Pure Substance A material consisting of only one type of element or compound Mixture A collection of two or more pure substance that can be separated by physical means Mixtures Homogeneous all samples of the mixture have the same ratio of components Heterogeneous different components can be seen as individual substances Chapter 16 Most materials are mixtures Mixtures Homogeneous Mixtures Composition is the same throughout Solution all components are in the same phase which may be any phase Suspension there are different phases present Concentration of Solution The amount of solute in solution Milligrams of solute per liter of solution 1 part solute Solution A homogeneous mixture consisting of ions or molecules Solvent the major component Solute the minor components Saturated no more solute will dissolve in the solvent Parts per million Solute Concentration Solutions 1 ppm 1 milligram solute 1 000 000 parts solution 1 liter solution Number of Molecules 602 billion trillion 602 000 000 000 000 000 000 000 6 02 x 1023 A mole of molecules Measured in Grams per liter Parts per million ppm of molecules per liter M 1 Mole of atoms 6 02 x 1023 Atomic mass is number of grams of a mole of atoms Or molecular mass of a molecule is number of grams of molecules Formula Mass Mass of a mole of atoms or molecules Carbon C 12 Oxygen O2 32 Carbon dioxide CO2 44 Sucrose C12H22O11 342 Oxygen Solubility Solubility Oxygen solubility Moles of solute per liter of solution 1 M sucrose solution Solubility factors 0 016 g oxygen L water Ability of solute to dissolve in a solvent Often temperature dependent Molarity Temperature of substances Types of molecules 0 014 0 012 Polar molecules are soluble in polar solvents Nonpolar molecules are soluble in nonpolar solvents 0 01 0 008 0 006 0 10 20 30 40 Acidity of solvent especially for polar molecules Temperature degrees C Insoluble Does not dissolve to any appreciable extent in the solvent Salt is insoluble in oil Salt is soluble in water Precipitate Solute that comes out of solution Often caused by change in temperature Soap Non polar and polar properties Polar part attracts water CH chain Non polar part attracts grime NaCO2 2 Soap and grime Detergent Stronger grease penetration Lower cost of production Sulfate or sulfonate group attached to CH chain Cleaning in Hard Water Ions of Ca2 or Mg2 ions bond to the polar end of the cleansing compound and reduce the quantity available for cleaning Detergent mixtures often contain Na2CO3 to bond with the Ca2 and Mg2 ions Purifying the Water We Drink The first step to purifying water is removing particles and bacteria Home water softeners Hard Water Contains Mg and or Ca ionic compounds Less soluble than Na ionic compounds Leave scale in pipes and on surfaces Ion Exchange resin Ion exchange resin Charge with salt NaCl to have Na ions available to treat hard water Water ions attracted to resin and exchange the Na ions for its Ca2 or Mg2 ions Purifying the Water We Drink Water is then aerated to improve the taste and smell Lastly the water is disinfected with chlorine gas or ozone Purifying the Water We Drink Sea water can be converted to drinking water through desalination Distillation Reverse osmosis 3 Distillation Osmosis Reverse Osmosis Wastewater Treatment Primary Wastewater Treatment Secondary Wastewater Treatment Screening removes large insoluble items Primary treatment allows smaller insolubles to settle to the bottom or rise to the top for removal Secondary treatment aerates the water and allows finer particles to settle for removal Tertiary treatment filters the water 4
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