Solutions!

Classification of Matter Matter Pure Substanc es Mixtures HomogeneousMixturesHeterogeneousMixturesElementsCompounds

Heterogeneous Mixtures See visibly different regionsSee visibly different regions –Granite –Dirt –Cereals –Oil & Vinegar See a boundarySee a boundary –Ice cube in water

Homogeneous Mixtures Particles very small – on atomic scaleParticles very small – on atomic scale –Can’t see particles –Can’t sort particles –Can’t get trapped by filter –Can’t scatter light Particles evenly distributedParticles evenly distributed Particles do not separateParticles do not separate

Solution Homogeneous mixture of 2 or more substances in a single physical state (phase)

Parts of a Solution SoluteSolute = substance being dissolved SolventSolvent = dispersing medium that substance is being dissolved in

Identify the solute and solvent in each picture

Solute = ? Solvent = ?

Hints to identify solute & solvent SoluteSolute: –substance that changes phase –substance that have less of SolvenSolvent: –substance that maintains phase –substance that have more of

Aqueous Solutions WaterWater is solvent Transition metalsTransition metals form brightly colored solutions

Solutions occur in all 3 phases! Alloys: Brass, etc. SolidSolid Fillings: Hg in Ag SolidLiquid H 2 in Pd metal SolidGas Salt water LiquidSolid Antifreeze in radiator LiquidLiquid Seltzer Water LiquidGas MothballsGasSolid Water Vapor in Air GasLiquid AirGasGas ExampleSolventSolute

Gas in a liquid: CO 2 in and out of water Bubbles mean it ’ s a mixture not a solution!

Concentration of Solutions

Concentration measurement that describesmeasurement that describes how much solute in given amount of how much solute in given amount of solvent or solution solvent or solution express concentration using many, many different unitsexpress concentration using many, many different units –pick the unit according to task at hand

Percent By mass By Volume % = Part x 100 Whole

Twists sometimes ask for part or whole, not percent sometimes give volume/mass of solution sometimes give volume/mass of solvent and volume/mass of solute Mass solution = Mass solute + Mass solvent

ppm (parts per million) used when solute is present in very small amountsused when solute is present in very small amounts (Regents board doesn’t follow this rule) (Regents board doesn’t follow this rule)

ppm (parts per million) ppm = grams solute x 1,000,000 ppm is ratio between mass solute & mass soln like % except you multiply by 1,000,000 instead of 100 grams solution

About g of O 2 can be dissolved in 100 mL of water at 20 o C. Express in ppm. [Memorize: 1 mL water has mass of 1 g] ppm = g x 1,000, = 43 ppm

CO 2 gas has solubility of g/100 g water at 40 o C. Express in parts per million. ppm = g solute x 1,000, g solution = 971 ppm

What is the concentration in ppm of a solution with 30.0 g NaNO 3 in 70.0 g water? ppm = 30.0 g NaNO 3 x 1,000, g solution = 300,000 = 3.0 X 10 5 ppm

How many grams of KOH are needed to be dissolved in water to make grams of a 10.0 ppm solution? 10 ppm = ? grams KOH X 1,000, g solution ? = 0.02 grams KOH