1. Solubility Honors Chemistry Mrs. Jacobus

2. Components of a Solution  Solute is the substance being dissolved – powder  Solvent is the dissolving agent – water Solute Solvent Dissolve

3. Solubility The amount of solute that will dissolve in a given amount of solvent. Soluble vs. insoluble  May vary with solvent  “Like dissolves like”

4. Polar and Nonpolar A polar bond is a covalent bond between two atoms where the electrons forming the bond are unequally distributed A nonpolar bond is a covalent bond between two atoms where the electrons forming the bond are equally distributed Nonpolar Molecule (CH 4 ) Polar Molecule (H 2 O)

5. “Like dissolves like” Two substances with similar intermolecular forces (force between two molecules) are likely to be soluble in each other. non-polar molecules are soluble in non-polar solvents CCl 4 in C 6 H 6 polar molecules are soluble in polar solvents C 2 H 5 OH in H 2 O ionic compounds are more soluble in polar solvents NaCl in H 2 O or NH 3 (l) 12.2

6. Factors Affecting Solubility – Temperature – Pressure Solubility is the amount of solute that will dissolve in a given amount of solvent at a given temperature or pressure.

7. Factors Affecting the Rate of Dissolution – Stirring – Temperature – Particle size/Surface area

8. A saturated solution contains the maximum amount of a solute that will dissolve in a given solvent at a specific temperature. An unsaturated solution contains less solute than the solvent has the capacity to dissolve at a specific temperature. A supersaturated solution contains more solute than is present in a saturated solution at a specific temperature. Sodium acetate crystals rapidly form when a seed crystal is added to a supersaturated solution of sodium acetate. 12.1

9. Solubility

10. Concentration Units The concentration of a solution is the amount of solute present in a given quantity of solvent or solution. Percent by Mass % by mass = x 100% mass of solute mass of solute + mass of solvent = x 100% mass of solute mass of solution 12.3 Mole Fraction (X) X A = moles of A sum of moles of all components

11. Concentration Units Continued M = moles of solute liters of solution Molarity (M) Molality (m) m = moles of solute mass of solvent (kg) 12.3

12. What is the molality of a 5.86 M ethanol (C 2 H 5 OH) solution whose density is 0.927 g/mL? m =m = moles of solute mass of solvent (kg) M = moles of solute liters of solution Assume 1 L of solution: 5.86 moles ethanol = 270 g ethanol 927 g of solution (1000 mL x 0.927 g/mL) mass of solvent = mass of solution – mass of solute = 927 g – 270 g = 657 g = 0.657 kg m =m = moles of solute mass of solvent (kg) = 5.86 moles C 2 H 5 OH 0.657 kg solvent = 8.92 m 12.3

13. Saturated, Unsaturated & Supersaturated Ex.1) If 10.0 g of KCl is dissolved in 100.0 g of water at 20.0 o C, then would the solution be described as unsaturated, saturated, or supersaturated? ________________________________________. Ex.2) If 10.0 g of KClO 3 is stirred into 100.0 g of water at 20.0 o C, then would the solution be described as unsaturated, saturated, or supersaturated? ________________________________________. Ex.3) If 10.0 g of KClO 3 is dissolved in 100.0 g of water at 20.0 o C, then would the solution be described as unsaturated, saturated, or supersaturated? ________________________________________. unsaturated saturated with about 1 g of undissolved KClO 3 supersaturated

14. Saturated, Unsaturated & Supersaturated Ex.4) If 100.0 g of KI is stirred into 100.0 g of water at 20.0 o C, then would the solution be described as unsaturated, saturated, or supersaturated? ______________________________________ Ex.5) If 100.0 g of KNO 3 is stirred into 100.0 g of water at 60.0 o C, then would the solution be described as unsaturated, saturated, or supersaturated? ______________________________________ Ex.6) How many grams of KNO 3 will exactly saturate 200.0 g of H 2 O at 20.0 o C? ______________ g unsaturated ≈70

15. Temperature and Solubility Solid solubility and temperature solubility increases with increasing temperature solubility decreases with increasing temperature 12.4

16. Temperature and Solubility O 2 gas solubility and temperature solubility usually decreases with increasing temperature 12.4

17. Watch the following video: http://www.youtube.com/watch?v=XSGvy2FPfCw http://www.youtube.com/watch?v=XSGvy2FPfCw What kind of a solution is it?

18. Need more help? http://www.wwnorton.com/college/chemistry/gil bert2/tutorials/interface.asp?chapter=chapter_0 4&folder=saturated_solutions http://www.wwnorton.com/college/chemistry/gil bert2/tutorials/interface.asp?chapter=chapter_0 4&folder=saturated_solutions – Norton tutorial on solubility http://www.youtube.com/watch?v=zjIVJh4JLNo& edufilter=d3ViuWqXvxQy1rRgssBz8Q http://www.youtube.com/watch?v=zjIVJh4JLNo& edufilter=d3ViuWqXvxQy1rRgssBz8Q – Basic solubility http://www.youtube.com/watch?v=4VltXjR64SU &edufilter=d3ViuWqXvxQy1rRgssBz8Q http://www.youtube.com/watch?v=4VltXjR64SU &edufilter=d3ViuWqXvxQy1rRgssBz8Q – Molarity vs. Molality