Podcast
Questions and Answers
What does the pH scale measure?
What does the pH scale measure?
concentration of hydrogen ions (H+)
In an acid-base equilibrium reaction, what does the Henderson-Hasselbalch equation relate pH to?
In an acid-base equilibrium reaction, what does the Henderson-Hasselbalch equation relate pH to?
A buffer solution is composed of a strong acid and a strong base.
A buffer solution is composed of a strong acid and a strong base.
False
Acid-base equilibria refers to the balance between the concentration of acids and bases in a ____.
Acid-base equilibria refers to the balance between the concentration of acids and bases in a ____.
Signup and view all the answers
What is the Henderson-Hasselbalch equation used to describe?
What is the Henderson-Hasselbalch equation used to describe?
Signup and view all the answers
What does the pH = pKa + log10([A-] / [HA]) equation represent?
What does the pH = pKa + log10([A-] / [HA]) equation represent?
Signup and view all the answers
When [A-] = [HA], what is the pH in relation to pKa?
When [A-] = [HA], what is the pH in relation to pKa?
Signup and view all the answers
If [A-] > [HA], how does the pH compare to pKa?
If [A-] > [HA], how does the pH compare to pKa?
Signup and view all the answers
If [A-] < [HA], how does the pH compare to pKa?
If [A-] < [HA], how does the pH compare to pKa?
Signup and view all the answers
In which fields or disciplines is the Henderson-Hasselbalch equation commonly applied?
In which fields or disciplines is the Henderson-Hasselbalch equation commonly applied?
Signup and view all the answers
Study Notes
Acid-base Equilibria
Definition
- Acid-base equilibria refers to the balance between the concentration of acids and bases in a solution
- Crucial in biological systems, as it affects the functioning of enzymes, proteins, and other biomolecules
pH Scale
- pH is a measure of the concentration of hydrogen ions (H+) in a solution
- pH = -log[H+]
- pH range: 0-14
- pH 7: neutral (neither acidic nor basic)
- pH < 7: acidic
- pH > 7: basic
Acid-Base Equilibrium Reactions
-
Acid dissociation:
- HA (acid) ⇌ H+ (proton) + A- (conjugate base)
- Example: CH3COOH (acetic acid) ⇌ H+ + CH3COO-
-
Base association:
- B (base) + H+ (proton) ⇌ BH+ (conjugate acid)
- Example: NH3 (ammonia) + H+ ⇌ NH4+
Henderson-Hasselbalch Equation
- Relates pH to the pKa of an acid and the concentrations of the acid and its conjugate base
- pH = pKa + log([A-]/[HA])
- pKa: negative logarithm of the acid dissociation constant (Ka)
Buffer Systems
- A buffer is a solution that resists changes in pH when an acid or base is added
- Composed of a weak acid and its conjugate base, or a weak base and its conjugate acid
- Buffering capacity: the ability of a buffer to resist pH changes
- Examples of buffer systems:
- Bicarbonate buffering system (H2CO3 + HCO3-)
- Phosphate buffering system (H2PO4- + HPO42-)
Importance of Buffer Systems
- Maintain a stable pH in biological systems
- Crucial for proper enzyme function and protein structure
- Help regulate the body's acid-base balance
Acid-base Equilibria
Definition
- Acid-base equilibria refers to the balance between the concentration of acids and bases in a solution
- Crucial in biological systems, as it affects the functioning of enzymes, proteins, and other biomolecules
pH Scale
- pH is a measure of the concentration of hydrogen ions (H+) in a solution
- pH = -log[H+]
- pH range: 0-14
- pH 7 is neutral, neither acidic nor basic
- pH < 7 is acidic
- pH > 7 is basic
Acid-Base Equilibrium Reactions
- Acid dissociation: HA ⇌ H+ + A-
- Example: CH3COOH (acetic acid) ⇌ H+ + CH3COO-
- Base association: B + H+ ⇌ BH+
- Example: NH3 (ammonia) + H+ ⇌ NH4+
Henderson-Hasselbalch Equation
- Relates pH to the pKa of an acid and the concentrations of the acid and its conjugate base
- pH = pKa + log([A-]/[HA])
- pKa is the negative logarithm of the acid dissociation constant (Ka)
Buffer Systems
- A buffer is a solution that resists changes in pH when an acid or base is added
- Composed of a weak acid and its conjugate base, or a weak base and its conjugate acid
- Buffering capacity is the ability of a buffer to resist pH changes
- Examples of buffer systems:
- Bicarbonate buffering system (H2CO3 + HCO3-)
- Phosphate buffering system (H2PO4- + HPO42-)
Importance of Buffer Systems
- Maintain a stable pH in biological systems
- Crucial for proper enzyme function and protein structure
- Help regulate the body's acid-base balance
Henderson-Hasselbalch Equation
- The Henderson-Hasselbalch equation describes the relationship between pH and pKa in a buffer system.
Equation
- pH = pKa + log10([A-] / [HA])
- The equation has four variables: pH, pKa, [A-], and [HA].
Variables
- pH: the negative logarithm of the hydrogen ion concentration
- pKa: the negative logarithm of the acid dissociation constant
- [A-]: the concentration of the conjugate base
- [HA]: the concentration of the acid
Key Concepts
- The pH of a buffer solution depends on the ratio of [A-] to [HA]
- When [A-] = [HA], the pH equals pKa, indicating the equivalence point
- If [A-] > [HA], the pH is greater than pKa, resulting in a basic solution
- If [A-] < [HA], the pH is less than pKa, resulting in an acidic solution
Applications
- The Henderson-Hasselbalch equation is used to calculate the pH of a buffer solution
- It helps determine the ratio of acid to conjugate base required for a specific pH
- Applications include biology, chemistry, and medicine, particularly in studying biological buffers and pH regulation
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your understanding of acid-base equilibria, including the pH scale, acidic and basic solutions, and its importance in biological systems.
