If the volume of blood in a normal adult is 5.0 L, what mass of HCl can be neutralized by the buffering system in blood before the pH falls below 7.0 (which would result in death)?

Name: Chemistry: A Molecular Approach
Author: Tro
ISBN: 9780134112831

Verified step by step guidance

Identify the buffering system in blood, which is primarily the bicarbonate buffer system: \( \text{HCO}_3^- + \text{H}^+ \rightleftharpoons \text{H}_2\text{CO}_3 \).

Determine the concentration of bicarbonate ions (\( \text{HCO}_3^- \)) in blood, which is typically around 24 mM.

Calculate the total moles of \( \text{HCO}_3^- \) in 5.0 L of blood using the formula: \( \text{moles} = \text{concentration} \times \text{volume} \).

Use the stoichiometry of the reaction to find the moles of \( \text{HCl} \) that can be neutralized, noting that 1 mole of \( \text{HCO}_3^- \) neutralizes 1 mole of \( \text{HCl} \).

Convert the moles of \( \text{HCl} \) to mass using the molar mass of \( \text{HCl} \) (36.46 g/mol) with the formula: \( \text{mass} = \text{moles} \times \text{molar mass} \).

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Buffering System

A buffering system in biological fluids, such as blood, helps maintain a stable pH by neutralizing acids and bases. In blood, bicarbonate (HCO3-) and carbonic acid (H2CO3) are key components that resist changes in pH, allowing the body to function optimally despite metabolic processes that produce acids.

pH Scale

The pH scale measures the acidity or basicity of a solution, ranging from 0 (very acidic) to 14 (very basic), with 7 being neutral. In biological systems, a pH below 7.0 indicates acidosis, which can be life-threatening. Understanding how pH changes in response to acid addition is crucial for determining the buffering capacity of blood.

Neutralization Reaction

A neutralization reaction occurs when an acid reacts with a base to produce water and a salt, effectively reducing the acidity of the solution. In this context, the hydrochloric acid (HCl) introduced into the blood will react with the bicarbonate ions in the buffering system, and calculating the mass of HCl that can be neutralized involves stoichiometry and the concentrations of the reactants.

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Textbook Question

The fluids within cells are buffered by H₂PO₄^- and HPO₄^2- . b. Could a buffer system employing H₃PO₄ as the weak acid and H₂PO₄^- as the weak base be used as a buffer system within cells? Explain.

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Textbook Question

Blood is buffered by carbonic acid and the bicarbonate ion. Normal blood plasma is 0.024 M in HCO₃^- and 0.0012 M H₂CO₃ (pK_a1 for H₂CO₃ at body temperature is 6.1).

c. Given the volume from part (b), what mass of NaOH can be neutralized before the pH rises above 7.8?

Textbook Question

Determine whether or not the mixing of each pair of solutions results in a buffer. c. 165.0 mL of 0.10 M HF; 135.0 mL of 0.050 M KOH

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Textbook Question

Determine whether or not the mixing of each pair of solutions results in a buffer. e. 105.0 mL of 0.15 M CH₃NH₂; 95.0 mL of 0.10 M HCl

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Textbook Question

Blood is buffered by carbonic acid and the bicarbonate ion. Normal blood plasma is 0.024 M in HCO₃^- and 0.0012 M H₂CO₃ (pK_a1 for H₂CO₃ at body temperature is 6.1).

a. What is the pH of blood plasma?