Chapter 7A- Solutions p. 117-123

Properties of solutions Solutions are homogeneous mixtures of substances in the same physical state Contain atoms, ions, or molecules of one substance spread uniformly throughout a second substance. Characteristics of liquid solutions: Solutions are clear and do not disperse light. Can have a color Will not settle on standing Will pass through a filter

Components of a solution SOLUTE: substance being dissolved present in a smaller amount SOLVENT: substance doing the dissolving Present in a greater amount

Factors that Affect Solubility Solubility = how much of a solute will dissolve in a certain amount of solvent at a particular temperature Temperate Pressure (ONLY FOR GASES) Nature of solute/solvent

Temperature TABLE G SOLIDS GASES As temperature increases, solubility increases GASES As temperature increases, solubility decreases

pressure Only effects gases! As pressure increases, solubility increases

Nature of Solute/Solvent “Like dissolves like.” Non-polar solute dissolves in non-polar solvent Polar solute dissolves in polar solvent This is why certain things won’t dissolve in water. Water is ____.

Solubility Curves (Table G) Table G demonstrates the relationship between grams of solute that can be dissolved as temperature increases. Solids – the positive slope. Increasing lines. Gases- the negative slopes. Decreasing lines. SO2, HCl, NH3

Solubility UNSATURATED A solution that holds less solute than the maximum it can hold BELOW the solubility line Dilute solution SATURATED A solution that contains the maximum amount of solute that will dissolve at a specific temperature ON the line SUPERSATURATED A solution that contains more solute than is present in a saturated solution ABOVE the line Concentrated solution

Examples A solution contains 35g of KNO3 dissolved in 100g of water at 40oC. How much more KNO3 would have to be added to make a saturated solution? A solution containing 90g of KNO3 per 100. grams of H2O at 50oC is considered to be (concentrated/dilute) and (supersaturated/saturated/unsaturated). A solution containing 55g of NH4Cl in 100g of water is saturated at a temperature of what?

Table G is based on 100g of water If there is a question that asks you to find the solubility in 200 g of water: Multiply answer by 2. If there is a question that asks you to find the solubility in 300 g of water: Multiply answer by 3. If there is a question that asks you to find the solubility in 50 g of water: Divide answer by 2.

Examples What is the maximum number of grams of KCl that will dissolve in 200g of water at 50oC to produce a saturated solution? What is the total number of grams of potassium chloride needed to saturate exactly 300g of water at 10oC? How many grams of KNO3 are needed to saturate 50. grams of water at 70oC?

Solutions and Precipitate When a solute comes out of solution, It is called a precipitate If it is a gas, it will escape out the top Such as CO2 leaving a soda bottle If it is a solid, it will settle to the bottom Such as too much sugar in your tea 100g of water is saturated with NH4CL at 50oC. If the temperature is lowered to 10oC, what is the total amount of NH4Cl that will precipitate?

Solubility Tables- Table F A solution is SOLUBLE when it dissolves completely A solution is INSOLUBLE when it does not dissolve completely and forms a precipitate Based on Table F

Examples: Which of these salts is LEAST soluble in water? PbCl2 C. FeCl2 LiCl D. RbCl Which compound is the MOST soluble? Silver iodide C. Silver Bromide Silver chloride D. Silver Acetate Which compound is the LEAST soluble? Ca(OH)2 C. LiOH Ba(OH)2 D. Sr(OH)2

Open your workbooks to p. 120-121 (1-12) 4 2 3 2 1 3

Now, p. 123 (13-23) 2 2 or 4 H h F f