Acids and Bases

in this video, we're going to begin our lesson on acids and bases. And so what you all need to know is that many biological processes are actually strongly affected by the concentration of dissolved hydrogen ions, or H plus ions, in the aqueous solution. And so the concentration of dissolved hydrogen ions can really just be abbreviated by brackets with an H plus in the middle. And so any time you see brackets in science, it means the concentration of and so what this brackets means is the concentration of hydrogen ions, and so acids and bases are substances that directly affect the concentration of hydrogen ions. And once again, the concentration of hydrogen ions is really, really important, because that will strongly affect many biological processes that will talk about later in our course. But in our next lesson video, we're going to talk more details about exactly how acids directly affect the hydrogen ion concentration. And then later in a different video, we'll talk about how bases directly affect the hydrogen ion concentration. And so I'll see you all in our next lesson. Video to talk about acids

in this video, we're going to introduce acids. And so acids are really just any chemical that increases a solutions concentration of hydrogen ions, or H plus ions, and once again recall that the concentration of hydrogen ions can be abbreviated with just brackets like this and it h plus in the middle. Because any time we see the brackets and science, we know it means the concentration of of what's in between the brackets. So this is the concentration of hydrogen ions here, so acids will increase the concentration of hydrogen ions in solution. And so, if we take a look at our example down below, at the addition of hydrochloric acid or HCL toe water, we could see an example of an acid. So notice over here on the far left, we're showing you four different molecules of hydrochloric acid or HCL 123 and four. And as its name implies, hydrochloric acid is an acid, which means that when we add it to water, it is going to increase the concentration of hydrogen ions. And so what happens when we add ah, hydrochloric acid molecule to water, it will actually split up into two components. It will split up into a hydrogen ion and it will split split up into a chloride an ion. And so the H plus on the C l minus eyes what each HCL molecule will split up into when we add it into pure water. And so notice over here in this beaker, we have these chloride and ions here, three of four of them, for that matter, since we have four HCL molecules and we also have four hydrogen ions. And so ultimately, what we can see is that through the addition of HCL to pure water at the end, we have an increase in the concentration of hydrogen ions. We have mawr hydrogen ions in the solution than what we had before. And so we can say that we have increased hydrogen ion concentration and really, that is it for acids. Acids are any substance that will increase the concentration of hydrogen ion. And once again, the concentration of hydrogen ion is really, really important when it comes to biological processes. And we'll get to learn more about that as we move forward in our course. But in our next video, we're gonna talk about bases, so I'll see you all there

So now that we've introduced acids in our last lesson video in this video, we're going to introduce bases. And so bases are pretty much the complete opposite of acids. And that's because instead of increasing the concentration of hydrogen ions, bases are any chemical that decreases a solutions concentration of hydrogen ions. Now a classic example of a base is sodium hydroxide or n a O. H. And so if we take a look at our image down below at the addition of sodium hydroxide or any H two water, then we'll be able to see an example of a base. And so notice over here on the far left, we're showing you three molecules of sodium hydroxide or N a O. H. 12 and three. And so when each of these sodium hydroxide molecules is added to water, they will actually split into two substances. They will split into sodium ions and hydroxide ions or O H minus ions. And so you can see that when we add these three sodium hydroxide molecules to water that the sodium hydroxide molecules are going to split into sodium ions and hydroxide ions. And so you'll notice that even in some pure water over here that there's going to be a little bit of hydrogen ions floating around, and so you could see that we start with three hydrogen ions. And so what's important to note is that each of these hydrogen ions that we see here will actually interact with the hydroxide ions. And so when the hydrogen ions interact with the hydroxide ions, it creates water molecules, and so you can see that the H plus ions are now being decreased. And so over here in the last beaker. Because once again, all of the O H minus ions interact with the H plus ions. Uh, toe form water molecules Noticed that in this final beaker over here on the right that the concentration of hydrogen ions has indeed been decreased. And so, unlike acids, which result in increased hydrogen ion concentration bases, we know result in decreased hydrogen ion concentration, just as we see here. And so really, this concludes our introduction to bases and we'll be able to get some practice as we move forward in our course. So I'll see you all in our next video

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^-

• A. a) NH₄⁺ → NH₃ + H⁺
• B. b) H₂CO₃ → HCO₃^- + H⁺
• C. c) NaOH → Na⁺ + OH^-
• D. d) HCl → H⁺ + Cl^-

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.

• 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.

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 & b.

f) Both c & d.

• 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 & b.
• F. Both c & d.