Colloids and Solutions in the EnvironmentColloids and Solutions in the EnvironmentColligative Properties ReviewOsmosisWhat are Colloids?Tyndall EffectWhy is the Sky Blue?Solutions and Dilutions in the EnvironmentGround Water Contamination in Central PennsylvaniaPractice ProblemMarcellus ShaleMarcellus ShaleMarcellus ShaleWater CrisisClimate Change and DroughtConverting Salt Water to Potable WaterPractice ProblemWhat You Should KnowColloids andSolutions in the EnvironmentCH110 FA10 SAS 1Late Drop Deadline: Friday, November 11thExam 3: Monday November 7thPrepare for Recitation November 10thALEKS Objective 11 due November 5thANGEL Quiz 11, November 6thNote the special due dates!Lecture 31: November 2ndLecture 32: November 4thLecture 33: November 7th(Review for Exam)Read: Ch. 13.5,13.6Additional Preparation: BLB 13: 9,58,61,69,75; Packet 13: 13-18CH110 FA10 SAS 2By the end of Today’s Lecture you should know:ColloidsTyndall EffectHydrophobic vs. HydrophilicReverse OsmosisKEY QUESTIONS: THE BIG PICTUREColloids and Solutions in the EnvironmentWhat effects does solute concentration have on the physical properties of liquids?What differences are there when the solutes do not form homogeneous mixtures?Remember: macroscopic properties come from microscopic originsWhat is the origin of colligativeproperties?How do the colligative properties of solutions impact the environment?How do colloids impact the environment?Colligative Properties ReviewCH110 FA10 SAS 3• Colligative properties are affected by the _______ of solute, not by __________• Addition of a non-volatile solute to a solvent lowers the vapor pressure• Addition of a non-volatile solute to a solvent depresses the freezing point and elevates the boiling point• Addition of a non-volatile solute to a solvent increases the osmotic pressureOsmosisCH110 FA11 SAS 4concentratedsolutionsemipermeablemembrane• movement continues until osmotic pressurebuilds up to stop itOsmosis: the net movement of _______toward the solution with _________ solute concentration.Osmotic Pressure: pure solvent-or-dilutesolutionWhat are Colloids?CH110 FA10 SAS 5homogeneous solution of moleculescolloidsheterogeneous mixtureInfluenced by gravity10–2000 nmNot influenced by gravity• Gravity does not cause particles to settle• between solution and heterogeneous mixture• particles are very large molecules or aggregates• defined by the size of the particles• phases are mutually insolubleParticle size largesmallColloids:Tyndall EffectCH110 FA10 SAS 6• Visible light passes through solutions without scattering (particles very small)• Atoms are 10-10m in size, and do scatter x-rays as a result• Visible light is scattered by colloids (400-700 nm similar to particle sizeTyndall Effect: Fog Left: a colloidWhy is the Sky Blue?CH110 FA10 SAS 7suncolloids scatter more blue than redRising or Setting SunMid-day SunSolutions and Dilutionsin the EnvironmentCH110 FA10 SAS 8Water on Earth• Total volume ~ 1.4 x 109km3= 1.4 x 1018m3= 1.4 x 1021L• 97% of water on earth is in oceans• 2.1 % of fresh water is frozen• < 1 % is potable fresh waterGround Water Contamination in Central PennsylvaniaCH110 FA10 SAS 9Acid Mine Drainage• Water draining from exposed limestone in surface mines or construction projects• Construction of I-99 in State College was delayed by “unforeseen” environmental impacts from the project• Sulfide salts of toxic heavy metals get into our drinking waterPractice ProblemCH110 FA10 SAS 10Arsenic levels as high as 12.4 g/ L H2O have been observed in acid mine drainage from mines in Pennsylvania. The EPA limit on arsenic in drinking water is 10 parts per billion. What final volume would 1 L of this contaminated water have to be diluted to in order to be considered safe to consume? [For simplicity, assume a density of 1 g/mL]Marcellus ShaleCH110 FA10 SAS 11What are the potential surface water impacts from natural gas development?As of March 2011, 1.605 billion gallons of water have been used for fracturing.Bradford, Clearfield, Sesquehanna, and Washington counties have already reported significant release incidents.As a society, we must develop energy resources …Marcellus ShaleCH110 FA10 SAS 12Potential Hazards from Flowback:chloride 5-150 g/Lsodium 2-75 g/Lbarium 2-5 g/Lstrontium 1-7 g/Lbromide < 2 g/Lradium-226 100-16,000 pCi/LFlowback is also very acidicFracturing Chemical Mixtures:Marcellus ShaleCH110 FA10 SAS 13Better solutions for water sourcingBetter solutions for water storage, recycling, and decontaminationEPA has mandated tougher off-site treatment standardsSolutions, innovations, and outlook:Penn State Leadership:www.marcellus.psu.eduWater CrisisCH110 FA10 SAS 14• ~ 16% of the world lacks access to potable water• As the world’s population grows, this problem is expected to increase• Recent changes in climate are putting additional stress on fresh water suppliesClimate Change and DroughtCH110 FA10 SAS 15Lake Lanier, Georgia 2008Converting Salt Water to Potable WaterCH110 FA10 SAS 16• Distillation• Vaporization & condensation of water• Under reduced pressure• Reverse OsmosisUp to 8 MPaApplied pressure must be greater than ________________Practice ProblemCH110 FA10 SAS 17A reverse osmosis plant is set up near a body of salt water containing 1.2 M total solute. If the plant is regulated at 25oC, what is the minimum pressure that must be applied to force flow in the system into the pure water side of the semi-permeable membrane?What You Should Know CH110 FA10 SAS 18Colligative Properties• What are colligative properties and what do they depend on?• Do colligative properties matter in the environment?Colloids• What is the difference between a colloid and a homogeneous solution?• What are some common natural and anthropogenic colloids?• What is the tyndall effect?Solutions in the Environment• Do we have enough fresh water?• What is reverse
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