Acids, Bases, and Salts

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Questions and Answers

Explain how the Brønsted-Lowry theory broadens the definition of acids and bases compared to the Arrhenius theory. Provide an example of a substance that is a base according to Brønsted-Lowry but not Arrhenius.

Brønsted-Lowry defines acids as proton donors and bases as proton acceptors, while Arrhenius defines acids as producing $H^+$ in water and bases as producing $OH^-$ in water. Ammonia ($NH_3$) is a base according to Brønsted-Lowry because it accepts protons, but it doesn't produce $OH^-$ ions in water, so it is not a base according to Arrhenius.

A solution has a pH of 3.0. If you dilute this solution by a factor of 100, what will be the approximate new pH, assuming ideal behavior?

The new pH will be approximately 5.0. Diluting an acidic solution decreases the concentration of $H^+$ ions. Each 10-fold dilution increases the pH by one unit.

Describe the chemical process of neutralization. What products are typically formed during this reaction, and how does it relate to changes in pH?

Neutralization is the reaction between an acid and a base, producing a salt and water. This process moves the pH of the solution towards neutral (pH 7) by reducing the concentration of excess $H^+$ or $OH^-$ ions.

How do strong acids and weak acids differ in terms of their dissociation in water, and what impact does this have on the concentration of hydrogen ions ($H^+$) in their solutions?

Strong acids completely dissociate into ions in water, resulting in a high concentration of $H^+$ ions. Weak acids only partially dissociate, resulting in a lower concentration of $H^+$ ions. Signup and view all the answers

Discuss the composition and mechanism of a buffer solution. How does it resist changes in pH when small amounts of acid or base are added?

A buffer solution consists of a weak acid and its conjugate base, or a weak base and its conjugate acid. It resists pH changes by neutralizing added acid or base. For example, the weak acid neutralizes added base, and conjugate base neutralizes added acid, thus maintaining a stable pH. Signup and view all the answers

Explain how the reaction between a strong acid and a strong base leads to the formation of a neutral salt. Provide an example with chemical formulas.

When a strong acid reacts with a strong base, the resulting salt is neutral because neither the cation nor the anion significantly affects the $H^+$ or $OH^-$ concentration in water. Example: $HCl + NaOH → NaCl + H_2O$. Signup and view all the answers

Describe two major environmental impacts of acid rain. How do these impacts affect ecosystems and man-made structures?

Acid rain acidifies lakes and streams, harming aquatic life, and damages forests by harming vegetation and soil. It also corrodes buildings and monuments made of stone or metal. Signup and view all the answers

Explain the role of sulfur dioxide ($SO_2$) and nitrogen oxides ($NO_x$) in the formation of acid rain. What are the primary sources of these pollutants?

$SO_2$ and $NO_x$ react with water in the atmosphere to form sulfuric and nitric acids, which contribute to acid rain. The primary sources of these pollutants are the burning of fossil fuels (coal, oil, and natural gas) and industrial processes. Signup and view all the answers

How can you experimentally determine if a salt formed from a neutralization reaction will produce an acidic, basic, or neutral solution when dissolved in water?

Dissolve the salt in water and measure the pH of the resulting solution. If the pH is less than 7, the salt is acidic; if it's greater than 7, the salt is basic; and if it's approximately 7, the salt is neutral. Signup and view all the answers

If a scientist adds a strong acid to a buffer solution, what chemical reaction occurs to minimize the change in pH? Use the example of an acetic acid/acetate buffer to illustrate.

In an acetic acid/acetate buffer, the acetate ion ($CH_3COO^−$) reacts with the added strong acid ($H^+$) to form acetic acid ($CH_3COOH$). This reaction consumes the added $H^+$ ions, preventing a significant drop in pH: $CH_3COO^- + H^+ \rightleftharpoons CH_3COOH$. Signup and view all the answers

Flashcards

Acids

Substances that donate protons (H+) or accept electrons.

Bases

Substances that accept protons (H+) or donate electrons.