properties of water
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Properties of WaterPractice Quiz
1. What two elements make up water?
Hydrogen (H) & Oxygen (O)
H2O2. 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
methaneHydrogen 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?
AB
No
13. With a hydrogen bond between them, will molecule A be able to drag molecule B along with it?
AB
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
(+)(+)(+)(+)(+)
(-)
glassWater 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?
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.00
0.54
0.42
0.21 0.20 0.190.12 0.09
0.03 0.02
Heat Capacity of Various Materials [cal/(g·°C)]
Heat
Cap
acit
y [c
al/(
g·°C
)] Heat Capacity
21. Which substance in the chart is able to absorb the most heat for a given change in temperature?
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.00
0.54
0.42
0.21 0.20 0.190.12 0.09
0.03 0.02
Heat Capacity of Various Materials [cal/(g·°C)]
Heat
Cap
acit
y [c
al/(
g·°C
)] Water
22. Which substance in the chart is able to absorb the least amount of heat for a given change in temperature?
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.00
0.54
0.42
0.21 0.20 0.190.12 0.09
0.03 0.02
Heat Capacity of Various Materials [cal/(g·°C)]
Heat
Cap
acit
y [c
al/(
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?
watersugarcorn syrupCO2
caramelcaffeinecitric acid
BeefOnionTomatoLettuceCheeseKetchupMustardbread
copperzinc
26. What are two kinds of mixtures made with water?
Solutions and suspensions
27. Compare solvent, solute, and solution.
Sugar water
solutionwater
solventwhat does the
dissolving
Sugar cubes
solutewhat 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 polarNon polar
paraffin waxMagnesium sulfatepolar
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 cleanerLemon juice
Human bloodSoap
Oven cleaner
Lemon juice
Pure waterHuman blood
Soap
40. Place the 5 substances listed below on the scale to the right.
Pure waterClick 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