21: Acids and Bases
- Page ID
- 53929
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- 21.1: Properties of Acids
- This page discusses the benefits of a clean coffee maker and the effective method of using a vinegar solution to remove lime deposits, emphasizing the need to follow up with water to maintain coffee flavor. It also explains the properties of acids, including their sour taste, effects on indicators, reactions with metals and bases, and the neutralization process that produces salts and water.
- 21.2: Properties of Bases
- This page discusses the discomfort from excess stomach acid due to overeating and how antacids, which contain bases like magnesium hydroxide or sodium hydrogen carbonate, can alleviate this issue. It explains the characteristics of bases, including their bitter taste, slippery texture, and reactions with acids to form salt and water. Additionally, it highlights common bases found in household products and emphasizes the importance of safety when handling chemicals.
- 21.3: Arrhenius Acids
- This page discusses the inhospitable conditions on Venus, marked by extreme heat and a toxic atmosphere, rendering it unfit for human exploration. It also explains the Arrhenius acids, defined by their ability to release hydrogen ions in water, highlighting examples like hydrochloric and acetic acids, and distinguishes between monoprotic and polyprotic acids based on their ionizable hydrogens.
- 21.4: Arrhenius Bases
- This page discusses sodium hydroxide, a caustic chemical useful for cleaning and food processing, which ionizes in water to produce hydroxide ions. It also mentions other bases such as potassium, magnesium, and calcium hydroxide, highlighting their properties and uses. Sodium hydroxide is highly soluble and can cause severe burns, while magnesium hydroxide, being less soluble, is commonly found in antacid products like milk of magnesia.
- 21.5: Brønsted-Lowry Acids and Bases
- This page discusses the evolution of acid-base theories, starting with the Arrhenius theory, which had limitations related to solvents and non-ionizing substances. The Brønsted-Lowry theory, introduced in 1923, defined acids as hydrogen ion donors and bases as hydrogen ion acceptors, broadening the scope to include compounds like ammonia. It highlights the role of anions and molecules with lone-pair electrons in proton acceptance, enhancing the understanding of acid-base reactions.
- 21.6: Brønsted-Lowry Acid-Base Reactions
- This page explores the dual nature of acid-base reactions through the lens of the Brønsted-Lowry theory, highlighting proton transfer. It explains amphoterism in water, detailing how it can function as both an acid and a base. The text outlines the formation of conjugate bases from acids and conjugate acids from bases, underscoring the importance of conjugate acid-base pairs with various illustrative reactions.
- 21.7: Lewis Acids and Bases
- This page explores the evolution of acid-base theory, detailing the shift from Arrhenius and Brønsted-Lowry definitions to the broader Lewis theory, which encompasses electron pair acceptance and donation. A Lewis acid accepts electron pairs, while a Lewis base donates them, enabling classifications of acid-base reactions without hydrogen ions, exemplified by ammonia and boron trifluoride. The text concludes with a table summarizing the definitions of the three theories.
- 21.8: Ion-Product of Water
- This page explains the self-ionization of water into hydronium and hydroxide ions, represented by the ion-product constant \(K_w\) at \(1.0 \times 10^{-14}\). It categorizes solutions as acidic or basic based on hydrogen or hydroxide ion concentrations. A calculation example with hydrochloric acid is provided to illustrate how ion concentrations are determined using \(K_w\). The content mainly focuses on properties and calculations concerning water ionization and related solutions.
- 21.9: The pH Scale
- This page discusses grapefruit juice's acidity, with a pH between 2.9 and 3.3 due to citric and malic acids, which can damage tooth enamel over time. It explains the pH scale developed by Søren Sørensen, where lower values indicate higher acidity, with neutral being at pH 7 and values above indicating basicity. The scale helps simplify the identification of acidity in different solutions.
- 21.10: Calculating pH of Acids and Bases
- This page discusses the maintenance of tropical fish tanks, emphasizing the importance of monitoring water pH because tap water is often too alkaline. It covers the need for regular testing and understanding pH through calculations of hydrogen ion concentration. Key concepts include the relationships between hydroxide and hydrogen ions, as well as the use of moles, molarity, and the ion product of water (Kw) to determine pH, highlighting the relevance of chemistry in aquarium care.
- 21.11: The pOH Concept
- This page discusses Soap Lake's historical significance as a healing destination due to its mineral-rich waters. It explains the concept of pOH and its relationship with pH (pH + pOH = 14) and provides an example calculation for determining hydroxide concentration from a given pH, illustrating an acidic solution at pH 4.42. Additionally, it summarizes the relationships among hydrogen ion concentration, pH, and pOH.
- 21.12: Strong and Weak Acids and Acid Ionization Constant \(\left( K_\text{a} \right)\)
- This page discusses the etching of glass using hydrofluoric acid and other compounds while protecting certain areas. It explains the difference between strong and weak acids based on their ionization in water and introduces the acid ionization constant (\(K_a\)), which indicates an acid's strength. A table compares the ionization constants of various acids, illustrating their relative strengths.
- 21.13: Strong and Weak Bases and Base Ionization Constant
- This page discusses the heat management systems of space shuttles, which use ammonia-filled coils to dissipate heat into space. It also covers concepts related to acids and bases, explaining the complete ionization of strong bases versus the partial ionization of weak bases, like ammonia.
- 21.14: Calculating Acid and Base Dissociation Constants
- This page discusses the development of the pH meter by Arnold Beckman for testing fruit acidity, his founding of Beckman Instruments, and his contributions to science education, including a major donation to the University of Illinois. It also explains how to calculate the acid dissociation constant \(K_a\) and the base dissociation constant \(K_b\) using pH measurements for formic acid and ethylamine through systematic ICE table calculations.
- 21.15: Calculating pH of Weak Acid and Base Solutions
- This page discusses the important role of bees in pollination despite the risk of harmful stings, particularly for allergic individuals. It suggests baking soda as a remedy for minor stings. Additionally, it explains how to calculate the pH of weak acids and bases using their \(K_a\) and \(K_b\) values, providing a specific example with nitrous acid and illustrating the use of an ICE table for simplification in calculations.
- 21.16: Neutralization Reaction and Net Ionic Equations for Neutralization Reactions
- This page discusses neutralization reactions between acids and bases in aqueous solutions, resulting in salt and water. It highlights the practical use of carbon dioxide to neutralize alkaline wastewater and outlines strong acid-strong base reactions that yield neutral solutions, including net ionic equations.
- 21.17: Titration Experiment
- This page discusses current biodiesel research that emphasizes the use of used vegetable oils, highlighting the necessity for acid content assessment prior to lye addition for biofuel production. It explains the titration method employed to measure free acid levels, involving neutralization reactions and indicators like phenolphthalein to indicate completion. The equivalence point is reached when acid and base moles are equal, indicated by a color change in the solution.
- 21.18: Titration Calculations
- This page describes the saponification number calculation for soap production through fat hydrolysis with sodium hydroxide. It covers titration calculations, focusing on the acid-base relationship at the equivalence point. An example outlining the titration of sulfuric acid with sodium hydroxide illustrates how to determine sulfuric acid's molarity using known base values. Molarity and neutralization principles are highlighted throughout the text.
- 21.19: Titration Curves
- This page discusses Rene Descartes' contribution to Cartesian geometry and its role in graphing concepts, particularly in titration curves that show pH changes during titrations. It explains that the pH at the equivalence point is 7 for strong acid-strong base titrations, while it varies for weak acid-strong base (above 7) and strong acid-weak base (below 7) titrations, highlighting the influence of acid-base strength on pH at the equivalence point.
- 21.20: Indicators
- This page explores the bluegrass song "Boil Them Cabbage Down" and its scientific relevance, particularly the ability of boiled cabbage to produce a pH indicator dye. It explains how acid-base indicators, like phenolphthalein, change colors with pH levels and emphasizes the importance of selecting the right indicator for titrations. Additionally, it highlights the utility of universal indicators for comprehensive pH assessments.
- 21.21: Hydrolysis of Salts - Equations
- This page explores the chemistry of baking, focusing on ingredients like baking powder that contribute to fluffiness through carbon dioxide. It discusses how the pH of salt solutions can vary based on the strength of the acids and bases involved, highlighting that salts from weak acids and strong bases yield basic solutions, while those from strong acids and weak bases yield acidic solutions. The concept of salt hydrolysis is essential for determining the resulting pH of these solutions.
- 21.22: Calculating pH of Salt Solutions
- This page discusses the importance of pH management in swimming pool water, recommending a target of 7.2. It explains how to adjust pH using chemicals like liquid HCl, sodium bisulfate, and sodium carbonate. The effects of salt solutions on pH are examined, highlighting that sodium fluoride generates a basic solution, while ammonium chloride results in an acidic one due to their respective ion behaviors in water.
- 21.23: Buffers
- This page discusses diabetes mellitus as a disorder affecting glucose metabolism due to impaired insulin, leading to fat breakdown and potential pH imbalance. It explains the role of buffers, which are weak acids or bases that mitigate pH changes, with examples like acetic acid/acetate and carbonic acid/hydrogen carbonate. Additionally, it covers buffer capacity, indicating how much acid or base can be added before causing significant pH alterations, demonstrated through various buffer reactions.