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Ch.16 - Aqueous Equilibria: Acids & Bases
McMurry - Chemistry 8th Edition
McMurry8th EditionChemistryISBN: 9781292336145Not the one you use?Change textbook
Chapter 16, Problem 76e

Calculate the H3O+ concentration to the correct number of significant figures for solutions with the following pH values. (e) -1.0

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1
Understand that pH is defined as the negative logarithm (base 10) of the hydronium ion concentration: \( \text{pH} = -\log[\text{H}_3\text{O}^+] \).
To find the \([\text{H}_3\text{O}^+]\) concentration, rearrange the formula to solve for \([\text{H}_3\text{O}^+]\): \([\text{H}_3\text{O}^+] = 10^{-\text{pH}}\).
Substitute the given pH value into the equation: \([\text{H}_3\text{O}^+] = 10^{-(-1.0)}\).
Simplify the expression: \([\text{H}_3\text{O}^+] = 10^{1.0}\).
Calculate \(10^{1.0}\) to find the \([\text{H}_3\text{O}^+]\) concentration, ensuring the result is expressed with the correct number of significant figures.

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Key Concepts

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

pH Scale

The pH scale measures the acidity or basicity of a solution, ranging from 0 to 14. A pH of 7 is neutral, while values below 7 indicate acidity and values above 7 indicate basicity. The scale is logarithmic, meaning each whole number change represents a tenfold change in hydrogen ion concentration.
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Hydronium Ion Concentration

The concentration of hydronium ions (H3O+) in a solution is directly related to its pH. The formula to calculate H3O+ concentration from pH is [H3O+] = 10^(-pH). For negative pH values, such as -1.0, this results in a concentration greater than 1 M, indicating a highly acidic solution.
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Significant Figures

Significant figures are the digits in a number that contribute to its precision. When performing calculations, the result should reflect the precision of the least precise measurement. In the context of pH and H3O+ concentration, it is important to express the final answer with the correct number of significant figures based on the given pH value.
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