Acids and Bases Flashcards
True or false. There can be partial changes in polarity within 1 molecule?
True.
The __________ of adjacent water molecules allow them to form hydrogen bonds with one another.
Polar regions
Rate these bonds in order of strength.
Ionic bonds, covalent bonds, hydrogen bonds, Van der Waals
1.) Covalent (20-200 kcal/mol)
2.) Ionic (10-100 kcal/mol)
3.) Hydrogen (5 kcal/mol)
4.) Van der Waals (0.5 kcal/mol)
Solutes dissolve in __________.
Liquids.
_________ dissolve solutes.
Solvents
In a _________: solute dissolves in solvent.
Solution
Define solubility
Ease of dissolving
What does water dissociate into?
H+ + OH-
What is the pH range for cell survival?
6.8 - 7.8
Sulfuric acid is considered a (strong/weak) acid that (will/will not) ionize completely in water.
strong, will
An acid is a molecule that can give up a (H+/OH-).
H+
A base is a molecule that can give up a (H+/OH-).
OH-
HCl is an example of a (strong/weak) acid. When added to water it (completely/partially) ionizes.
strong/completely
An example of a (strong/weak) base is NaOH. When added to water it (completely/partially) ionizes.
strong/completely
An example of a (weak/strong) (acid/base) is CH3COOH. When added to water it will (completely/partially) ionize.
Weak/acid/partially
Acetic acid can act as a ______________ and its properties can be described by the ____________________ Equation.
Buffer/Henderson-Hasselbalch
The Henderson-Hasselbach equation only applies to (strong/weak) acids or bases.
Weak
What measurement is the acid dissociation constant?
pKa
What does pKa measure?
How strong or weak an acid is
True or false. pKa is a number that helps us understand how easily an acid can give away a hydrogen ion (H+) to become a negatively charged ion (anion).
True.
If an acid has a (low/high) pKa, it means it’s strong and readily gives away its hydrogen ion. If it has a (low/high) pKa, it’s a weak acid and doesn’t easily give away its hydrogen ion.
Low/high
Why are pKa values important?
They help us predict how substances will behave in chemical reactions and how they will interact with other chemicals. So, pKa is a way to quantify the strength of acids.
What does the Henderson-Hasselbach equation calculate (2)? And which values does it use to calculate this?
The pH of a solution given:
1.) The pKa (strength of acid/base) of a weak acid or base
2.) The concentration of the protonated or deprotonated forms
And the ratio of (deprotonated):(protonated) forms of a weak acid or base, given:
1.) The pH and the pKa of the weak
If you have a weak base B and it reacts with a proton (H+), it becomes its ________ because it has gained a proton.
conjugate acid BH+
Which equation is this:
pH=pKa + log (deprotonated)/protonated)
The Henderson-Hasselbach equation
If you have a weak acid HA and it loses a proton (H+), it becomes its ____________ because it has lost a proton.
Conjugate base A-
When the pH = pKa, the amount of _______and _______ are equal
Salt and acid
When pH = pKa what is the resulting pH?
4.74
Acedic acid will buffer best _______ pH units above and below its pKa.
1.0 pH units
Could acetic acid act as a buffer in the cell?
No. 4.74 +/- 1.0 is not in the range of 6.8-7.8 (cell pH)
Give an example of an extracellular fluid buffer system.
Bicarbonate-carbonic acid buffer system
Give an example of an RBC buffer system.
Hb buffer system
Give an example of an intracellular buffer system.
Phosphate buffer system
Proteins act as what 2 buffering systems?
Intracellular and plasma buffers
A _____________ can maintain a solution at roughly the same pH and resist the action of an alkaline or an acid. (Up to a point)
Buffer
HA represents a ___________ ________.
Weak acid.
H= H+
A= Whatever else is needed to complete the weak acid
In HA «» H+ + A- , what does A- represent?
Conjugate base
In HA «» H+ + A- Is the equilibrium equal
No, it pulls toward HA, because this is a weak acid. It only partially dissociates
When HA (weak acid) interacts with OH- (alkaline) what happens?
H20 and A- are produced, creating a neutral solution and a virtually unchanged pH.
When adding a soluble salt of HA to the solution, what happens? And why?
The soluble salt acts as a strong base and therefore can fully disassociate, creating a lot of A-, which will react with the H+ in the solution and create HA. Because this is a weak acid it will not have much effect on the pH.
How does a salt form in a neutralization reaction?
When a metal ion from a base replaces the H+ ion from an acid.
The direction of the reaction is determined by whether it raises or lowers the ______.
pH
In a buffering system, how is the pH lowered?
Releasing H+
In a buffering system, how is the pH raised?
Binding H+
How can we predict the chemical reaction based on the relative concentrations of H+.
If we are removing H+ from solution, we compensate by releasing H+ into solution.
If we are adding H+ to the solution, we compensate by removing H+ from the solution.
Which enzyme is working to create equilibrium with dissolved CO2 in the bicarbonate-carbonic acid buffering system?
Anhydrase
Which buffering system is the most effective extracellular buffer?
The bicarbonate buffering system
How can the lung modify its rate of CO2 removal?
By increasing ventilation
In CO2 formation in the tissues: When CO2 is produced as a result of fuel oxidation, it will dissolve and be converted to what, using what enzyme in the RBC.
Converted to H2CO3 by carbonic anhydrase.
In CO2 formation in the tissues: After CO2 is converted to H2CO3, what happens to it? Via what?
It will ionize and be exported in the plasma via the HCO3-/Cl- transporter (anion exchanger protein.)
HCO3- leaves the cell and Cl- enters.
How is the H+ buffered in the RBC, once H2CO3 is ionized?
It is buffered by Hb
What does the oxygenation of hemoglobin promote?
Dissociation of hydrogen ions from hemoglobin. The H+ then bind to the HCO3- (with carbonic anhydrase) and form carbonic acid, which then dissociates to form CO2 and H20, and the CO2 gets breathed out.
The body maintains it’s pH with buffers that help maintain neutral pH and by the expiration of ______ through the lungs, and the excretion of ______ and other ions through the kidneys.
CO2, NH4+
What 3 parts does a buffer have?
1.) Aqueous solution
2.) A weak acid
3.) The weak acid’s conjugate base
H20+HA «» H30+ + A-
If pH>pKa, then A- concentration is (> or <) than HA?
>
If pH is less than pKa, then A- concentration is (less than/greater than) HA?
Less than
