SOLUTIONS

Homogeneous mixture containing two or more substance called the solute and the solvent. SOLUTE: Substance that is dissolved (lower quantity). SOLVENT: Dissolving medium (higher quantity).

TYPES OF SOLUTIONS SOLUBLE: Substance that dissolve in a solvent (sugar or salt) INSOLUBLE: Substance that do not dissolve in solvent oil or sand INMISIBLE: Both liquids and can not be mixed MISIBLE: Both liquids and can be mixed

SOLVATION The process of surrounding solute particles with solvent particles in water is called solvation. Temperature agitation and more quantity of solute can raise the rate of solubility.

SOLUBILITY Maximum amount of solute that will dissolved in a given amount of solvent at a specified temperature and pressure. Solubility is usually expressed in grams of solute per 100 grams of solvent. Saturated solution Unsaturated solution Supersaturated solution

SOLUTION CONCENTRATION CONCENTRATION.- Measure of how much solute is dissolved in a specific amount of solvent or solution. Qualitative Dilute Concentrate

SOLUTION CONCENTRATION Quantitative Percent by mass mass solute X 100 mass solution Percent by volume Volume solute X100 Volume solution Molarity Mol of solute Liter of solution Molality Moles of solute Kg of solvent Mole fraction Moles of solute Moles of solute + moles of solvent

PERCENT BY MASS The percent by mass is the ratio of the solute’s mass to the solution’s mass expressed as a percent. The mass of the solution equals the sum of the masses of the solute and the solvent. Usually describes a solid dissolved in a liquid!

EXAMPLE: Percent by mass In order to maintain a sodium chloride (NaCl) concentration similar to ocean water, an aquarium most contain 3.6 g NaCl per 100 g of water. What is the percent by mass of NaCl in the solution?

CLASSWORK Solve problems 8, 9 and 10 of Practice Problems page 463.

PERCENT BY VOLUME Is the ratio of the volume of the solute to the volume of the solution expressed as a percent. The volume of the solution is the sum of the volumes of the solute and the solvent. Usually describes a liquid dissolved in a liquid!

EXAMPLE: Percent by volume What is the percent by volume of ethanol in a solution that contains 35 ml of ethanol, dissolved in 115 ml of water?

CLASSWORK Solve problems 11, 12 and 13 of Practice problems page 464.

MOLARITY.. Is the number of moles of solute dissolved per liter of solution. Also known as molar concentration. 1L 1 mol

EXAMPLE: Molarity Calculate molarity of 100 ml of aqueous solution containing moles of dissolved potassium chloride KCl.

CLASSWORK Solve problems 14, of Practice problems page 465.

MOLALITY Is the ratio of the number of moles of solute dissolved in one kilogram of solvent. 1 mol 1 kg

Molality In the lab a student add 4.5 moles of sodium chloride NaCl to 100 g of water. Calculate the molality of the solution.

CLASSWORK Solve problems 24 and 25 of Practice Problems page 469.

MOLE FRACTION Is the ratio of the number of moles of solute in solution to the total number of moles of solute and solvent. Where nA is the number of moles of solute and nB the number of moles of solvent. 1 mol A Mol of B

Mole fraction Calculate the mole fraction of hydrochloric acid HCl in the aqueous solution. For every 100 g of solution, 37.5 g would be HCl and 62.5 g would be the water.

CLASSWORK Solve problems 26 and 27 of Practice problems page 470.

pH Is a measure of the acidity or basicity of a solution. It is defined as the cologarithm of the activity of dissolved hydrogen ions (H+). The pH scale is not an absolute scale; it is relative to a set of standard solutions whose pH is established by international agreement

[H 3 O + ] moles/liter pHp0H 10 0 =1014Very acidic Weakly acidic Neutral Weakly basic Very basic

Formulas pH= -log [H+] pOH= -log [OH-] pH+POH= 14

Practice problems The concentration of either the H + ion or the OH - ion is given, calculate [H + ] and te or [OH - ]. State whether the solution is acidic, basic, or neutral. a) [H + ]= 1.0 X M b) [OH - ]= 1.0 X M c) [OH - ]= 1.0 X M

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