The document discusses solubility and dissolution rates. It defines solubility as the ability of a substance to dissolve in another, and discusses how "like dissolves like" with polar substances dissolving in polar solvents and nonpolar in nonpolar. It also discusses how to increase dissolution rates, such as by increasing temperature, surface area, or movement. For gases, dissolution is increased at lower temperatures and higher pressures. Concentration of solutions is also covered, defining unsaturated, saturated, and supersaturated solutions based on how close they are to the maximum solubility for a given temperature.

1. III. Rate of dissolving & Solubility A. Solubility is the ability of one thing to dissolve in another 1. miscible – able to dissolve 2. immiscible – unable to dissolve

2. 3. “like dissolves like” so polar substances dissolve in other polar substances but not in nonpolar stuff a. salt (ionic & polar) dissolves in water (polar) b. vitamin k (nonpolar) dissolves in fat (nonpolar) c. oil (nonpolar) does not dissolve in water (polar)

3. Vitamins Multi Vitamin Provides many essential vitamins “ Expensive urine” because most is urinated out! Water Soluble – will dissolve in water Vitamin C CAN’T be stored - must be replenished regularly Fat Soluble – will NOT dissolve in water (will only dissolve in oils) Can overdose Vitamin A, K … Can be ingested periodically, stored in body fat

4. B. Common ways to increase the rate of dissolving 1. Increase Temperature. Increasing the temperature adds more energy and creates more collisions of solute and solvent to help dissolve . a. Ex: dissolving sugar in Warm tea vs. cold tea

5. 2. Increase surface area. Smaller pieces dissolve more quickly because there are more places to interact between solvent and solute. Pulverize = crush or smash a. Ex: Sugar packets vs. Sugar cubes

6. 3. Increase movement (stirring). By adding motion you add kinetic energy and move the solvent around to dissolve it. a. Ex: Stirring the sugar into the tea vs. letting it dissolve on its own

7. C. Dissolving gases follow different rules 1. Gases dissolved in liquids prefer lower temperatures. Cold soda has more carbonation than warm sodas

8. 2. Prefer less movement, more movement lets the gas escape more easily. Shaken sodas lose the dissolved gases quickly & so have fewer bubbles.

9. 3. Increased Pressure increases rate of dissolving. So when the bottle the soda they bottle it under higher pressure to keep the gas dissolved in it

10. Solubility Solids are more soluble at... high temperatures. Gases are more soluble at... low temperatures & high pressures EX : nitrogen narcosis, the “bends,” soda

11. IV. Concentrations of solution – how “strong” or “weak” the solution is A. 3 types of solutions based on concentration of dissolved solute

12. 1. Unsaturated solution – Solution that can easily dissolve more of the solute does not require an increase in temperature to add more solute. a. Ex. Weak sweet tea or unconcentrated acid.

13. 2. Saturated solution – Solution that has the maximum amount of solute dissolved for that temperature. Any change in temperature will affect the concentration.

14. 3. Supersaturated solution – Solution that has a higher concentration of solute than it normally would at that temperature. It was heated up, come out of solution. Typically can’t be disturbed or it will crystallize.

15. Solubility increasing concentration SATURATED SOLUTION no more solute dissolves UNSATURATED SOLUTION more solute dissolves SUPERSATURATED SOLUTION becomes unstable, crystals form

16. B. Solubility Chart 1. Shows how the solubility changes at different temps

17. Solubility Table LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World , 1996, page 517 0 10 20 30 40 50 60 70 80 90 100 Solubility vs. Temperature for Solids Solubility (grams of solute/100 g H 2 O) KI KCl 20 10 30 40 50 60 70 80 90 110 120 130 140 100 NaNO 3 KNO 3 HCl NH 4 Cl NH 3 NaCl KClO 3 SO 2 shows the dependence of solubility on temperature gases solids

18. Solubility Solubility maximum grams of solute that will dissolve in 100 g of solvent at a given temperature varies with temp based on a saturated solution

19. Classify as unsaturated, saturated, or supersaturated per 100 g H 2 O 80 g NaNO 3 @ 30 o C unsaturated saturated unsaturated supersaturated 45 g KCl @ 60 o C 50 g NH 3 @ 10 o C 70 g NH 4 Cl @ 70 o C