Chapter 16: Problem 61
Obtain the \(\mathrm{pH}\) corresponding to the following hydronium-ion concentrations. a. \(1.0 \times 10^{-8} M\) b. \(5.0 \times 10^{-12} M\) c. \(7.5 \times 10^{-3} M\) d. \(6.35 \times 10^{-9} M\)
Short Answer
Expert verified
a. pH = 8
b. pH ≈ 11.3
c. pH ≈ 2.1
d. pH ≈ 8.2
Step by step solution
01
Understanding the concept of pH
The pH of a solution is a measure of the hydrogen ion concentration. It is calculated using the formula: \( \mathrm{pH} = -\log_{10}(\mathrm{[H_3O^+]}) \), where \( \mathrm{[H_3O^+]} \) is the concentration of hydronium ions in moles per liter.
02
Calculate the pH for concentration a
For \( \mathrm{[H_3O^+]} = 1.0 \times 10^{-8} \ M \), the pH is calculated as follows: \[ \mathrm{pH} = -\log_{10}(1.0 \times 10^{-8}) = 8 \].
03
Calculate the pH for concentration b
For \( \mathrm{[H_3O^+]} = 5.0 \times 10^{-12} \ M \), the pH calculation is performed as: \[ \mathrm{pH} = -\log_{10}(5.0 \times 10^{-12}) \approx 11.3 \].
04
Calculate the pH for concentration c
For \( \mathrm{[H_3O^+]} = 7.5 \times 10^{-3} \ M \), the pH is computed with:\[ \mathrm{pH} = -\log_{10}(7.5 \times 10^{-3}) \approx 2.1 \].
05
Calculate the pH for concentration d
For \( \mathrm{[H_3O^+]} = 6.35 \times 10^{-9} \ M \), calculate the pH as follows: \[ \mathrm{pH} = -\log_{10}(6.35 \times 10^{-9}) \approx 8.2 \].
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Understanding Hydronium Ion Concentration
Hydronium ion concentration, denoted as \([H_3O^+]\), describes how many hydronium ions are present in a solution. This concentration is typically expressed in moles per liter (M), which tells us the amount of hydronium ions in a specific volume of solution. The concept of hydronium ions is central to understanding the acidity of a solution because they result from the combination of a hydrogen ion \(H^+\) with a water molecule (H2O).
The more hydronium ions present in a solution, the more acidic it is. Conversely, fewer hydronium ions suggest a less acidic, or more basic, solution. Hydronium ion concentration is crucial in calculating the pH of a solution, as it directly relates to the acidity or basicity of a given solution.
The more hydronium ions present in a solution, the more acidic it is. Conversely, fewer hydronium ions suggest a less acidic, or more basic, solution. Hydronium ion concentration is crucial in calculating the pH of a solution, as it directly relates to the acidity or basicity of a given solution.
The Role of Logarithmic Scale in pH
The pH scale is a logarithmic scale utilized to measure the acidity or basicity of a solution. Unlike a linear scale, where change is uniform, a logarithmic scale indicates units of tenfold differences. This means each whole-number shift in pH represents a tenfold change in the concentration of hydrogen ions.
The formula \( \text{pH} = -\log_{10}(\mathrm{[H_3O^+]}) \) uses this logarithmic understanding. By applying the negative logarithm to the hydronium ion concentration, we determine the pH, translating complex ion concentrations into the simple pH scale (ranging from 0 to 14).
The formula \( \text{pH} = -\log_{10}(\mathrm{[H_3O^+]}) \) uses this logarithmic understanding. By applying the negative logarithm to the hydronium ion concentration, we determine the pH, translating complex ion concentrations into the simple pH scale (ranging from 0 to 14).
- For instance, a pH of 3 is ten times more acidic than a pH of 4.
- This logarithmic nature allows large variations in ion concentration to be represented in a compact and comprehensible manner.
Basics of Acid-Base Chemistry
Acid-base chemistry revolves around the interaction of acids and bases and how they balance each other in a solution. Acids are substances that increase the concentration of hydrogen ions (or hydronium ions) in a solution, while bases decrease it by providing hydroxide ions (OH-) or by accepting hydrogen ions.
The concept of \( \text{pH} \) itself is a reflection of acid-base chemistry, as it quantifies the balance between these ions in a solution.
The concept of \( \text{pH} \) itself is a reflection of acid-base chemistry, as it quantifies the balance between these ions in a solution.
- A pH less than 7 indicates an acidic solution. This means the solution has a higher concentration of hydronium ions compared to pure water.
- A pH higher than 7 indicates a basic or alkaline solution, signifying more hydroxide ions present.
- A pH of 7 suggests a neutral solution, which is notably the pH of pure water at 25°C.