Properties of Water

frizzflowerUrban and Civil

Nov 29, 2013 (4 years and 1 month ago)

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Properties of Water

Practice Quiz

1. What two elements make up water?

Hydrogen (H) & Oxygen (O)

H
2
O

2. Write the chemical formula for water.

3. Is water an element, compound,



or mixture?

Compound

4. Define the term compound.

A substance with two or more elements
chemically combined in definite proportions.

A covalent bond

5. What kind of chemical bond exists



between a hydrogen and oxygen



atom in a water molecule?

6. Draw a model of a water molecule.

7. Draw partial (+) and partial (
-
) charges on


the water molecule you drew above.

δ

+

This symbol also means partial →

(
+
)

(
+
)

(
-
)

(
-
)

The parentheses mean ‘partial.’

8. Which of the following molecules are polar?

(
+
)

(
+
)

(
-
)

(
-
)

(+)

(
-
)

(
-
)

(
-
)

(
-
)

(
-
)

(
+
)

(
+
)

(
+
)

(
+
)

water

carbon dioxide

methane

Hydrogen chloride

(
-
)

(
+
)

(
+
)

(
+
)

(
-
)

(
-
)

formaldehyde

(
-
)

(
+
)

(
+
)

(
+
)

ammonia

9. Draw two water molecules and a hydrogen



bond.

10. How many hydrogen bonds can a water


molecule form with other water molecules?

2

(+)

(
-
)

Hydrogen bond

The use of dashed lines
show that hydrogen bonds
are relatively weak.

Four

3

1

4

11. What term describes the attraction between



molecules of the same substance
?

Cohesion

12. Without a hydrogen bond, when molecule A



moves to the right, will it be able to drag



molecule B along with it?

A

B

No

13. With a hydrogen bond between them, will



molecule A be able to drag molecule B along



with it?

A

B

Yes

14. What are some examples of water cohesion?

Surface tension

Drops on a penny

Insect trapped
in water

A proboscis keeps
this bee at a safe
distance

15. What are some examples where



surface tension breaks down?

“Scaring” pepper

Bread clip motor boat

16. What term describes the attraction between



molecules of different substances
?

Adhesion

(+)

(+)

(+)

(+)

(+)

(
-
)


glass

Water drop on glass slide

17. What will happen when a charged rod or balloon



is brought up close to a stream of water
?

The water will be attracted toward the rod

18. What are some examples of water adhesion?

A

meniscus that
water forms in a
glass tube.

Capillary action

Scotchgard

® carpet

19. What are some examples of anti
-
adhesion?

Wax
-
layer on leaves

Water on wax paper

Duck feathers
repel water

New: Researchers have made an
omniphobic

material that repels both water and oil.

Nature has never made this type of material.

20. What is the term which describes the amount of heat



energy needed to increase a substance’s temperature?

1.00

0.54

0.42

0.21

0.20

0.19

0.12

0.09

0.03

0.02

0.00
0.20
0.40
0.60
0.80
1.00
1.20
Heat Capacity [cal/(g∙
°
C)]

Heat Capacity of Various Materials
[cal/(g∙
°
C)]

Heat Capacity

21. Which substance in the chart is able to absorb the



most heat for a given change in temperature?

1.00

0.54

0.42

0.21

0.20

0.19

0.12

0.09

0.03

0.02

0.00
0.20
0.40
0.60
0.80
1.00
1.20
Heat Capacity [cal/(g∙
°
C)]

Heat Capacity of Various Materials
[cal/(g∙
°
C)]

Water

22. Which substance in the chart is able to absorb the



least amount of heat for a given change in temperature?

1.00

0.54

0.42

0.21

0.20

0.19

0.12

0.09

0.03

0.02

0.00
0.20
0.40
0.60
0.80
1.00
1.20
Heat Capacity [cal/(g∙
°
C)]

Heat Capacity of Various Materials
[cal/(g∙
°
C)]

Air

23. What example in the Properties of Water lab



demonstrated a low heat capacity for air and a



high heat capacity for water?

Air
-
filled balloon

Water
-
filled balloon

24. What is a mixture?

A substance made up of elements or compounds that are
combined but not chemically bonded together.

25. What are some examples of mixtures?

water

sugar

corn syrup

CO
2

caramel

caffeine

citric acid

Beef

Onion

Tomato

Lettuce

Cheese

Ketchup

Mustard

bread

copper

zinc

26. What are two kinds of mixtures made with water?

Solutions and suspensions

27. Compare solvent, solute, and solution.

Sugar water

solution

water

solvent

w
hat does the
dissolving

Sugar cubes

solute

w
hat is being
dissolved

28. Define a solution?

A mixture in which the molecules of the mixed
substances are evenly spread out.

29. Which substance(s) below dissolve in water?

salt

polar

oil

Non polar

Non polar

paraffin wax

Magnesium
sulfate

polar

iodine

Non polar

30. What is a suspension?

A mixture from which some of the
nondissolved

particles settle out slowly upon standing.

31. What some examples of suspensions?

Chocolate
milk

Paint

Blood

33. What does the pH scale indicate?

It indicates the concentration of
hydrogen ions (H
+
) in a solution.

32.

When water breaks apart, what kind of ions



are formed?

Hydrogen (H
+
) ions and hydroxide (OH
-
) ions


+

(
-
)

(


)

34. What is the range of the pH scale?

0 to 14

35.

What is the pH of a substance that has an



equal number of H
+

and OH
-

ions?

7

36.

Substances with a pH below 7 are ________



while those above 7 are _________?

Acids


Bases


37. Acids have more ____ions than _____ ions?

38. The _______the pH, the greater the acidity.

lower

H
+


OH
-


39. _______ have more
OH
-

ions than
H
+

ions?

Bases


Oven cleaner

Lemon juice

Human blood

Soap

Oven cleaner

Lemon juice

Pure water

Human blood

Soap

40.
Place the 5 substances



listed below on the



scale to the right.

Pure water

Click for answer

41.

The pH in most cells in the human body must



stay between _______ and______ ?

42.
__________ are weak acids or bases that can



react with strong acids or bases to stop sharp,



sudden changes in
pH.

Buffers

6.5

7.5


43. Buffers play an important role in the process of


______________, where living things are able



to maintain a stable, internal environment.

homeostasis