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 (SOLUTIONS) 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

CuSO 4 (aq) Which is a solution & how do you know?

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

FINDING CONCENTRAION: We can measure how much HCl, NaHCO 3, PbNO 3 is mixed with the water…

Concentration: measurement that describes how much solute is in given amount of solvent or solution NOTE: Many, many different units to express concentration - Pick the unit by the task at handNOTE: Many, many different units to express concentration - Pick the unit by the task at hand

Percent By mass mass (solute) x 100% mass (solution) By volume volume (solute) x 100% volume (solution)

Mass solution = Mass solute + Mass solvent

PPM (parts per million) PPM = grams solute X 1,000,000PPM = grams solute X 1,000,000 used when solute is present in very small amounts (The Regents don’t follow this rule)used when solute is present in very small amounts (The Regents don’t follow this rule) like % except you multiply by 1,000,000 instead of 100 grams solution

LET’S PRACTICE: 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] What is the solvent? Water How much solvent is there? 100 mL = 100 g How much solute is there? g How much is the total solution? 100 g g = g

LET’S PRACTICE: About g of O 2 can be dissolved in 100 mL of water at 20 o C. Express in ppm. THE EQUATION ppm = g X 1,000, g ppm = 43 ppm [Memorize: 1 mL water has mass of 1 g]

NOW YOU TRY: 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

HERE’S ANOTHER: 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

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