WATERThis slide show covers everything that you have to know about water.

You will be provided with “Water Notes”,. Please put away your own paper.

Put away your cell phones, other work, etc. Let’s start today with just pens/pencils, reference tables, and the water packet provided.

We will watch and mostly we will be thinking and talking. You will not need to write much at all.

Everyone in this room will talk today, more than once. If you know the answer that’s great. If you don’t know the answer that’s great too. Learning is our goal and you can’t possibly KNOW all of this already. Listen, think, be chemists, and most of all pay attention.

Objective: what are the 7 important properties of water, and what is the fundamental reason that they exist? Additionally some water vocabulary words + some review

What do we know about water? Formula? Shape? Atoms? Types of bonds between atoms inside the molecule? Type of bond between molecules? Compared to other small molecules, high or low BP? Density? Etc.

O H

H

1 + 2. Draw 7 molecules of water (randomly, not soldiers!) and with DOTTED LINES indicate the hydrogen bonding BETWEEN MOLECULES.

O H

H

O H

H

3. Hydrogen bonding: intermolecular attraction between polar molecules containing polar bonds containing hydrogen atoms. They help create super duper dipoles, or intermolecular magnetic attraction between molecules.

A water molecule with two DIPOLE ARROWS which show that H atoms are left more positive and O is more negative, due to the extreme difference in electronegativity value, the unfair sharing of valence electrons in these 2 single polar covalent bonds.

Get 6 magnet water

molecules now.

4 + 5.Which colors

are which atoms????

Say 6.HEXAGONSee the hole?Don’t forget the number 6 or that hole. Play.

7. If you squish the 6 magnets (water molecules) in your hands and move them slowly they take up less space than when in the ring shape. The density of pure water is ___________________________

or you could say it this way as well:

______________________________.

8. The density of ICE must be: _______________ since ice floats in liquid water.

9. The hole in the ring creates a slightly greater

__________________________ for the six molecules of water that the liquid water just doesn’t have.

10. What temperature does liquid water freeze at? ________________ K or ______________°C 11. To melt one gram of ice into one gram of water takes the

__________ of _____________________, 12. And for water, that constant is written this way: __________________________________

14. Put an ice cube in your hand - does the cold go into your hand or does your hand’s heat go into the ice?

15. Why does your hand get cold?

16. The energy it takes to MELT ICE is called the ________________ of ___________

17. For water that constant is on table B, and it’s written as ______________________

18. How many water molecules does it take to form a normal crystal of ice? _________

19. How many points, or sides, do ALL SNOW FLAKES have? _______________

snowflakes

The 7 Most Important Properties Of Water (and what causes them)

20. Water has a _____________ ______. This is due to ____________________.

The intermolecular hydrogen bonds hold the water molecules loose enough for them to move, but tight enough so that it’s hard to separate them apart into a gas. It takes lots of energy.

21. Water has a _____________ ______. This is due to ____________________.

The intermolecular hydrogen bonds hold the water molecules together which makes it harder for water to evaporate than molecules that have less intermolecular attraction.

22.Water has ________________.

This is due to ______________________________.

The intermolecular hydrogen bonds hold the water molecules tight to themselves and not at all to the air. This creates a “skin” or what is called surface tension. I hate those bugs, don’t you?

23. Solid water (ice) can ____________ on liquid water. This is due to ___________________.

Water molecules form rings of six, which creates a small “hole” in the center of them. It makes frozen water slightly less dense than liquid water. Liquid water molecules fit together more tightly, so liquid water is more dense.  

 

Many love stories are disasters.(think Romeo + Juliet)

This one made lots of money.Yours can be great even without the crashing into a hunk of ice.

24. Water has a very high ________________. This is due to ___________________.

25. The “C” for H2O is written this way: _________________________________

Without a pool heater (and some combustion of hydrocarbons releasing lots of heat joules) this is what it looks like at a pool in June and most of the summer.

Why? Because…

26. Water has ________________________________________________________.

This is due to ____________________________________.

 

27. This can be stated more casually as

_____________________________________

28. Water has the ability to form ______________________________________.

This is due to ______________________.

29. Two examples of these are: ___________________ + ____________________.

What are those dots???

ELEVEN WATER VOCABULARY Words to Memorize by Tomorrow. 1 Solvation: the process of dissolving into a liquid

2 Solute: dissolves into the solvent in a solution (the salt in salty water)

3 Solvent: the part of the solution that solute dissolves into (the water part)

4 Immiscible: when 2 liquids do not mix, like oil and water, due to a difference in polarity (water is a polar molecule, oil is a nonpolar molecule).

5 Miscible: when 2 liquids do mix because both are polar, or both are nonpolar LIKE DISSOLVES LIKE (example: water and alcohol)

6 Aqueous: dissolved in water

7 Soluble: able to dissolve

8 Insoluble: unable to dissolve, (precipitates)

9 Saturated: holding as much solute in solution as possible (Charlie choc. milk)

10 Unsaturated: holding less solute in solution than is possible (Janet choc. milk)

11 Supersaturated: holding more solute than is normally possible (not common)

Water Class #2

Objective: Mastering Table G – the Solubility Curves for 10 Compounds

Take it out now please

How concentrated a solution is makes a difference in chemistry. That solution could be chocolate milk, or salty water. Or sugar in coffee, or even ammonia in water for when you clean your toilets. All solutions contain solutes in solvents.

For salty water, which is the solute - which is the solvent?

For chocolate milk, which is the solute - which is the solvent?

For the ammonia solution? which is the solute - which is the solvent?

Each solvent can “HOLD” only a certain amount of solute at any temperature. That’s called the solubility of the solution, how much stuff fits into solution.

When you come to my house for chocolate milk and cookies, the cookies will be first rate (oatmeal, lemon, and chocolate chip).

Depends on if my wife Janet makes you chocolate milk, or I do, how well that will taste.

MINE

Janet’s

Table GSolubility Curves at Standard PressureThe table is funky do,

the most complex of all the tables we will use. It could more easily been 10 different graphs, which would take up more room, but easier to deal with.

Relax, we’ll only look at one line at a time, and we won’t get scared.

Table GSolubility Curves at Standard Pressure

30. Table G is titled: ______________________- at standard pressure - which is:__________ 31. The Y axis (up/down) is solubility

________________________________ which really means this: 32. ________________________________

__________________________________. Cross it out and replace it now. 33. The X axis across the bottom has the units

______________________.

Why doesn’t it go lower than zero or higher than 100?

Table GSolubility Curves at Standard Pressure

34. How many grams of KCl fits into 100 mL of water at 10°C? ____ 35. How many grams of SO2 fits into 100 mL of water at 40°C? ____ 36. How many grams of ammonium chloride fits into 100 mL of water at 5°C? ____ 

Table GSolubility Curves at Standard Pressure

37. How many lines are on this graph? ________ How many compounds are on this graph? __________ 38. How many lines go “up” as the temperature rises? ____________ 39. How many lines go “down” as the temperature rises? ________ 40. How many of these compounds are IONIC? ________ 41. How many of these compounds are COVALENT or MOLECULAR? ___________

42. State something sensible about the last 4 statements that proves you are awake: 

Table GSolubility Curves at Standard Pressure

43. How many lines can you look at on this graph at any time? ____

44. When something like KI or NaCl goes into water, what particles end up in the water? ______________

45. When something like sugar C12H22O11, or CO2 go into water, what particles end up in the liquid water? ______________________

46. How many g of NH3 fit into 100 mL of water at 90°C?

____

47. When water (or any solvent) holds the maximum amount of solute at a given temperature, this solution is said to be:

____________________________THINK: How would you figure out this problem? Don’t do it yet! (ok, do it if you must, show your work) 

48. How many grams of ammonia fit into 50 mL of water at 90°C _______ (COPY THIS ALL)

48. How many grams of ammonia fit into 50 mL of water at 90°C

90°C NH3

water10 g

100 mLx g

50 mL

100 x = 500

x = 50 g NH3

49. How many grams of KCl fit into 100 mL of water at 10°C? _________

50. How many grams of KCl fit into 350 mL of water at 10°C? _____ (show work!)

49. How many grams of KCl fit into 100 mL of water at 10°C? 30g

50. How many grams of KCl fit into 350 mL of water at 10°C? 105g

10°C KClwater

30 g100 mL

x g350 mL

100 x = 10500

x = 105 g KCl (3 SF)

51. How many grams of NH3 fit into 100 mL of water at 10°C?

________

52. How many grams of NH3 fit into 12.0 mL of water at 10°C? ____

(show work!)

51. How many grams of NH3 fit into 100 mL of water at 10°C?

________

52. How many grams of NH3 fit into 12.0 mL of water at 10°C? ____

(show work!)

10°C NH3

water70 g

100 mLx g

12.0mL

100 x = 840

x = 8.4 g NH3 (3 SF)

This question is the same type, but asked a bit differently:

53. How many grams of KClO3 solute fits into 844 mL of water at 373 Kelvin? (show work) 

53. How many grams of KClO3 solute fits into 844 mL of water at 373 Kelvin?

100°C KClO3

water60 g

100 mLx g

844 mL

100 x = 50640

x = 506 g KClO3 (3 SF)

This question is the same type, but again, asked a bit differently:

54. How many grams of sodium nitrate will it take to saturate 64.0 mL of water at 283 Kelvin? 

54. How many grams of sodium nitrate will it take to saturate 64.0 mL of water at 283 Kelvin?

10°C NaNO3

water80 g100 mL

x g64.0 mL

100 x = 5120

x = 51.2 g NaNO3 (3 SF)

55. Why does NY State Regents put 10 curves on one graph called table G? 56. Should this ever get to you?  57. 100 mL of water has the mass of ___________________________ 58. The density of pure water is _____________________________ 59. Do other elements or substances have this 1 gram = 1 mL or 1 gram = 1 cm3? ______________

Why not?

60. What’s so special about this table G graph?

Water Class #3

Objective: More table G practice, more Water Vocabulary, and oil in water!

Shade in the 2 liquids in the tube. Label them OIL & Water 61. ___________________ 62. ___________________

63. They do not mix because

___________________________________________ 64. In this case the OIL is ______________________

and the water is _______________________. 65. The reason that the oil is ON TOP and not on under the water is:

________________________________________________________________________

____________________________________________________________________.

66. When a solution holds the most solute possible in the solvent it is said to be ________________________

67. If the solution holds LESS than that maximum amount of solute, it’s called:

________________________

68. Charlie Chocolate milk would be ____________________

while Janet’s is ____________________

69. Is a 100 mL HCl(AQ) at 80°C saturated if it

contains 37 g

of HCl? __________

70. Is a 100 mL NaNO3(AQ) at 25°C saturated if it contains 90.0 g NaNO3? ________

71. How many grams of NaCl will saturate 100 mL of 90°C water? ________ grams

 

72. If you attempted to put 43 grams NaCl into that 100 mL of 90°C water, what would happen?  

73. Will a 100 mL NaCl(AQ) at 90°C be saturated if it

contains 43 g NaCl?

__________  

In these solutions, are they saturated or unsaturated? If unsaturated, how many more grams of solute can fit?

Temp Solute

If a solution contains this Mass

in g

Is it Saturated or Unsaturated?

If unsaturated, how many more grams are

neededto saturate this

solution?

74 30°C HCl 60 g

75 60°C KNO3 100 g

76 10°C NaNO3 80 g

77 90°C NH4Cl 73 g

78 20°C KCl 20 g

79 5°C NaCl 31 g

In these solutions, are they saturated or unsaturated? If unsaturated, how many more grams of solute can fit?

Temp Solute

If a solution contains this Mass

in g

Is it Saturated or Unsaturated?

If unsaturated, how many more grams are

neededto saturate this

solution?

74 30°C HCl 60 g UN ~7 grams more

75 60°C KNO3 100 g UN ~5 grams more

76 10°C NaNO3 80 g SAT zero

77 90°C NH4Cl 73 g SAT zero

78 20°C KCl 20 g UN ~13 grams more

79 5°C NaCl 31 g UN ~6 grams more

80. Below are 2 NaCl formula units that have ionized into water. Draw 3 water molecules surrounding each ion showing proper orientation towards these ions. Note their charges indicated in the little circles.    

 81. Explain in one sentence why the water molecules are going to orient themselves to these ions in solution.

 Na +1

 Na+1Cl-1

Cl -1

82. Oil molecules (vegetable oil, motor oil, mineral oil, etc.) are all nonpolar. When oil is put into (polar) water, why can’t the oil dissolve into the water like salts, or polar sugar molecules?

83. How many grams of NaCl fits into 100 mL of water at 90°C _______________

84. How many grams of NaCl fits into 100 mL of water at just 10°C _____________

THINK HARD NOW… 85. If you have a saturated KClO3(AQ) at 90°C and put it into a cooler and the temperature drops to just 40°C, what could possibly happen to all that KClO3 that was in solution?

THINK HARD NOW… 85. If you have a saturated KClO3(AQ) at 90°C and put it into a cooler and the temperature drops to just 40°C, what could possibly happen to all that KClO3 that was in solution?

 About 52 grams of KClO3would be in solution when 90°C , but only about 16 grams fits in when it’s cooled to 40°C . Since this potassium chlorate is matter, it can’t be created or destroyed, it has to go somewhere. It drops OUT of solution, to the bottom of the beaker.

86. Your saturated solution of KNO3 is at 60°C and 100 mL. You cool it down to 20°C. Describe what happens. Do the MATH too!

86. Your saturated solution of KNO3 is at 60°C and 100 mL. You cool it down to 20°C. Describe what happens. Do the MATH too!

105 grams of potassium nitrate is in solution when warmer, but only 35 grams of potassium nitrate fits when colder.

The difference is the amount that FALLS OUT OF SOLUTION to the bottom of the beaker.

105 g – 35 g = 70 grams of precipitate

Your saturated solution of KNO3 is at 60°C and 100 mL. You cool it down to 20°C. Describe what happens. Do the MATH too!

At 60°C the solution holds 105 grams of this solute.

At 20°C the solution holds 35 grams of this solute.

The difference (105 – 35 = 70 grams) falls out of solution because this colder solution can’t hold all of that solute.

Use the Table G graph to figure this out.

87. What happens when you put 140 g KI into 100 mL water at 10°C?

__________________________________________________________________ __________________________________________________________________.

 88. Does this “STOP”?

89. What does happen? _______________________

 Draw a picture of this and label it all properly too. 

90. _____________________

91. _____________________

92. In a _____________ ________________,

the rate of the ____________________ reaction is equal to the rate of the

_________________________ reaction.  93. In this case we could say that the rate of rate of

_________________ ________________. 

=

When NaCl(S) → Na+1(AQ) + Cl-1

(AQ) this is

called _________________

or _______________

Does sugar, C12H22O11 do this? ______

How does sugar dissolve into water?

  SubstanceIs this an

electrolyte?Will this conduct

electricity?

94 NaCl(AQ)    

95 NaCl(S)    

96 NaOH(AQ)    

97 NaOH(S)    

98 AgCl(S)    

99 AgCl(AQ)    

100 C12H22O11(AQ)    

  SubstanceIs this an

electrolyte?Will this conduct

electricity?

94 NaCl(AQ) Yes  Yes

95 NaCl(S) Yes No

96 NaOH(AQ) Yes Yes

97 NaOH(S) Yes No

98 AgCl(S) No No

99 AgCl(AQ) Does not exist Check table F! (no)

100 C12H22O11(AQ) No No (no ions in solution)

101. Is Be(OH)2 an electrolyte? ______________

Can it conduct electricity? _____________________

102. What about Be(OH)2(L) (melted beryllium hydroxide)

Will that be able to conduct electricity? _______

103. How is that possible? ________________________________

104. If liquid Be(OH)2 can conduct electricity, it that an electrolyte? __________________________

105.  When sodium chloride goes into water, we would write the “equation” this way:

_____________________________________

106.  This is called ____________________ or

_________________________

107. Does sugar do this? ___________

What does sugar do?

__________________________________

105.  When sodium chloride goes into water, we would write the “equation” this way: NaCl(S) Na+1

(AQ) + Cl-1(AQ)

106.  This is called DISSOCIATION or

IONIZATION

107. Does sugar do this? NO

What does sugar do? Sugar is NOT IONIC, it dissolves because the molecules are POLAR, but it dissolves into molecules.

108. Show the dissociation or the ionization for sodium acetate in water with phase symbols:

108. Show the dissociation or the ionization for sodium acetate in water with phase symbols:

NaC2H3O2(S) Na+1(AQ) + C2H3O2

-1(AQ)