Lesson 7 — Activity 2: Acids, Bases, and pH
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Lesson 7 — Activity 2:
Acids, Bases, and pH
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You saw in the previous activity that oxygen is a compound that has a role in several types of chemical reactions. Two more groups of chemical compounds that are involved in many common chemical reactions that you are already familiar with are acids and bases. In this activity, you will learn more about acids, bases, and the pH scale.
In L6:A3, you learned about acids and bases in common chemical compounds. In this activity, you will learn more acids and bases as well as where they sit on the pH scale.
Acids
You
might enjoy the sour taste of beverages like buttermilk, lemon juice,
and orange juice. Have you ever wondered what gives these beverages
their tangy taste? These liquids taste sour because they contain acids.
The word acid comes from the Latin word "acere," which means "sour." The
acids found in the liquids that we drink are natural acids.
Bases
Now, think about baking soda — the same white powder that you use to bake a cake. If you put baking soda in your mouth, you will spit it out immediately as it is bitter in taste. If you rub its solution between your fingers, it will feel soapy. Substances
like baking soda, which have a bitter taste and soap-like texture, are known as bases.
You
probably have examples of acids and bases in your cupboards and
garages. Some common acids are lemon juice, vinegar, milk, apples, carbonated drinks
(pop), toilet bowl cleaners, and the acid found in car batteries. Some
common bases (also known as alkalis) are baking soda, antacids such as Rolaids, drain cleaners,
soap, and ammonia.
In L6:A3, you learned about acids and bases in common chemical compounds. In this activity, you will learn more acids and bases as well as where they sit on the pH scale.
Acids
You
might enjoy the sour taste of beverages like buttermilk, lemon juice,
and orange juice. Have you ever wondered what gives these beverages
their tangy taste? These liquids taste sour because they contain acids.
The word acid comes from the Latin word "acere," which means "sour." The
acids found in the liquids that we drink are natural acids.
Bases
Now, think about baking soda — the same white powder that you use to bake a cake. If you put baking soda in your mouth, you will spit it out immediately as it is bitter in taste. If you rub its solution between your fingers, it will feel soapy. Substances like baking soda, which have a bitter taste and soap-like texture, are known as bases.
Now, think about baking soda — the same white powder that you use to bake a cake. If you put baking soda in your mouth, you will spit it out immediately as it is bitter in taste. If you rub its solution between your fingers, it will feel soapy. Substances like baking soda, which have a bitter taste and soap-like texture, are known as bases.
You
probably have examples of acids and bases in your cupboards and
garages. Some common acids are lemon juice, vinegar, milk, apples, carbonated drinks
(pop), toilet bowl cleaners, and the acid found in car batteries. Some
common bases (also known as alkalis) are baking soda, antacids such as Rolaids, drain cleaners,
soap, and ammonia.
The chemical properties of acids are the opposite of the chemical properties of bases. As a result, they react with each other and form water (H2O) and salt (not necessarily table salt, NaCl, but some form of a salty compound). This is called neutralization.
The physical properties of acids and bases can help us to identify them. Here are some of the properties acids and bases have when they are dissolved in water.
The pH scale
Whether
a liquid is an acid or a base depends on the type of ions in it. An ion
is a charged atom or molecule. It is charged because the number of
electrons do not equal the number of protons in the atom or molecule. If
a liquid has more hydrogen ions in it, then it is an acid, and if it
has more hydroxide ions in it, then it is a base. The term pH tells us
about the hydrogen ion concentration in a solution.
Whether a liquid is an acid or a base depends on the type of ions in it. An ion is a charged atom or molecule. It is charged because the number of electrons do not equal the number of protons in the atom or molecule. If a liquid has more hydrogen ions in it, then it is an acid, and if it has more hydroxide ions in it, then it is a base. The term pH tells us about the hydrogen ion concentration in a solution.
The pH
scale goes from 1 to 14. The liquids having a pH value between 0 to 7
are acids, with 0 being the strongest acid. The liquids having pH values
between 7 to 14 are bases, with 14 being the strongest base.
If a
liquid has a pH of 7, it is called neutral. The amount of hydrogen ions
and hydroxide ions in a solution are equal. Water has a pH of 7 because
when water breaks up, it splits into an equal amount of hydrogen and
hydroxide ions.
The pH scale goes from 1 to 14. The liquids having a pH value between 0 to 7 are acids, with 0 being the strongest acid. The liquids having pH values between 7 to 14 are bases, with 14 being the strongest base.
If a liquid has a pH of 7, it is called neutral. The amount of hydrogen ions and hydroxide ions in a solution are equal. Water has a pH of 7 because when water breaks up, it splits into an equal amount of hydrogen and hydroxide ions.
Click on the Play button below to watch a video that gives some examples of acids and bases (alkalis) on the pH scale.
Click on the Play button below to watch a video that gives some examples of acids and bases (alkalis) on the pH scale.
Digging Deeper
Click here to go to the Study Jams! website to watch a video. When you have finished watching the video, click on the "close" button in the upper right-hand corner to exit the video. Then, click on the "Test Yourself" button to see how much you know about acids and bases.
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