Wednesday, January 25, 2012

Enthalpy Calculations (ΔH°f)

Key Concepts for Doing Enthalpy Calculations

  1. When a reaction is reversed, the magnitude of ΔH stays the same, but the sign changes.
  2. When the balanced equation for a reaction is mulitplied by an integer, the corresponding value of ΔH must be multiplied by that integer as well.
  3. The change in enthalpy for a reaction can be calculated from the enthalpies of formation of the reactants and the products
  4. Elements in their standard states are not included in the enthalpy calculations for the reaction since the enthalpy of an element in its standard state is zero.

ΔH° = Σ(ν × ΔHf°) (products) - Σ(ν × ΔHf°) (reactants)

-- ΔH = exothermic
+ ΔH = endothermic

Friday, January 20, 2012

OxPho & ETC along Inner Mitochondrial Membrane

File:Mitochondrial electron transport chain—Etc4.svg

Types of Leukocytes (WBCs)

File:Hematopoiesis simple.svg

1) Granular Leukocytes: Neutrophils, Basophils, Eosinophil, NK Cells...
- inflammation & allergic reactions
2) Lymphocytes: T & B Lymphocytes...
- immune response
3) Monocytes: Macrophages
- phagocytosis

Wednesday, January 18, 2012

Tuesday, January 17, 2012

Hund's Rule (Quantum Numbers)

namesymbolorbital meaningrange of valuesvalue example
principal quantum numbernshell1 ≤ nn = 1, 2, 3, …
azimuthal quantum number (angular momentum)subshell (s orbital is listed as 0, p orbital as 1 etc.)0 ≤ n − 1for n = 3:
= 0, 1, 2 (s, p, d)
magnetic quantum number, (projection of angular momentum)menergy shift (orientation of the subshell's shape)mfor = 2:
m = −2, −1, 0, 1, 2
spin projection quantum numbermsspin of the electron (−½ = counter-clockwise, ½ = clockwise)−½, ½for an electron, either: −½, ½

This model describes electrons using four quantum numbers, n, , m, ms. It is also the common nomenclature in the classical description of nuclear particle states (e.g. protons and neutrons).

  • The first, n, describes the electron shell, or energy level.
    • The value of n ranges from 1 to "n", where "n" is the shell containing the outermost electron of that atom. For example, in caesium (Cs), the outermost valence electron is in the shell with energy level 6, so an electron in caesium can have an n value from 1 to 6. This is known as the principal quantum number.
  • The second, , describes the subshell (0 = s orbital, 1 = p orbital, 2 = d orbital, 3 = f orbital, etc.).
    • The value of ranges from 0 to n − 1. This is because the first p orbital ( = 1) appears in the second electron shell (n = 2), the first d orbital ( = 2) appears in the third shell (n = 3), and so on. A quantum number beginning in 3, 0, … describes an electron in the s orbital of the third electron shell of an atom.
  • The third, m, describes the specific orbital (or "cloud") within that subshell.*
    • The values of m range from − to . The s subshell ( = 0) contains only one orbital, and therefore the m of an electron in an s subshell will always be 0. The p subshell ( = 1) contains three orbitals (in some systems, depicted as three "dumbbell-shaped" clouds), so the m of an electron in a p subshell will be −1, 0, or 1. The d subshell ( = 2) contains five orbitals, with m values of −2, −1, 0, 1, and 2.
  • The fourth, ms, describes the spin of the electron within that orbital.*
    • An electron can have a spin of ±½, ms will be either, corresponding with "spin" and "opposite spin." Each electron in any individual orbital must have different spins, therefore, an orbital never contains more than two electrons.

* Note that, since atoms and electrons are in a state of constant motion, there is no universal fixed value for m and ms values. Therefore, the m and ms values are defined somewhat arbitrarily. The only requirement is that the naming schematic used within a particular set of calculations or descriptions must be consistent (e.g. the orbital occupied by the first electron in a p subshell could be described as m= −1 or m = 0, or m = 1, but the m value of the other electron in that orbital must be the same, and the m assigned to electrons in other orbitals must be different).

Saturday, January 14, 2012

Bond Strength/Bond Length/Bond Order

Bond

# of electrons

Bond Order

Bond Strength

Bond Length

Single

2

1

Weakest

Longest

Double

4

2

Triple

6

3

Strongest

Shortest

Important points to remember about bond enthalpies:

  • Bond enthalpy is the energy required to break a bond
  • The stronger the bond, the higher the bond enthalpy
  • Bond enthalpy is always positive (endothermic)
  • Bond formation, EXOthermic, energy out
  • Bond breaking, ENDOthermic, energy in

Isomers

Anomers: alpha/beta

Alpha = OH group DOWN!
Beta = OH group UP!

Friday, January 13, 2012

Electrical Circuits

Sweet green-board chem guy: (Capacitors, Voltage/Current...)

Sunday, January 8, 2012

Electrical Conduction in Heart

1) SA Node, 2) AV Node, 3) Bundle of HIS, 4) Purkinje fibers

Tachycardias = fast / Bradycardia = slow




















Sites:

Heart Site: http://www.heartsite.com/html/electrical_activity.html
Wiki: http://en.wikipedia.org/wiki/Electrical_conduction_system_of_the_heart

Depolarization and the ECG


SA node: P wave (Atrial Systole, atrial repolarization)

AV node/Bundles: PR interval (Period of conduction)

Purkinje fibers/ventricular myocardium: QRS complex (Ventricular Systole, rapid ventricular depolarization)

Ventricular repolarization: T wave (Ventricular Diastole, ventricular repolarization)

ST Segment: The ventricles are repolarized

"also referred to as the isoelectric period, represents the period in which the entirety of both ventricles is depolarized. This roughly corresponds to the plateau phase of a ventricular action potential."

QT Segment: The time it takes for the DEpolarization AND REpolarization of the ventricles to occur

File:SinusRhythmLabels.svg

Videos:

EKG: http://www.youtube.com/watch?feature=player_detailpage&v=v3b-YhZmQu8