystal dissolves. This means the
original solution was
a)
supersaturated.
b)
unsaturated.
c)
dilute.
d)
more than one correct response
e)
no correct response
10. In which of the following
pairs of properties are both members of the pair colligative properties?
a)
density, boiling point
b)
vapor pressure, osmotic pressure
c)
solubility, freezing point
d)
more than one correct response
e)
no correct response
11. Consider the following
substances and their polarities: A –
polar, B – polar, C – nonpolar, D – nonpolar.
It is true that
a)
A is more soluble in C than in B.
b)
C is more soluble in D than in A.
c)
D is more soluble in B than in C.
d)
more than one correct response
e)
no correct response
12. Which of the following
solutions has a molarity of 1.0?
a)
0.050 mole of solute in 25.0 mL of solution
b)
2.0 moles of solute in 500.0 mL of solution
c)
3.0 moles of solute in 1.5 L of solution
d)
more than one correct response
e)
no correct response
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