Factors Affecting Solubility

Question 1

Three major factors

Answer 1

> molecular structure/polarity
pressure
temperature

Question 2

Molecular structure/polarity

Answer 2

> non-polar solutes (hydrophobic molecules) are soluble in non-polar solvent (i.e. Vit A in fats)

> polar solutes (hydrophilic molecules) are soluble in polar solvents (Vit C in water bectons their O-H bonds)

> also depends on how big the functional groups are***

Question 3

Micelles

Answer 3

> fatty acids that align themselves to maximize H+ bonds between hydrophilic heads and water, and maximize London dispersion forces between hydrophobic tails (a round circle)

Question 4

Pressure

Answer 4

> important for dissolving gaseous solutes

> decrease in pressure with an increase in volume for the gas, less collisions hitting the surface, entering solvent, and more exiting (i.e. Carbonated drinks)

> increase in pressure, increased number of collisions, increasing rate of gas dissolution in solution, increased [], new equilibrium is reached

Question 5

Partial pressure

Answer 5

> determines frequency of collisions between gas and a solution’s surface, [] of gas in a solution and the rate at which gas dissolves into a solution

> increase in partial pressure = more collisions, greater []

Question 6

Henry’s Law

Answer 6

> it relates gas pressure above a solution to [gas] dissolved in a solution

C = kH*P
C = [dissolved gas] (M)
kH = Henry's Law Constant (M*atm)
P = partial pressure (atm)
**C and P have to be of same gas species

Question 7

Temperature

Answer 7

> important for dissolving solids, liquids and gases

> most solids’ solubility in water increases with temperature, but a few decrease (such as Na2SO4 and Ce2(SO4)3)

> gases’ solubility in water decreases with increasing temperature