Waterworks Operations II

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Waterworks Operations II

• Lecture 2
• Water Properties/Chemistry
• A Review

http//www.mansfield.ohio-state.edu/sabedon/biol1
015.htmhydrogen_bond
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Key Words

• Solute- The substance that dissolves to form a
  solution
• Solvent- substance in which another substance is
  dissolved, forming a solution.
• Solution- a medium consisting of solutes and
  solvents
• Hydration- formation of water molecules around an
  ion.
• Ions- electrically charged atoms
• Cohesion- attraction of a water molecule to
  another water molecule via hydrogen bonding
• Adhesion- attraction of a water molecule to a non
  water molecule

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Substance in which another substance is
dissolved, forming a solution.

1. Solute
2. Solvent
3. Solution

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A medium consisting of solutes and solvents

1. Solute
2. Solvent
3. Solution

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The substance that dissolves to form a solution

1. Solute
2. Solvent
3. Solution

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Cohesion is _________.

1. The attraction of one water molecule to another
   resulting from hydrogen bonding
2. involves the attraction of a water molecule to a
   non-water molecule.
3. Influenced by water being a non polar molecule
4. All of the above

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Key Words
Sublimation is the phase change as a substance
changes from a solid to a gas without passing
through the intermediate state of a liquid.
Triple POINT - The temperature and pressure at
which the solid, liquid, and gas phases exist
simultaneously. 273.16 K (0.01 oC) and a
pressure of 611.73 pascals (ca. 6.1173 millibars,
0.0060373057 atm). Critical POINT - The
temperature above which a substance will always
be a gas regardless of the pressure. around 647
oK (374 oC or 705 oF) and 22.064 MPa (3200 PSIA
or 218 atm). Freezing Point - The temperature at
which the solid and liquid phases of a substance
are in equilibrium at atmospheric pressure.
Boiling Point - The temperature at which the
vapor pressure of a liquid is equal to the
pressure on the liquid. Normal (Standard)
Boiling Point - The temperature at which the
vapor pressure of a liquid is equal to standard
pressure (1.00 atm 760 mmHg 760 torr
101.325 kPa)
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The phase change as a substance changes from a
solid to a gas without passing through the
intermediate state of a liquid.

1. Sublimation
2. Freezing point
3. Critical point
4. Boiling point

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The temperature above which a substance will
always be a gas regardless of the pressure.

1. Triple Point
2. Critical Point
3. Freezing point
4. Boiling point

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Water

• Water covers 70-80 of earths surface
• 97 of earths water in the oceans!
• 3 freshwater
• 98 of the 3 of freshwater that is used as
  drinking water is groundwater!

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What percentage of the water used in the United
States comes from underground sources?

1. 45
2. 30
3. 60
4. 90

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Nearly 95 percent of the rural population of the
US relies on ground water.

1. True
2. False

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Water

• Life evolved in water, 70 human body
• Centigrade scale (0oC freeze) based on (100oC
  boil) water prop.
• Most common molecule that exists as a liquid at
  ambient temperatures
• Unique properties
• high polarity, hydrogen bonding, cohesion,
  adhesion. high specific heat, high heat of
  vaporization, polar solvent

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Which of the following is true about water?

1. Universal solvent
2. High heat capacity
3. High heat of vaporization
4. Liquid rather then a gas at room temperature
5. All of the above

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Water

• Structure
• Tetrahedral (arrangement of electrons)
• two hydrogen's (positive)
• One oxygen (negative)
• (O) two non-bonding electron pairs
• Polar molecule
• partial (H) at one end,
• partial (O) at the other end
• excellent solvent

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Water is a polar molecule ?

1. True
2. False

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Water (hydrogen bonding)

• hydrogen bond bonding between oxygen and
  hydrogen (not strong)
• -Weak individually, stronger in larger
  quantities.
• Hydrogen bonding is responsible for
• - liquid rather then gas at room temp
• - high specific heat, heat of vaporization
• - universal solvent
• - adhesion
• -cohesion- sticks together liquid instead of
  changing to gas

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Water (High Specific Heat)

• Specific Heat- The amount of heat needed to raise
  the temperature of one gram of a substance by
  1C.
• -a temperature increase is an increase in the
  motion of the molecules and atoms making up a
  substance.
• water molecules resist increasing their motion.
  (this is another way of saying that is water
  molecules resist the net breaking of hydrogen
  bonds)
• water resists heating water has a very high
  specific heat.

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Water High Heat Vaporizationboiling

• Heat of Vaporization- The amount of heat required
  to convert a unit mass of a liquid at its boiling
  point into vapor
• Vaporization is the breaking of hydrogen bonds
  (water has a lot of hydrogen bonding)
• water resists vaporizing (evaporating).
  Consequently, it takes a lot of heat to evaporate
  water.

normal boiling point of 100 ºC, the latent
specific latent heat of vaporization is 2260
kJ.kg-1.
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Water High Latent Heat of Fusion melting

• Latent Heat of Fusion- the amount of heat
  required to convert a unit mass of the solid into
  the liquid without a change in temperature
• Need to add a lot of energy to break apart
  hydrogen bonds.

Water has a heat of fusion of 143 Btu/lb.
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Which of the is responsible for water being a
liquid rather then gas at room temp?

1. Hydrogen bonding
2. High heat capacity
3. High heat of vaporization

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The amount of heat required to convert a unit
mass of the solid into the liquid without a
change in temperature?

1. Hydrogen bonding
2. Specific Heat
3. Heat of vaporization
4. Latent Heat of Fusion

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The amount of heat required to convert a unit
mass of a liquid at its boiling point into vapor ?

1. Hydrogen bonding
2. Specific Heat
3. Heat of vaporization
4. Latent Heat of Fusion

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The amount of heat needed to raise the
temperature of one gram of a substance by 1C?

1. Hydrogen bonding
2. Specific Heat
3. Heat of vaporization
4. Latent Heat of Fusion

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Hydrochloric acid is a better solvent then water ?

1. True
2. False

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Heating/Cooling Curve
100oC
0oC
Freezing is the phase change as a substance
changes from a liquid to a solid. Melting is the
phase change as a substance changes from a solid
to a liquid. Condensation is the phase change as
a substance changes from a gas to a liquid.
Vaporization is the phase change as a substance
changes from a liquid to a gas.
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Gas
Liquid
Uptake of heat by 1 kg of water, as it passes
from ice at -50 ºC to steam at temperatures above
100 ºC
Solid
A Rise in temperature as ice absorbs heat.B
Absorption of latent heat of fusion.C Rise in
temperature as liquid water absorbs heat.D
Water boils and absorbs latent heat of
vaporization.E Steam absorbs heat and thus
increases its temperature.
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Water (Universal Solvent)

• Water tends to very effectively dissolve
  hydrophilic (water loving) substances

Phil Lesh
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Water
salts and solids solubility
ZClO4, ZNO3 all Z soluble
ZCl most Z soluble (PbCl2, Hg2Cl2, AgCl, AuCl)
ZSO4 most Z soluble (except CaSO4, BaSO4, PbSO4, Hg2SO4, Ag2SO4)
ZCO3, ZPO4, ZSiO4 most Z insoluble (except Na, K, NH4)
ZOH most Z insoluble (except Li, Na, K, NH4)
ZS most Z insoluble (except Na, K, NH4, Mg, Ca)

• Solvent
• high polarity
• good solvent for polar (salt) compounds

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Hydrophilic compounds have an affinity to water
and are usually charged or have polar side groups
to their structure that will attract water.
Hydrophobic are water hating compounds that are
repelled by water and are usually neutral (no
charge.)?

1. True
2. False

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Water
Why does ice float? Ice is less dense than
water, therefore it floats. Solid water
molecules form a ordered crystal through hydrogen
bonding that spaces the molecules farther apart
than when they were in a liquid (less dense).
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Water
liquid

• Density

ice
The density of solid water is actually less than
it could otherwise be because hydrogen bonded
water is packed slightly less favorably than
could be achieved without hydrogen bonding
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ammonia
vinegar
0
7
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Great Salt Lake
pure water
acid rain
sea water
acid mine drainage
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Activity
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Iron Mountain, California

• -sulfide minerals oxidized
• produces sulfate, metals, acidity (H)
• pH decreases
• reduced metals released, then oxidized
• mainly Fe(II) to Fe(III)
• metals precipitate as hydroxides (Fe(OH)3)
• hydroxide (OH-) consumed by metals
• pH decreases
• pH as low and lower than 3 recorded
• H 103
• H 103 M???

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vinegar
Iron Mountain, California
7
0
-4
pure water
acid rain
sea water
acid mine drainage
-3.6
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Concentration

• Mass per volume
• milligram per liter (mg L-1)
• microgram per liter (?g L-1)
• nanogram per liter (ng L-1)
• Moles per volume
• moles per liter (M)
• logarithmic scale
• pH -log H

Molarity M   moles of solute  or  M
mol                 1 Liter if
solution       L
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Concentration

• Mass per mass
• parts per thousand (per mil or O)
• parts per million (ppm)
• parts per billion (ppb)
• parts per trillion (ppt)
• 1000 milliliters (ml) in a liter (L),
• 1000 millimoles (mM) in a mole
• 1,000,000 micrograms (µg) in a gram.

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to Mg/L
You can memorize or set up a ratio. Its your
choice
Rule 1. to convert mg/L (ppm) to multiply by
0.0001
Rule 2. to convert to mg/L (ppm) multiply by
10,000
Rule 3. Ratio for percent to mg/L
Molarity    M   moles of solute      or    M
mol                    1 Liter if
solution                  L
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Solutions/Solids
A 1 NaCl solution is made by adding 1 g NaCl (a
solid) to enough water to equal a final volume of
100 ml. A 1 ethanol solution is made by
adding 1 ml ethanol (a liquid) to enough water to
equal a final volume of 100 ml To figure out how
much of a solid you need to make up a percent
solution
(mass/volume) (volume). EX How do you make
up 1 L of a 15 glucose solution? (15g
glucose/100 ml) 1000 ml 150 g glucose. You
would measure out 150 g glucose and then add
enough water to have a final volume of 1000 ml.
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Solutions/Liquid
To figure out how much of a liquid you need to
make up a percent solution (volume
material/volume solution) (total final volume).
For example How do you make up 0.3 L of a
15 ethanol solution? (15ml ethanol/100 ml)
300 ml 45 ml ethanol. You would measure out
45 ml of ethanol and then add water to a final
volume of 300 ml.
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Molar Solutions
When making up molar solutions from pure
starting materials, you need to know the weight
of a mole of the material, and the desired final
volume. For example, the following are some
molar weights Material Weight of 1
mole NaCl 58.5 g glucose 180 g CaCl2 111
g NaOH 40 g To figure out what mass of
material you need to make up a solution
(g/mole) (mole/L) L
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Molar Solutions
(g/mole) (mole/L)
L Examples To make 1 L of 1 M NaCl, you
need (58.5 g NaCl/mole) (1 M / L) 1 L 58.5
g NaCl. To prepare the solution, measure 58.5 g
of NaCl and add enough water so the final volume
is equal to 1 L. To make 300 ml of 10 mM CaCl2,
you need (111 g CaCl2/mole) (0.01 mole/L) 0.3
L .333 g CaCl2. To prepare the solution,
measure out 0.333 g CaCl2, and enough water so
that the final volume is 300 ml.
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Dilutions
The relationship between starting concentration,
final concentration, and dilution is Ci D
Cf where Ci initial concentration, Cf final
concentration, and D dilution. For example
How do you dilute a 1000 mM stock of glucose to
give you a final concentration of 10 mM? D
Cf/Ci 10 mM / 1000 mM 1/100. You need to
dilute the concentrated stock 1/100, so you could
mix 1 ml of your stock with 99 ml of
water.   Another example How do you dilute 70
ethanol to obtain 15 ethanol? D
Cf/Ci 15/70 15/70 You could take 15
ml of your stock and add 55 ml of water.
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M1V1M2V2
M1V1 M2V2 and solve for any quantity we wish
to. 1 is starting (concentrated) and 2 is
ending (dilute) For example suppose we want to
make 100 ml of a .10 M solution from a stock
solution of 6M strength Using the M1V1 M2V2
equation M1V1 M2V2 (100)(.10)    (x) (6) or
6x 10, x 1.67ml This means if we place 1.67
ml of the concentrated solution into a graduated
cylinder and add enough water to form 100 ml we
have the correct strength solution.
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Nightly Competition










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The objectives for this week to become familiar
with the fundamentals of water and its unique
chemical properties have been met.

1. Strongly Agree
2. Agree
3. Disagree
4. Strongly Disagree