Final Exam Flashcards
What occurs on the surface when cold H2O cystals form?
CLONO2 (g) + H2O -> HOCl -> Hypochlorus acid + HNO3 (aq)
HCL -> H+ + CL-
Cl- react with newly formed hypochlorous to form:
Cl- + HOCl -> Cl2 + OH-
** CLONO2 + HCL -> CL2 + HNO3 **
What are two halogens that are very reactive?
Clorhine and bromine
What are the two resonance structures of ClONO2
What is the most electronegative element?
Fluorine
What occurs when you add CH3COO- from salt into acetic acid solution (CH3COO-)?
The system pushes the other way to the left and the Hydrogen goes down and the Ph goes up
How to buffers react to changes in pH?
They resist change in pH because they have both acidic and basic qualities.
How do you impact the pH of a solution?
By adjusting concentration of a the buffer.
What is the pH of a 0.12M lactic acid? What is the structure of the lactic acid?
The pH is 0.12 M Lactic Acid is 2.39
What is the pH of blood?
Slightly basic - 7.35-7.45
pH below 6.8 or above 7.8 you can die
If below 7.35 called acidocisi
If above 7.45 called alkalosis
What is the human bodies conjugate acid base pairing?
H2CO3 (Carbonic acid) + HCO3- (Bicarbonate)
What is the the conjugate base of citric acid?
(Tri)Sodium citrate (Na3C6H5O7)
H2COOH - Na+
H + COOH - Na+
H2COOH - Na+
What is a mechanism for the body to adjust equilibria?
CO2 - Removal of CO2 shifts the equilibria to the right
For a buffer to have a pH of 7.4, fairly removed from pk of H2CO3 (6.1 at 37 degrees)………..
The ratio of the acid base must be 20.
In normal blood HCO3- = 0.024 and H2CO3 = 0.0012M
The buffer has a high capacity to neturalzie additional acid but a low capactiy to neutrralize additional bases.
In the human body, what regulated the buffer system?
Lungs and Kidneys
What occurs if CO2 rises?
Equilibrium shifts to the left and H+ increases. Therefore, brain receptors trigger a reflex to breathe faster and deeper to get CO 2.
What do kidneys do to regulate pH?
Absorb or release H+ and HCO3-.
The pH of urine is in between 5.0 - 7.0
What occurs when O2 is low in the system?
When O2 is low, the equilibrium shifts to the left and CO2 is released.
An increase in H+ also decreases pH and shifts the equilibrium to the left.
What occurs during exercise for the body?
1) As O2 is consumed the equilibrium shifts to the left
2) Temperature increases equilibrium shifts to left
3) Lots of CO2 produced by metabolism. pH lowers and Eq shifts to the left
Calculate the sodium benzoate in a 0.20 M solution of benzoic acid to produce a pH of 4.0
To achieve a pH of 4.00, you need a sodium benzoate concentration of approximately 0.126 M in the buffer with 0.20 M benzoic acid.
What are two important characteristics of a buffer
- The amount of acid or base that can be neutralized before the pH begins to get out of control.
-> This depends on the amount of acid/base and also pH depends on Ka acid or Kb of base
When Hx is the same as X-, what is the result
The result will be pKa = pH.
This is better when a weak acid and conjugate bae are the same as they resist better to change,
We choose A buffer whose acid pKa is close to desired pHw
Let’s make a buffer of 0.300 mol acetic acid and 0.300 mol sodium acetate. Make this 1.0L with a pkA of 4.74. How does pH change if 0.020 omol of NaOH is added?
pH after adding 0.020 mol NaOH: 4.80
What is the pH of pure water?
7
What are indicators used for?
To signal the equivalence point of a titration
What is the equivalnce point?
The point at which stoichiometrically equivalent quantities of an acid and base are brought together.
The shape of titration curves help find equivalnce points.
What is infared spectrosocpy?
Vibration transitions correspond to distinct energy levels and differential functional groups can be detected.
What are the different functional groups of IR?
O-H, C=O, C-C, C-N
What is mass spectrometry?
Does not depend on taking in energy so you call it spectromety and not spectroscopy.
A molecule gets bombarded with high energy electrons. We can obtain molecular weight (molecular ion and grament ions) from breaking up the parent moleculy.
You are detecting mass/charge.
Good for large molecules like proteins
What is an MRI and what is it useful for?
Nuclear magnetic resonance, useful to detect atoms in nuclei: H, 13C, 15N, 31P - these are called NMR active and have a spin proton or neutron that have a magnetic moment.
