Chemistry 20 - Chapter 5 Solutions 5.5 Solubility

Saturated Solutions when no more solute will dissolve in the solvent at a specific temperature when no more solute will dissolve in the solvent at a specific temperature solubility - is defined as the concentration of a saturated solution in g/100ml solubility - is defined as the concentration of a saturated solution in g/100ml molar solubility - is solubility in mol/L molar solubility - is solubility in mol/L

Saturated Solutions Crystallization is one method we can use to determine solubility of a solid. Crystallization is one method we can use to determine solubility of a solid. » the solvent is removed from the solution leaving the solid. » the mass of the solid per unit of volume is then determined.

Solubility Rules solids have higher solubility as temp increases solids have higher solubility as temp increases »Think of dissolving sugar in cold KoolAid as compared to dissolving sugar in hot coffee

Solubility Rules gases have higher solubility as temp decreases gases have higher solubility as temp decreases »A can of pop opened and left at room temperature loses dissolved CO 2 and becomes flat

Solubility Rules some liquids are immiscible with water ie. form layers some liquids are immiscible with water ie. form layers »Oil and water

Solubility Rules cont. some liquids such as alcohols (polar) cannot form saturated solutions and are said to be miscible with water. some liquids such as alcohols (polar) cannot form saturated solutions and are said to be miscible with water. elements have low solubility except halogens and oxygen elements have low solubility except halogens and oxygen

Solubility Equilibrium at equilibrium there is no observable changes in a system at equilibrium there is no observable changes in a system at the molecular level the forward reaction and the reverse reaction are taking place at the same rate at the molecular level the forward reaction and the reverse reaction are taking place at the same rate

Solubility Equilibrium Example NaCl (s)NaCl (aq) In this equilibrium equation for a saturated solution, the forward reaction and the reverse reaction are occurring at the same rate. No change will be visible.

Assignment Read pages Read pages Do #29-32 Do #29-32 Do Lab Ex 5E Do Lab Ex 5E Pre-Lab for Inv 5.5 = problem, prediction, graph Pre-Lab for Inv 5.5 = problem, prediction, graph

Investigation 5.5 The Solubility of Sodium Chloride in Water Problem: Problem: Prediction: On graph paper - graph Table 5.5 Page 133 with Temperature as the Manipulated Variable. Prediction: On graph paper - graph Table 5.5 Page 133 with Temperature as the Manipulated Variable.

Investigation 5.5 Evidence: Evidence: »Read through the procedure and determine what measurements you will be making. Prepare a table to record your evidence.

Investigation 5-5 Title Title Problem Problem Prediction - prepare a graph of Table 5.5 page 133. Temperature is the manipulated variable. Measure the temp. and predict the solubility based on the graph. Prediction - prepare a graph of Table 5.5 page 133. Temperature is the manipulated variable. Measure the temp. and predict the solubility based on the graph.

Investigation 5-5 Evidence Evidence »Volume of saturated sol’n ________ »Solution Temperature ______ »Mass of evaporating dish __________ »Mass of dish and contents __________

Investigation 5-5 Analysis - do all calculations here. Analysis - do all calculations here. »Convert your g/10mL into g/100 mL »Write a concluding statement - see Analysis page 523 for an example of the statement.

Investigation 5-5 Evaluation (paragraphs) Evaluation (paragraphs) experimental design experimental design procedure procedure technological skills technological skills overall evaluation overall evaluation percent difference (pg 524) percent difference (pg 524) judgement of prediction judgement of prediction

Investigation 5-5 »Complete the Analysis and Evaluation sections of the lab. »Complete WS #25 and hand it in with your lab. »Overview - Summary, Keywords defined, Questions 1-32 and Lab Exercise 5E for Wednesday

Assignment Read pages Read pages Do #33-35 Do #33-35 Do Overview Do Overview Do Worksheet #25 Do Worksheet #25