CHEMISTRY IN CONTEXT
QUIZ #10: SOLUTIONS, PAGE 1
DECEMBER 12, 2006
**NAME
Solutions
** Placing your name in this blank indicates
that you will abide by The Lexington School Honor Code.
DIRECTIONS:
PART A -- MULTIPLE CHOICE
FILL IN THE BLANK with the response that BEST ANSWERS each
question or BEST COMPLETES each sentence. Each blank will have
only one correct response.
For questions #1-4, refer to the following passage:
The ocean is vast liquid world teaming with life. From the species that are highest on the food
chain like sharks, tuna, and marlin to the tiniest creatures like plankton and microscopic shrimp,
every organism depends upon the concentration of salts that determine the water’s salinity. The
salts cannot be seen but are distributed evenly and hidden in the ocean water.
In tidal pools on shorelines, pools of water have different salinities due to evaporation of water
leaving the salts behind. As well, in many coastal wetlands and estuaries, considered Mother
Nature’s nursery, freshwater from rivers meets salt water from the ocean and changes salt
concentrations.
1)
Which of the following is a solute in a heterogeneous mixture?
A)
salt
B)
Mother Nature
C)
tuna
2)
A coastal wetland often has
influx of freshwater from rivers.
A)
lower
B)
higher
concentrations of salt than the ocean due to
3)
As the water evaporates from tidal pools, salt concentration is likely to
A)
increase
B)
decrease
4)
Which of the following is a solute in a homogeneous mixture?
A)
salt
B)
microscopic shrimp
C)
marlin
.
CHEMISTRY IN CONTEXT
QUIZ #10: SOLUTIONS, PAGE 2
DECEMBER 12, 2006
**NAME
5)
An example of an alloy is
A)
ocean water
B)
iodine
C)
brass
6)
The solvent in an aqueous solution is
A)
always acetone.
B)
never water.
C)
always water.
7)
In our solubilities lab, which of the following was NOT a solute?
A)
acetone
B)
glycerine
C)
sulfur
DIRECTIONS:
.
.
PART B – SHORT ANSWER
Answer the following questions in a FEW COMPLETE SENTENCES.
Use lecture concepts and vocabulary as appropriate.
8)
What is a catalyst? Identify and describe two catalysts in solution-making.
9)
How are compounds and mixtures alike? How are they different?
CHEMISTRY IN CONTEXT
QUIZ #10: SOLUTIONS, PAGE 3
DECEMBER 12, 2006
DIRECTIONS:
**NAME
PART C – WORD PROBLEMS
Use PROBLEM-SOLVING TECHNIQUE to answer the following
questions.
10)
What mass of sodium chloride is necessary to dissolve in 100mL of water to create a
20g/mL concentration solution?
11)
What volume of water is necessary to create a 2.5g/mL solution if I have 40grams of salt?
12)
I am running out of my barium iodide solution! I made it using 1200mL of water and
250 grams of barium iodide. I need to make some more at the same concentration but I only
have 50 grams of barium iodide remaining. What volume of water do I need?
CHEMISTRY IN CONTEXT
QUIZ #10: SOLUTIONS, PAGE 4
DECEMBER 12, 2006
DIRECTIONS:
STATION A
13)
14)
15)
*16)
STATION B
17)
18)
**NAME
PART D – LAB PRACTICAL
Answer the questions at the lab stations using the materials provided.
Observe STANDARD PRECAUTIONS.