Effect of pH on Solubility

ex: CaCO3 in Oyster shells dissolves more strongly/easily in ACID...

http://www.youtube.com/watch?v=Lb8888u6chI

"But don't eat laxatives just to get calcium" hahaha

pH also affects its solubility – in an acidic solution, the equilibrium of the dissociation reaction of calcium fluoride is shifted more to the right as negative fluoride ions are removed, thus forcing the reaction in the direction of calcium fluoride dissolution. Note that pH does not affect the solubility of all salts. Typically, only weakly-soluble salts have pH-dependent solubilities. Examples include many hydroxides and carbonates.

http://www.mcatquestion.com/findquestion.php?arg1=1042

*Really interesting "Effects of pH on Solubility" BACTERIA/TEETH/CAVITIES/FLOURIDE example in Ebbing-Gammon (746)!!!

Ksp - Solubility equilibrium

Passage: The solubility of a solid compound such as a salt refers to the quantity of it that must be added to a particular volume of solvent to form a saturated solution. A solubility equilibrium results when a solid or gaseous compound is in chemical equilibrium with a solution of that compound. At equilibrium, the solution is saturated. The concept of solubility equilibrium is based on the assumption that when a solid dissolves in water or another solvent, it dissociates into the smaller, constituent units from which it was formed. Consider the salt calcium fluoride. When it dissociates, it produces three constituent atoms: one calcium atom (molar mass 40 grams/mol), and two fluorine atoms (each of molar mass 19 grams/mol).

Molar solubility is a term that refers to the maximum number of moles of solute that will dissolve in a liter of a solution before it becomes saturated. The molar solubility of calcium fluoride (CaF₂), for example, is 2.0 x 10^-4 moles per liter.

The solubility product constant (K_sp) is an important constant used to calculate molar solubility, and this constant refers to the product of the concentrations of ions in the equilibrium, each raised to the power of its coefficient in the equation.

Question 1: Calculate the K_sp of calcium fluoride.

(a) 1.6 x 10^-11
(b) 3.2 x 10^-11
(c) 4.8 x 10^-11
(d) 6.4 x 10^-11

Explanation: As stated in the text, the molar solubility of calcium fluoride is 2.0 x 10^-4moles per liter.

CaF₂ dissolves and dissociates as follows:

CaF₂ (s) ⇔ Ca²⁺ (aq) + 2 F^- (aq)
K_sp = [Ca²⁺] [F^-]²

The ratio between CaF₂ and Ca²⁺ is 1:1, but that between CaF₂ and F^- is 1:2. Consequently, dissolution of 2.0 x 10^-4 moles per liter of CaF₂ leads to production of 2.0 x 10^-4 moles per liter of Ca²⁺, but 4.0 x 10^-4 moles per liter of F^- in solution.

Insert the appropriate values into the K_sp equation:

K_sp = [Ca²⁺] [F^-]²
= (2.0 x 10^-4) (4.0 x 10^-4)²
= 3.2 x 10^-11

Oxidation Numbers, Oxidation-Reduction (Redox)

Determining Oxidation Numbers: http://www.youtube.com/watch?v=1ojEvef9oOw

Balancing Redox Reactions (ugggggh): http://chemistry.about.com/od/generalchemistry/ss/redoxbal_5.htm

Chem dude marry meeeeeeee:

1) http://www.youtube.com/watch?v=zcVLtoAdyd0&feature=related

2) http://www.youtube.com/watch?v=1ykHB_oGqw0

3) http://www.youtube.com/watch?v=STFiBTkj9RU&feature=related

WikiPremed: http://www.wikipremed.com/mcat_course.php?code=0214000200000000

***H2O is a reducing AND oxidizing agent!

Sarcomere

Dr. Martha Dixon: http://www.youtube.com/watch?v=-9DmO-SRY3E

Muscle Types

Smooth / Cardiac / Skeletal

Internal Energy (1st Law of Thermodynamics) & Sign Rules

http://www.wikipremed.com/01physicscards.php?card=565

q (+) = heat absorbed (energy is added to the system)

q (—) = heat evolved (energy is subtracted from the system)

W (+) = work done on the system (energy is added to the system)

W (—) = work done by the system (energy is subtracted from the system)

liter atmosphere (L·atm)

a unit of work or energy used in the study of confined gases. The behavior of gases is described, to a first approximation, by the ideal gas law PV = nRT. The ideal gas law is really an energy equation in which the left hand side, pressure P (in atmospheres) times volume V (in liters), measures the potential energy in the confined gas. 1 liter atmosphere is equal to approx. 100 joules...

******uggggghhhh case: W = P x dV = P (atm) x V (L) x (100J/l*atm)

Amino Acid TERMS

• The genetic code is composed of nucleotide triplets. In other words, three nucleotides in mRNA (a codon) specify one amino acid in a protein.
• The code is non-overlapping. This means that successive triplets are read in order. Each nucleotide is part of only one triplet codon.
• The genetic code is unambiguous. Each codon specifies a particular amino acid, and only one amino acid. In other words, the codon ACG codes for the amino acid threonine, and only threonine.
• The genetic code is degenerate (redundant!). In contrast, each amino acid can be specified by more than one codon.
• The code is nearly universal. Almost all organisms in nature (from bacteria to humans) use exactly the same genetic code. The rare exceptions include some changes in the code in mitochondria, and in a few protozoan species.