Solutions

Forming Solutions Solution Solvent Solute Aqueous solution A homogeneous mixture Solvent The substance that does the dissolving Solute The substance that gets dissolved Aqueous solution A substance with water as a solvent

Solution Composition Saturated Unsaturated Supersaturated A solution that contains as much solute as will dissolve at that temperature Unsaturated A solution in which more solute can dissolve than is dissolved already at that temperature Supersaturated A solution that contains more solute than a saturated solution will hold at that temperature

Solution Composition continued Concentrated A solution in which a relatively large amount of solute is dissolved in a solution. Dilute A solution in which a relatively small amount of solute is dissolved in a solution.

Factors that Affect the Rate of Dissolving Three factors that affect the speed of the dissolving process Surface area Stirring Temperature

Molarity Sometimes referred to as the concentration of a solution M = molarity = moles of solute = mol liters of solution L

Adding 1. 0 mole of solute to 1. 0L of water does not make a 1 Adding 1.0 mole of solute to 1.0L of water does not make a 1.0M solution. Why not?

Calculating Molarity, I Calculate the molarity of a solution prepared by dissolving 11.5 g of solid NaOH in enough water to make 1.50 L of solution. 11.5g NaOH 1 mol NaOH = 0.288 mol NaOH = 1.50 L solution 0.288 mol NaOH 40.00 g NaOH 0.192 M NaOH

Calculating Molarity, II Calculate the molarity of a solution prepared by dissolving 1.56g of gaseous HCl into enough water to make 26.8mL of solution. 1.56 g HCL 1 mol HCl = 36.46 g HCl 26.8 mL 1L = 1000 mL 0.0427 mol HCl = 0.0268 L 0.0427 mol HCl 0.0268 L 1.59 M HCl

Example 15.7 To analyze the alcohol content of a certain substance, a chemist needs 1.00L of an aqueous 0.200M K2Cr2O7 (potassium dichromate) solution. How much solid K2Cr2O7 (molar mass 294.2 g/mol) must be weighed out to make this solution? 1.00L x 0.200mol K2Cr2O7 = L 0.200 mol K2Cr2O7 x 294.2 g K2Cr2O7 = mol K2Cr2O7 0.200 mol K2Cr2O7 58.8 g K2Cr2O7