Properties of water
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Properties of Water. Practice Quiz. Hydrogen (H) & Oxygen (O). 1. What two elements make up water?. 2. Write the chemical formula for water. H 2 O. 3. Is water an element, compound, or mixture?. Compound.

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Properties of Water

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Properties of Water

Practice Quiz


Hydrogen (H) & Oxygen (O)

1. What two elements make up water?

2. Write the chemical formula for water.

H2O

3. Is water an element, compound,

or mixture?

Compound


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

4. Define the term compound.

5. What kind of chemical bond exists

between a hydrogen and oxygen

atom in a water molecule?

A covalent bond


6. Draw a model of a water molecule.

(+)

(+)

The parentheses mean ‘partial.’

(-)

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

the water molecule you drew above.

(-)

δ +

This symbol also means partial →


8. Which of the following molecules are polar?

(-)

(-)

(-)

(+)

(+)

(+)

(-)

(-)

(+)

carbon dioxide

water

ammonia

(+)

(+)

(+)

(+)

(-)

(-)

(-)

(+)

(-)

(-)

(-)

(+)

(+)

(+)

(+)

Hydrogen chloride

formaldehyde

methane


1

(-)

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

Hydrogen bond

9. Draw two water molecules and a hydrogen bond.

2

(+)

3

4

10. How many hydrogen bonds can a water

molecule form with other water molecules?

Four


Cohesion

B

A

11. What term describes the attraction between molecules of the same substance?

No

12. Without a hydrogen bond, when molecule A

moves to the right, will it be able to drag

molecule B along with it?


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

A proboscis keeps this bee at a safe distance

Insect trapped in water


15. What are some examples where

surface tension breaks down?

“Scaring” pepper

Bread clip motor boat


Adhesion

(+)

16. What term describes the attraction between molecules of different substances?

(+)

(+)

(-)

(+)

(+)

glass

Water drop on glass slide


The water will be attracted toward the rod

17. What will happen when a charged rod or balloon is brought up close to a stream of water?


18. What are some examples of water adhesion?

A meniscus that water forms in a glass tube.

Capillary action


19. What are some examples of anti-adhesion?

Scotchgard ® carpet

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?

Heat Capacity


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

most heat for a given change in temperature?

Water


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

least amount of heat for a given change in temperature?

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?

Beef

Onion

Tomato

Lettuce

Cheese

Ketchup

Mustard

bread

copper

zinc

water

sugar

corn syrup

CO2

caramel

caffeine

citric acid


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

Solutions and suspensions

27. Compare solvent, solute, and solution.

water

Sugar cubes

Sugar water

solvent

solution

solute

what does the dissolving

what 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?

Magnesium sulfate

oil

iodine

paraffin wax

salt

Non polar

polar

Non polar

Non polar

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?

Paint

Blood

Chocolate milk


When water breaks apart, what kind of ions

are formed?

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

()

+

(-)

33. What does the pH scale indicate?

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


34. What is the range of the pH scale?

0 to 14

What is the pH of a substance that has an

equal number of H+ and OH- ions?

7

Substances with a pH below 7 are ________

while those above 7 are _________?

Acids

Bases


37. Acids have more ____ions than _____ ions?

H+

OH-

38. The _______the pH, the greater the acidity.

lower

39. _______ have more OH- ions than H+ions?

Bases


Place the 5 substances

listed below on the

scale to the right.

Oven cleaner

Soap

Lemon juice

Oven cleaner

Human blood

Pure water

Human blood

Soap

Pure water

Click for answer

Lemon juice


The pH in most cells in the human body must

stay between _______ and______ ?

6.5

7.5

__________ are weak acids or bases that can

react with strong acids or bases to stop sharp,

sudden changes in pH.

Buffers

43. Buffers play an important role in the process of

______________, where living things are able

to maintain a stable, internal environment.

homeostasis


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