Textbook Question
Complete the table. (All solutions are at 25 °C.)
Ch.17 - Acids and Bases
Chapter 17, Problem 54e
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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Identify the components involved in the solution: CH₃NH₂ is a weak base and HCl is a strong acid.
Calculate the moles of CH₃NH₂ using the formula: moles = concentration (M) × volume (L).
Calculate the moles of HCl using the formula: moles = concentration (M) × volume (L).
Determine if the moles of HCl are less than, equal to, or greater than the moles of CH₃NH₂ to see if there is an excess of weak base or if the strong acid completely neutralizes the weak base.
Conclude whether a buffer is formed: A buffer is formed if there is a significant amount of weak base and its conjugate acid (formed from the reaction with the strong acid) present in the solution.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Buffer Solutions
A buffer solution is a system that resists changes in pH upon the addition of small amounts of acid or base. It typically consists of a weak acid and its conjugate base or a weak base and its conjugate acid. Buffers are crucial in maintaining stable pH levels in various chemical and biological processes.
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03:02
Buffer Solutions
Weak Bases and Their Conjugate Acids
In this scenario, CH3NH2 (methylamine) is a weak base, and when it reacts with HCl (a strong acid), it forms its conjugate acid, CH3NH3+. The presence of both the weak base and its conjugate acid is essential for the formation of a buffer solution, allowing the system to neutralize added acids or bases.
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01:46Conjugate Acid-Base Relationships
Stoichiometry of Acid-Base Reactions
Stoichiometry involves the calculation of reactants and products in chemical reactions. In this case, determining whether a buffer forms requires calculating the moles of CH3NH2 and HCl to see if they can coexist in a ratio that maintains the buffer capacity. Understanding the stoichiometric relationships helps predict the outcome of mixing these solutions.
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01:09Acid-Base Reaction
Related Practice
Textbook Question
Like all equilibrium constants, the value of Kw depends on temperature. At body temperature (37 °C), Kw = 2.4×10–14. What are the [H3O+] and pH of pure water at body temperature?
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Textbook Question
The value of Kw increases with increasing temperature. Is the autoionization of water endothermic or exothermic?
Textbook Question
Calculate the pH of each acid solution. Explain how the resulting pH values demonstrate that the pH of an acid solution should carry as many digits to the right of the decimal place as the number of significant figures in the concentration of the solution. [H3O+] = 0.044 M [H3O+] = 0.045 M [H3O+] = 0.046 M
Textbook Question
Determine the concentration of H3O+ to the correct number of significant figures in a solution with each pH. Describe how these calculations show the relationship between the number of digits to the right of the decimal place in pH and the number of significant figures in concentration. pH = 2.50 pH = 2.51 pH = 2.52
Textbook Question
For each strong acid solution, determine [H3O+], [OH–], and pH. a. 0.25 M HCl