3. Water

Acids and Bases

Acids, Bases and pH

The Strongest Bases in the World

Acid-Base Reactions in Solution: Crash Course Chemistry #8

 any compound that accepts hydrogen ions 

 a material that resists changes in the pH of a solution 

 a compound that donates hydrogen ions to a solution 

How do we define an acid?

An acid is __________.

 lower the hydrogen ion concentration and lower the pH 

 No. A lower pH means a higher hydrogen ion concentration. 

 increase the hydrogen ion concentration and lower the pH 

 No. This describes the result of adding an acid. 

 increase the hydrogen ion concentration and increase the pH 

 No. A higher pH means a lower hydrogen ion concentration. 

 lower the hydrogen ion concentration and increase the pH 

It might help to think of a base as the opposite of an acid.

Adding a base tends to __________ of a solution.

H2O &rarr; H+ + OH&ndash;

 No. Although hydrogen ions are produced, hydroxyl ions are also produced in equal numbers. 

NaOH &rarr; Na+ + OH&ndash;

 No. In this reaction, no free hydrogen ion has been produced. 

NH3 + H+ &rarr; NH4+

 No. This reaction reduces the concentration of hydrogen ions. 

HF &rarr; H+ + F&ndash;

Consider the definition of acid.

Which of the following dissociations is that of an acid?

Animation: Acids, Bases, and pH

The strengths and weaknesses of acids and bases - George Zaidan and Charles Morton

According to data presented in this chapter, which of the following are correct? Select True or False for each statement.
T/F When individuals change in response to challenges from the environment, their altered traits are passed on to offspring.
T/F Species are created independently of each other and do not change over time.
T/F Populations—not individuals—change when natural selection occurs.
T/F The traits of populations become more perfect over time.

 increase the hydrogen ion concentration and raise the pH 

 No. As the hydrogen ion concentration increases, the pH decreases. 

 decrease the hydrogen ion concentration and raise the pH 

 No. Acids increase the hydrogen ion concentration; they do not lower it. Adding a base would produce the results indicated in this choice. 

 decrease the hydrogen ion concentration and lower the pH 

 No. Acids increase the hydrogen ion concentration. 

Consider the properties of acids.

Adding acid tends to __________ of a solution.

The buffering action of carbonic acid (H2CO3) causes the pH of seawater to rise.

More carbon dioxide causes an increase in carbonic acid (H2CO3), which leads to an increase in the concentration of carbonate ion (CO32&ndash;).

 No. The increase in carbon dioxide does cause an increase in carbonic acid. However, the increase in carbonic acid causes a decrease in the concentration of carbonate ion. 

There is no cause for concern. Carbonic acid (H2CO3) is an excellent buffer and will help keep the pH of seawater constant.

 No. When carbonic acid is present in equilibrium with bicarbonate ion, a buffer system exists. However, if carbonic acid is continually added to the system, the system is not in equilibrium. 

More carbon dioxide causes an increase in carbonic acid (H2CO3), which leads to a decrease in the concentration of carbonate ion (CO32&ndash;).

Apply the equation for the carbonic acid/bicarbonate buffer system to the seawater problem.

Why is the increasing amount of carbon dioxide being taken up by the oceans a cause for concern?

Both the release of H​+​ and an increase in pH.

Both the release of H+ and a decrease in pH.

The release of H+ into the solution only.

The addition of an acid like HCl to an aqueous solution (pure water) would result in:a) An increase in pH only.b) Both the release of H+ and an increase in pH.c) Both the release of H+ and a decrease in pH.d) The release of H+ into the solution only.e) A decrease in pH only.

Acids

 increases the oceanic concentration of carbonic acid 

No. This is true because when CO2 dissolves in seawater, it reacts with water to form carbonic acid, but there is another correct answer.

No. The absorption of CO2 increases the concentration of carbonic acid, which does increase the acidity and lower the pH of seawater. However, recall that an increase in acidity corresponds with a decrease in pH.

 reduces the carbonate ion concentration in the oceans and threatens calcifying organisms in marine ecosystems 

No. This is true because the absorption of CO2 by the oceans leads to a decrease in the carbonate ion concentration, which is required for calcification, the production of calcium carbonate (CaCO3) by many marine organisms, but there is another correct answer.

 increases the hydrogen ion concentration in the oceans but decreases the carbonate ion concentration and threatens the livability of the oceans for organisms that produce calcium carbonate shells 

Consider how certain solutes can affect the relative concentration of hydrogen and hydroxide ions in an aqueous solution.

The absorption of human-generated CO2 by the oceans __________.

The geneticist James Crow wrote that successful scientific theories have the following characteristics: (1) They explain otherwise puzzling observations; (2) they provide connections between otherwise disparate observations; (3) they make predictions that can be tested; and (4) they are heuristic, meaning that they open up new avenues of theory and experimentation. Crow added two other elements of scientific theories that he considered important on a personal, emotional level: (5) They should be elegant, in the sense of being simple and powerful; and (6) they should have an element of surprise. How well does the theory of evolution by natural selection fulfill these six criteria?

What Are Acids & Bases? | Chemistry Basics

a) NH4+ → NH3 + H+

b) H2CO3 → HCO3- + H+

c) NaOH → Na+ + OH-

d) HCl → H+ + Cl-

Which of the following reactions is most consistent with that of a base?a) NH4+ → NH3 + H+b) H2CO3 → HCO3- + H+c) NaOH → Na+ + OH-d) HCl → H+ + Cl-

The Strongest Acids in the World

Increasing the concentration of hydroxide ions.

Decreasing the concentration of hydrogen ions.

Decreasing the concentration of hydroxide ions.

Increasing the concentration of hydrogen ions.

In what way(s) do bases work to increase the pH of a solution?a) Increasing the concentration of hydroxide ions.b) Decreasing the concentration of hydrogen ions.c) Decreasing the concentration of hydroxide ions.d) Increasing the concentration of hydrogen ions.e) Both a &amp; b.f) Both c &amp; d.

Bases

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