UNIT 1: WATER:
EXPLORING SOLUTIONS
MISS SHUEY
CHEM COMM
ESSENTIAL QUESTIONS
• What techniques can we use to purify water?
• What are the physical properties of water?
• Why do some substances readily dissolve in water
and others do not?
• How does chemistry contribute to effective water
treatment?
ARTICLE REVIEW
• Fish Kill Triggers Riverwood Water Emergency
SECTION A: SOURCES AND USES OF
WATER
• Uses of water:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
_________________________
_________________________
_________________________
_________________________
_________________________
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A.4 WATER SUPPLY AND DEMAND
• Family of four uses 390 gallons daily.
• Direct water use – volume that can be directly
measured.
• Indirect water use – hidden uses of water that you
may never have considered.
• Ex. Slice of pizza??
Figure 1.12
A5. WATER USE IN THE US
• For each region in the US, name the greatest single
use of water.
• A. the east
b. the south c. the midwest
• D. the west
e. alaska
f. hawaii
Explain the differences in how water is used in the east and
the west. Think about where most people live and where
most of the nation’s factories and farms are located. What
other regional factors help explain the general patterns of
water use?
List two factors about the weather, economy, or culture that
could explain the greatest water use within each of these six
U.S. regions.
A.6 WHERE IS THE WORLD’S WATER?
• 97% of the world’s water.
1. Ocean
2. Glaciers
PHYSICAL STATES OF WATER
• Gaseous state: water vapor
• Liquid state: lakes, rivers, oceans, clouds, and rain.
• Solid state: ice
CITY WATER
• Surface water: water supply originated in a river or
other body of water.
• Ground water: water in a well.
RURAL WATER
• Aquifer: water-bearing layer of rock, sand, or
gravel, then pumped to the surface.
A.8 RIVERWOOD WATER USE
• Pg.22
• http://www.youtube.com/watch?v=xxNfJLMNS4E&li
st=FLHywkjQDas46hk_l2QAeKaA&feature=mh_lolz
SCIENTIFIC METHOD
Hypothesis – testable statement
controls – remain constant
variable – is changed
Model – explanation of how phenomena occur and
how data or events are related.
Theory – broad generalization that explains a body of
facts or phenomena.
ACCURACY AND PRECISION
• Accuracy – close to the expected value
• Precision – a number of measurements close to
each other.
What is more accurate?
Graduated cylinder
Or
Beaker
SIGNIFICANT FIGURES
• Indicates how precise a measurement is.
rule
example
1. Zeros between other nonzero a. 50.3 m has three sig figs
digits are significant
b. B. 3.0025 s has five sig figs
2. Zeros in front of nonzero
digits are not significant.
a. 0.892 kg has three sig figs
b. 0.0008 ms has one sig fig
3. Zeros that are at the end of
a number and also to the right
of the decimal are significant
a. 57.00 g has four sig figs
b. B. 2.000000 kg has seven sig figs
4. Zeros at the end of a
number but to the left of a
decimal are significant if they
have been measured or are
the first estimated digit; if not
they are NOT significant.
a. 1000 m may contain from one to four
sig figs, depending on the precision of
the measurement, in this book it will be
assumed there is one sig fig.
b. 20 m has one sig fig (scientific notation
will indicated sig fig number)
RULES FOR CALCULATING WITH SIG
FIGS
Type of calculation
Rule
example
Addition or subtraction
When measurements
are added or
subtracted, the answer
can contain no more
decimal places than
the least accurate
measurement
97.3
+ 5.85
--------103.15  103.2
Round off
Multiplication or division The final answer has the
123
same number of sig figs x
5.35
as the measurement
------------658.05  658
having the smallest
number of sig figs.
Round off
SIG FIG PRACTICE
Perform these calculations following the rules for sig
figs.
a. 26 x 0.02584 = ?
b. 15.3 / 1.1 = ?
c. 782.45 - 3.5328 = ?
d. 63.258 + 734.2 = ?
SI unit – measurements in science.
Volume
Density – m/v
A sample of aluminum metal has a mass of 8.4g. The
volume of the sample is 3.1 cm3. calculate the density
of aluminum.
Dimensional analysis – math technique that allows you
to use units to solve problems involving measurements.
SECTION B
• Article reading
• B.1 PHYSICAL PROPERTIES OF WATER
• Matter – anything that occupies space and has
mass.
• Physical properties: observed and measured
without changing the substance.
• Density – mass of material within a given volume.
• D = m/v
WATER PROPERTIES
• Freezing point – 0 C when liquid water forms a solid.
• Aqueous solution – water-based solution.
• Important aqueous solutions in your life:
• ____________________
• ____________________
• ____________________
B.3 MIXTURES AND SOLUTIONS
• Mixture – when two or more substances combine
and retain their individual properties.
• Heterogeneous (suspension)
• Homogeneous (solution)
• Solute
• Solvent
• Pg.30
B.4 PARTICULATE VIEW OF WATER
• Particulate level – at the level of its atoms and
molecules.
• Atoms – building blocks of matter.
• Element – matter made up of only one type of
atom.
• Compound – composed of the atoms of two or
more elements bonded together in fixed
proportions.
• Ex.
• Chemical formulas – representing compounds or
elements, showing ratios of how they bond.
• Ex.
• Substance – element or compound with uniform
and definite compositions.
• Molecule – smallest unit of a molecular compound
that retains the properties of that substance.
B.5 PICTURES IN THE MIND
• Macroscopic – large-scale, easily observed without
microscopes or other tools.
• Models – representations of atoms and molecules.
• Pg.33 ques. 1-7
B.6 SYMBOLS, FORMULAS, AND
EQUATIONS
• Chemical symbols – letters to represent element.
• Periodic table of the elements – arrangement of
elements according to the number of protons.
COMMON ELEMENTS
Aluminum Al
Bromine
Br
Calcium
Ca
Carbon
C
Chlorine
Cl
Cobalt
Co
Copper
Cu
Fluorine
F
Gold
Au
Phosphorus P
Silver
Ag
Sulfur
S
Hydrogen
Iodine
Iron
Lead
Magnesium
Mercury
Nickel
Nitrogen
Oxygen
Potassium
Sodium
Tin
H
I
Fe
Pb
Mg
Hg
Ni
N
O
K
Na
Sn
WHAT ELEMENT IS THIS?
K
potassium
WHAT ELEMENT IS THIS?
Al
aluminum
WHAT ELEMENT IS THIS?
Br
bromine
WHAT ELEMENT IS THIS?
Ca
calcium
WHAT ELEMENT IS THIS?
C
carbon
WHAT ELEMENT IS THIS?
Cl
Chlorine
WHAT ELEMENT IS THIS?
Co
Cobalt
WHAT ELEMENT IS THIS?
F
Fluorine
WHAT ELEMENT IS THIS?
Au
Gold
WHAT ELEMENT IS THIS?
H
Hydrogen
WHAT ELEMENT IS THIS?
I
Iodine
WHAT ELEMENT IS THIS?
Fe
Iron
WHAT ELEMENT IS THIS?
Pb
Lead
WHAT ELEMENT IS THIS?
Mg
Magnesium
WHAT ELEMENT IS THIS?
Hg
Mercury
WHAT ELEMENT IS THIS?
Ni
Nickel
WHAT ELEMENT IS THIS?
N
Nitrogen
WHAT ELEMENT IS THIS?
O
Oxygen
WHAT ELEMENT IS THIS?
P
Phosphorus
WHAT ELEMENT IS THIS?
Ag
Silver
WHAT ELEMENT IS THIS?
Na
Sodium
WHAT ELEMENT IS THIS?
S
Sulfur
WHAT ELEMENT IS THIS?
Sn
Tin
WHAT IS THE ATOMIC NUMBER?
O – Oxygen
8
WHAT IS THE ATOMIC NUMBER?
C – Carbon
6
WHAT IS THE ATOMIC NUMBER?
H–
Hydrogen
1
WHAT IS THE ATOMIC NUMBER?
Au – Gold
79
WHAT IS THE ATOMIC NUMBER?
N – Nitrogen
7
B.8 ELECTRICAL NATURE OF MATTER
• Electrons – negatively charged particles
• Protons – positively charged particles, in nucleus
• Neutrons – neutral particles, in nucleus
B.9 IONS AND IONIC COMPOUNDS
• Ions – electrically charged
atoms or groups of atoms.
• Ionic compounds –
substances composed of
positive and negative ions
• Cation – positive ion Na+
• Anion – negative ion Cl• Polyatomic ion – ion
consisting of a group of
bonded atoms
B.11 WATER TESTING
• Precipitate – insoluble material in water.
• Qualitative test – looking at non numerical
descriptions.
• Quantitative tests – numerical data.
• Ionic compounds
• Metal + nonmetal
B.12 PURE AND IMPURE WATER
• Pg. 45
• Gases in atmosphere dissolve in water, nitrogen,
oxygen, carbon dioxide
• 46-47 Read
SEC. C INVESTIGATING THE CAUSE OF
THE FISH KILL
• Solubility – substance that will dissolve in water.
• Saturated – maximum quantity of a substance that
will dissolve in a quantity of water.
• What effects solubility?
• Solubility curve –
relationship between
temperature and
solubility
• Unsaturated solution – solution that contains less
dissolved solute than the amount that the solvent
can normally hold at that temperature.
• Supersaturated solution – unstable solution that
contains more solute than could usually be
dissolved at that temperature.
• Ex. Rock candy (pg.55)
C.4 DISSOLVING IONIC COMPOUNDS
• Form ions in water
• Polar molecule – electrons are not evenly
distributed throughout its structure.
• Partial positive region and partial negative region.
• Ex. water
DIATOMICS
Reactant and Products are shown in chemical equations
Reactant are the substances that are used to make a
chemical reaction
Products are substances produced by the
reaction
Na + Cl ---> NaCl
reactant --> products
Diatomic Molecules - some elements bond to themselves,
like H2
GEN-U-INE diatomic molecules U should remember that
the diatomic molecules all end in -GEN or -INE
(or H
N F
O I C B)
H2 N2 F2 O2 I2 Cl2 Br2
C.8 INAPPROPRIATE HEAVY-METAL
ION CONCENTRATIONS?
• Essential Metal Ions:
•
•
•
•
Iron(II) Fe2+
Potassium K+
Calcium Ca2+
Magnesium Mg2+
Heavy-metal ions – atoms have greater masses than those of
essential metallic elements, harmful to humans and other
organisms.
• Lead Pb2+
-bind to proteins in biological systems,
• Hg2+
prevents proteins from performing their
normal task.
HEAVY METAL HARM
• Damage to the nervous system, brain, kidneys, and
liver, which can even led to death.
• They become concentrated within the bodies of
fish and shellfish.
• Costly to remove
• Hard to detect
• Prevention: using alternate materials in industry.
Called Green Chemistry
LEAD IONS (PB2+)
• Latin name – plumbum
• Plumber – water pipes in ancient Rome were
commonly made of lead.
• Used in:
• Pottery, automobile electrical storage batteries, solder,
cooking vessels, pesticides, and paints
Many were replaced with iron, copper or plastic materials.
1970s lead was added to gas to produce a better-burning
automobile fuel. Released in atmosphere.
MERCURY IONS HG2+
• Liquid at room temp
• Latin name = hydrargyrum, quicksilver or liquid silver
• Uses:
• Electrical conductor, thermometers, thermostats, hats, light
bulbs, pesticides
• Vapor is hazardous, absorbed through skin
CHEMICAL POSTER
C.9 INAPPROPRIATE PH LEVELS
• pH – measure and report the acidic, basic, or
chemically neutral character of a solution.
• Range = 0---14
• Neutral = 7
7> acidic
7<basic (alkaline solutions)
1pH unit = tenfold difference in acidity or alkalinity
pH 3 soft drinks, pH 2 lemon juice
Lemon juice is 10 time more acidic than soft drinks.
LITMUS PAPER
•
•
•
•
•
•
•
•
Indicator to show level of acidity or alkalinity.
Blue – basic
Red – acidic
Acidic and basic solutions conduct electricity.
What does this tell you?
Ions present in the solution.
Acids – release H+ ions
Bases – release OH- ions
NEUTRAL SUBSTANCES
• Sucrose, sodium chloride solutions = neutral
• Low pH in streams
• Fish-egg development is impaired
• Increase the concentrations of metal ions by leaching
metal ions from surrounding soil.
High pH in streams
•
alkaline solutions are able to dissolve organic materials,
including skin and scales
EPA REQUIREMENTS
• Drinking water be within the pH range of 6.5 – 8.5
• Fish can tolerate 5.0 – 9.0
• Did the pH change to kill all the fish?
C.10 INAPPROPRIATE MOLECULAR
SUBSTANCE CONCENTRATIONS
• Molecular substances – composed of molecules not
ions.
• Molecular substances can be harmful for aquatic
life.
• Examples: ethanol C2H5OH, succinic acid C4H6O4,
carbon dioxide CO2, oxygen gas O2
• What determines the solubility of a molecular
substance in water?
• Distribution of electrical charge within molecules.
• Electronegativity – ability of an element’s atoms to
attract shared electrons when bonding within a
compound.  causes e- to be unevenly distributed
among the atoms.
POLAR MOLECULE
•
•
•
•
Negative and positive side of a molecule.
“like dissolves like”
Polar dissolves polar
Nonpolar dissolves nonpolar
• Ex. Oils, soaps  soap attracts oils
C.11 SOLVENTS
• Soluble – will dissolve
• Insoluble – will not dissolve
C.12 INAPPROPRIATE DISSOLVED
OXYGEN LEVELS?
• As temperature goes up less oxygen is dissolved.
• Gas solubility in water is directly proportional to the
pressure of that gaseous substance on the liquid.
• Increase in water temperature affects fish by
decreasing the amount of dissolved oxygen in the
water and by increasing the oxygen consumption
of fish.