maximum grams of solute that will dissolve in 100 g of solvent at a given temperature Varies with temperature Sugar is more soluble than salt

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2 maximum grams of solute that will dissolve in 100 g of solvent at a given temperature Varies with temperature Sugar is more soluble than salt

3 Solids are more soluble at... high temperatures. Gases are more soluble at... low temperatures & high pressures (Henry s Law).

4 Solutions are classified based on how much solute is present. Three types of solutions: Saturated Unsaturated Supersaturated

5 Contains maximum amount of solute that solvent can hold at a given temperature. filled with solute If more solute is added to saturated solution, it will not dissolve.

6 Solution with less than the maximum amount of solute that can be dissolved.

7 Solution with more solute than it can normally hold at a given temperature. Very unstable Solubility is given at specific temperature-if solvent is heated above that temperature, more solute may dissolve, which allows solution to be supersaturated. Ex: carbonated water

8 UNSATURATED SOLUTION more solute dissolves SATURATED SOLUTION no more solute dissolves SUPERSATURATED SOLUTION becomes unstable, crystals form increasing concentration

solids saturated: solution has just right amt.

9 Solubility (grams of solute/100 g H 2 O) Solubility vs. Temperature for Solids Graph that shows the dependence of solubility on temperature KI NaNO 3 gases solids saturated: solution has just right amt. of solute; on line HCl KNO 3 NH 4 Cl unsaturated: solution could hold more solute; below line NH 3 KCl supersaturated: solution has too much solute dissolved in it; above the line NaCl KClO 3 SO

10 Solubility(g/100 g H 2 O) 150 Saturated A single crystal of sodium acetate, NaC 2 H 3 O 2, is dropped into a supersatureated solution The small crystal causes extensive crystallization, and eventually Temperature ( o C) the solute forms a solid mass of NaC 2 H 3 O 2. Charles H.Corwin, Introductory Chemistry 2005, page 378

11 Solubility how much solute dissolves in a given amt. of solvent at a given temp. SOLUBILITY CURVE KNO 3 (s) Solubility (g/100 g H 2 O) KCl (s) HCl (g) Temp. ( o C) unsaturated: solution could hold more solute; below line saturated: solution has just right amt. of solute; on line supersaturated: solution has too much solute dissolved in it; above the line

12 There are a few types of questions you need to be prepared to answer by reading a solubility curve. One question type has to do with temperature. *Question: At what temperature will 60 grams of potassium nitrate (KNO3) in 100 grams of water form a saturated solution? What are we looking for? temperature Step 1 find 60 grams on the y-axis. Grams are always on the y-axis of a solubility curve. Step 2 Move horizontally until you hit the solubility curve of the substance Step 3 Move straight down unit you find the temperature value on the x-axis In this example, the answer would be about 38 ⁰C.

13 Another type of question you need to be prepared to answer by reading a solubility curve is one that deals with solubility level (saturated, unsaturated or supersaturated). *Question: What type of solution is formed when 80 grams of potassium nitrate (KNO3) is dissolved at 40⁰C? What are we looking for? Is the solution saturated, unsaturated or supersaturated. Step 1 plot the point given on the graph. Step 2 Where is the point in relation to the solubility curve? Answer: The point is above the line so that means this point would show a supersaturated solution

Another type of question you need to be prepared to answer by reading a solubility curve is one that deals with two substances having the same solubility.

14 Another type of question you need to be prepared to answer by reading a solubility curve is one that deals with two substances having the same solubility. *Question: At what temperature will KNO3 and KBr have the same solubility? What are we looking for? At what temperature will the solubility curves for KNO3 and KBr cross? Step 1 find the point where the lines for the substances in the question cross. Step 2 Move down to temperature on the x-axis to find the value. Answer: These points cross at the value in between 40 ⁰C and 60 ⁰C which would be 50 ⁰C

15 Polarity of the Solvent Temperature Pressure

16 like dissolves like Solutions are more likely to form when solute and solvent are either both polar or both nonpolar. Oil does not dissolve in water because oil is nonpolar and water is polar.

17 The solubility of solids increases as the temperature of the solvent increases Gases become less soluble as temperature of solvent increases

18 Increasing the pressure on a gas increases its solubility in a liquid.

19 Concentration of a solution is the amount of solute dissolved in specified amount of solution. Concentration can be expressed as: Percent by volume Percent by mass Molarity

Worksheet: Solubility

Worksheet: Solubility 1. According to your Reference Tables, which substance forms an unsaturated solution when 80 grams of the substance is dissolved in 100 grams of H 2 O at 10 C? (A) KI (B) KNO 3 (C) NaNO 3 (D) NaCl 2. The