In this video, we're going to begin our lesson on acids and bases. What you all need to know is that many biological processes are affected by the concentration of dissolved hydrogen ions, or H+ ions, in the aqueous solution. The concentration of dissolved hydrogen ions can be abbreviated by brackets with an H+ in the middle. Anytime you see brackets in science, it means "the concentration of." What this means is the concentration of hydrogen ions. Acids and bases are substances that directly affect the concentration of hydrogen ions. This is really important because it will strongly affect many biological processes that we'll talk about later in our course. But in our next lesson video, we're going to talk more about exactly how acids directly affect the hydrogen ion concentration. Later, in a different video, we'll discuss how bases directly affect the hydrogen ion concentration. I'll see you all in our next lesson video to talk about acids.
Acids and Bases - Online Tutor, Practice Problems & Exam Prep
Acids are substances that increase the concentration of hydrogen ions (H+) in a solution, while bases decrease this concentration. For example, hydrochloric acid (HCl) dissociates in water to release H+ ions, raising their concentration. Conversely, sodium hydroxide (NaOH) dissociates to produce hydroxide ions (OH-), which react with H+ ions to form water, thus lowering their concentration. Understanding the acid-base balance is crucial for many biological processes, influencing pH levels and overall homeostasis.
Acids and Bases
Video transcript
Acids
Video transcript
In this video, we're going to introduce acids. And so acids are really just any chemical that increases a solution's concentration of hydrogen ions or H+ ions. And once again, recall that the concentration of hydrogen ions can be abbreviated with just brackets like this H+ in the middle. Because anytime we see the brackets in science, we know it means the concentration 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 to water, we could see an example of an acid. So notice over here on the far left, we're showing you 4 different molecules of hydrochloric acid or HCl, 1, 2, 3, and 4. 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 a hydrochloric acid molecule to water, it will actually split up into 2 components. It will split up into a hydrogen ion, and it will split up into a chloride anion. And so the H+, and the Cl-, is 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 anions here, 3 of 4 of them for that matter since we have 4 HCl molecules, and we also have 4 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 more hydrogen ions in the solution than what we had before. And so, we can say that we have increased the 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.
Bases
Video transcript
So now that we've introduced acids in our last lesson video, in this video we're going to introduce bases. 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 solution's concentration of hydrogen ions. A classic example of a base is Sodium Hydroxide or NaOH.
If we take a look at our image down below at the addition of Sodium Hydroxide NaOH to water, then we'll be able to see an example of a base. Notice over here on the far left, we're showing you three molecules of Sodium Hydroxide or NaOH: 1, 2, and 3. 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 OH- ions. You can see that when we add these three sodium hydroxide molecules to water, the sodium hydroxide molecules are going to split into sodium ions and hydroxide ions.
You'll notice that even in some pure water over here there's going to be a little bit of hydrogen ions floating around, and so you can see that we start with three hydrogen ions. What's important to note is that each of these hydrogen ions that we see here will actually interact with the hydroxide ions. When the hydrogen ions interact with the hydroxide ions, it creates water molecules. You can see that the H+ ions are now being decreased.
Over here in the last beaker, because once again all of the OH- ions interact with the H+ ions, to form water molecules, notice that in this final beaker over here on the right, the concentration of hydrogen ions has indeed been decreased. Unlike acids, which result in increased hydrogen ion concentration, bases result in decreased hydrogen ion concentration just as we see here. This really 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?
NH4+ → NH3 + H+
H2CO3 → HCO3- + H+
NaOH → Na+ + OH-
HCl → H+ + Cl-
The addition of an acid like HCl to an aqueous solution (pure water) would result in:
An increase in pH only.
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.
A decrease in pH only.
In what way(s) do bases work to increase the pH of a solution?
Increasing the concentration of hydroxide ions.
Decreasing the concentration of hydrogen ions.
Decreasing the concentration of hydroxide ions.
Increasing the concentration of hydrogen ions.
Both a & b.
Both c & d.
Do you want more practice?
More setsYour Anatomy & Physiology tutors
- Consider the reaction between carbon dioxide and water to form carbonic acid: CO2(g)+H2O(l)⇌CH2O3(aq) In the...
- When H2 and CO2 react, acetic acid can be formed spontaneously while the production of formaldehyde requires a...
- Which of the following is not a property of water?a. Water has a high heat capacity.b. Water doesn't take heat...
- Mark the following statements as true or false. If a statement is false, correct it to make a true statement.a...
- Mark the following statements as true or false. If a statement is false, correct it to make a true statement.c...
- Mark the following statements as true or false. If a statement is false, correct it to make a true statement.d...
- A salt is:a. a metal cation bonded to a nonmetal anion.b. a hydrogen ion donor.c. an electrolyte that conducts...