pH and Buffers Overview

Questions and Answers

What are the two types of components that release protons (H+) when dissolved in water?

organic and inorganic

What do dextrose and sodium chloride solutions provide for hydration?

electrolytes, calories, and water

What is the physiological pH range of a cell?

6.8 to 7.4

What is the negative logarithm of hydrogen ion concentration referred to as?

pH Signup and view all the answers

A very weak acid such as water can effectively neutralize small amounts of added acids or bases.

False Signup and view all the answers

What is the pH of a solution if [OH-] = 0.040 M?

12.60 Signup and view all the answers

What is the acid dissociation constant (Ka) for acetic acid?

1.74 x 10-5 M Signup and view all the answers

How do you calculate [H+] when given a pH of 4?

1 x 10^-4 M Signup and view all the answers

What occurs to blood pH during acidosis?

it decreases Signup and view all the answers

What is the purpose of buffers in biochemical systems?

to prevent damage from increased acid or alkali production Signup and view all the answers

Study Notes

pH and Buffers Overview

Protons (H+) are released when cellular components dissolve in water, including weak acids.
Weak acids exist in equilibrium with their conjugate bases, forming buffer systems that regulate H+ concentrations.
A cell generates H+ ions equivalent to 2 liters of HCl daily, which can significantly lower pH.
Physiological pH range for cells is between 6.8 and 7.4; deviation can threaten cellular function.
Water, a very weak acid, dissociates but has a low ion product constant (Kw), with [H+] and [OH-] both approximately 10^-7 M.

Importance of Buffers

Buffers maintain pH within physiological ranges by providing weak acids and their conjugate bases.
Common buffered solutions include dextrose and sodium chloride, which supply electrolytes, calories, and hydration.
Sodium and chloride ions are vital for regulating the body's acid-base balance.

pH Scale

pH is defined as the negative logarithm of hydrogen ion concentration.
Typical biological fluid concentrations are low (around 10^-7 M), represented as pH 7.
For example, blood plasma typically has a pH of 7.4 (0.00000004 M).

pOH Scale and Weak Electrolytes

Weak electrolytes partially dissociate in water; acetic acid (CH3COOH) is a prime example with a dissociation constant (Ka) of 1.74 x 10^-5 M.
Human body pH optimal range (6.8 to 7.4) is crucial for enzymatic and organ functions.
Imbalances in blood pH can lead to acidosis (low pH) or alkalosis (high pH), impacting overall health.

Sample Calculations

pOH can be calculated using the formula: pOH = -log[OH-]; for example, if [OH-] = 0.040 M, then pOH = 1.3979, leading to pH = 12.60.
Another example: For a solution with pOH = 10.0, pH can be calculated as pH = 4, which corresponds to [H+] = 10^-4 M or 0.0001 M.
Calculation for HCl concentration of 5.0 x 10^-4 M: pH = -log(5.0 x 10^-4).

Method for Calculations

Input methods for calculating pH and pOH involve using calculators with logarithmic functions.
Following clear steps for each calculation ensures accuracy and understanding of logarithmic relationships in pH and pOH dynamics.

Description

This quiz covers the fundamental concepts of pH and buffer systems, essential for maintaining cellular functions. It explores the equilibrium between weak acids and their conjugate bases and highlights the significance of buffers in physiological pH regulation. Understand the vital role of electrolytes and ion concentrations in acid-base balance.