water

CHEM 103/ WaterCHEM 103/ Water

•Unusual Properties:Unusual Properties:•High heat capacity - retains High heat capacity - retains

heat wellheat well•High boiling and melting High boiling and melting

point, but low formula point, but low formula weight.weight.

•Dissolves polar substances.Dissolves polar substances.1

water

CHEM 103/ WaterCHEM 103/ Water

•Hydrogen Bonds: a weak Hydrogen Bonds: a weak bond between the H of one bond between the H of one water molecule and the O of a water molecule and the O of a second water molecule.second water molecule.

• This bond needs 10 Kcal/mole This bond needs 10 Kcal/mole to break; a regular ionic or to break; a regular ionic or covalent bond needs 100 Kcal covalent bond needs 100 Kcal to break to break

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CHEM 103/ WaterCHEM 103/ Water

• In General: In General: • Ionic bonds form between Ionic bonds form between

metals and nonmetalsmetals and nonmetals•Covalent bonds form Covalent bonds form

between nonmetalsbetween nonmetals•Metallic bonds form Metallic bonds form

between metal atomsbetween metal atoms3

water

CHEM 103/ WaterCHEM 103/ Water

•Polar substances dissolve Polar substances dissolve polar substances; nonpolar polar substances; nonpolar substances dissolve substances dissolve nonpolar substances.nonpolar substances.

•All ionic bonded substances All ionic bonded substances are polar; some covalent are polar; some covalent substances are polar.substances are polar.

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CHEM 103/ WaterCHEM 103/ Water

•Water can dissolve polar Water can dissolve polar covalent substances. If a covalent substances. If a substance dissolves in water substance dissolves in water but does not conduct electricity but does not conduct electricity it is polar covalent.it is polar covalent.

•We will try alcohol and salt.We will try alcohol and salt.•Classify these substances Classify these substances

based on your data. based on your data.

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CHEM 103/ WaterCHEM 103/ Water

•Water/solid (ice) is one of very Water/solid (ice) is one of very few substances that is less few substances that is less dense than the liquid - ice dense than the liquid - ice floats on water. (1 movie floats on water. (1 movie Titanic) Titanic)

•Water:Water:• controls climate (El Niño)controls climate (El Niño)• is purified by evaporation/rainis purified by evaporation/rain

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CHEM 103/ WaterCHEM 103/ Water

• Two problems we need to Two problems we need to approach: approach:

• 1. Drinking water1. Drinking water• 2. Waste water2. Waste water

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CHEM 103/ WaterCHEM 103/ Water

•Drinking water is purified Drinking water is purified by filtration, settling, and by filtration, settling, and addition of ozone and/or addition of ozone and/or chlorine to destroy chlorine to destroy microorganismsmicroorganisms

• Lime is added to raise pH Lime is added to raise pH (in Oneonta)(in Oneonta)

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water

CHEM 103/ WaterCHEM 103/ Water

•Waste water:Waste water:•Primary treatment; mainly Primary treatment; mainly

settling out of solidssettling out of solids•Secondary treatment: settling Secondary treatment: settling

out solids with treatment of the out solids with treatment of the solids to remove more sewagesolids to remove more sewage

• Tertiary: custom chemical Tertiary: custom chemical treatment treatment

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water

water

CHEM 103/ WaterCHEM 103/ Water

• Tertiary treatment requires a Tertiary treatment requires a thorough evaluation of the thorough evaluation of the waste water components. waste water components. Then appropriate chemical Then appropriate chemical agents are added to remove agents are added to remove the offending pollutants. the offending pollutants.

•On board: phosphate removalOn board: phosphate removal

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water

CHEM 103/ WaterCHEM 103/ Water

• Eutrophication of water bodiesEutrophication of water bodies• Eutrophication is characterized Eutrophication is characterized

by anoxic (low oxygen) by anoxic (low oxygen) conditions. Vast areas of Long conditions. Vast areas of Long Island Sound, and many lakes Island Sound, and many lakes are anoxic at times.are anoxic at times.

•Problem is overfertilizing the Problem is overfertilizing the water bodywater body

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Eutrophication or Water Eutrophication or Water Body DeathBody Death

• The main problems in The main problems in fertilization are C (organic fertilization are C (organic matter-sometimes sewage), N matter-sometimes sewage), N (as nitrate), P (as phosphate)(as nitrate), P (as phosphate)

• In fresh water P is the limiting In fresh water P is the limiting reagent- control P and you reagent- control P and you control plant growth and control plant growth and Eutrophication.Eutrophication.

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water

EutrophicationEutrophication•N is the limiting reagent in salt N is the limiting reagent in salt

water- L.I.Sound, Chesapeake water- L.I.Sound, Chesapeake Bay. Bay.

• Tertiary treatment removes P Tertiary treatment removes P and/or N. and/or N.

• Farming practices are adjustedFarming practices are adjusted•Still to do - fertilizers on lawns Still to do - fertilizers on lawns

& golf courses!& golf courses!

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CHEM103/Eutrophication/CHEM103/Eutrophication/Phosphate/Image Phosphate/Image

The upper lake is loadedThe upper lake is loadedwith algae from phosphatewith algae from phosphateOverload.Overload.

water

CHEM103/Example:Md CHEM103/Example:Md Coast & Chicken S***Coast & Chicken S***

• Maryland’s Eastern Shore is home to both Maryland’s Eastern Shore is home to both Tyson & Perdue- therefore 300 million Tyson & Perdue- therefore 300 million chickens.chickens.

• Their wastes amount to 720 million pounds Their wastes amount to 720 million pounds (convert to Kg).(convert to Kg).

• This provides as much P as the ENTIRE This provides as much P as the ENTIRE population of New York City. Also, as much population of New York City. Also, as much N as twice the population of L.A. Close to N as twice the population of L.A. Close to 1/2 of the N & P entering Chesapeake Bay 1/2 of the N & P entering Chesapeake Bay comes from this source. Ref: Rasicot, Julie, comes from this source. Ref: Rasicot, Julie, AMC OutdoorsAMC Outdoors, Mar., ‘99, p. 19. , Mar., ‘99, p. 19.

water

CHEM103/Carbon Dioxide CHEM103/Carbon Dioxide & Water& Water

• Equilibrium- In chemistry an Equilibrium- In chemistry an equilibrium is established equilibrium is established when the forward reaction when the forward reaction is at the same rate as the is at the same rate as the reverse reaction: A + B reverse reaction: A + B <=> C + D. <=> C + D.

water

CHEM 103/ Carbon dioxide CHEM 103/ Carbon dioxide & Water.& Water.

• For COFor CO22 + H + H22O = HO = H22COCO33

• The carbonic acid makes the The carbonic acid makes the water acidic. If the solution is water acidic. If the solution is warmed, carbon dioxide warmed, carbon dioxide becomes less soluble, and to becomes less soluble, and to maintain the equilibrium, maintain the equilibrium, carbonic acid decomposes to carbonic acid decomposes to carbon dioxide and water.carbon dioxide and water.

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CHEM103/ Equil.CHEM103/ Equil.

• Therefore the acidity goes Therefore the acidity goes down. DEMO.down. DEMO.