Acids and Bases What comes to mind when someone says acid? What comes to mind when someone says base?

Is a substance an acid or a base? The pH Scale Is a substance an acid or a base?

ACIDS An acid is a compound that increases the number of hydrogen ions when dissolved in water (H+). An acid solution tastes sour. An acid can change the color of certain compounds.

What is an ion? An ion is an atom that has lost or gained an electron giving it a positive (+) or negative (-) charge.

USES OF ACIDS Citric acid and ascorbic acid (Vitamin C) are found in orange juice. Carbonic acid and phosphoric acid give a “bite” to soft drinks. Acids in your stomach aid in digestion. Sulfuric acid is the most widely used industrial acid in the world. It is used in making metals, paper, paints, and fertilizers.

BASES A base is any compound that increases the number of hydroxide ions (OH-) when mixed with water. A base solution tastes bitter. A base solution feels slippery. A base can change the color of certain compounds.

Uses of Bases Bases are used in soaps. (remember, bases are slippery) Bases are used to make paper, in oven cleaners, and to unclog drains. Ammonia is a base and is used in many household cleaners.

Detecting Acids and Bases We are going to use Vernier Probeware to detect acid and base concentrations.

HOW DO WE MEASURE pH?

NEUTRAL ACID BASE 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 The pH Scale

It's important to control the pH of a plant to ensure proper growth. The pH affects the availability of plant nutrients. A low pH can drain nutrients from the soil so they don't reach plant roots. Soil pH also controls the solubility (mixability) of nutrients and minerals that are needed for plants to grow. Solubility is important because fourteen of the seventeen plant nutrients that are necessary for plant growth are derived from soil solution. Although most plants thrive better in acidic soils, others prefer soils that are basic (alkaline). For optimum growing, most plants need a soil that has a pH range from 5.8 to 7.0.

Let’s see what you’ve learned! Professor Know-It-All wants to know what you’ve learned. Answer the following questions carefully.

Question #1 Lemon juice has a pH of 2.2. Is it an acid or a base?

Question #2 Detergents such as Tide have a pH of about 10. Is Tide an acid or a base?

Question #3 Seawater has a pH of 8.2. Is seawater an acid or a base?

Question #4 The inside of your mouth has a pH of 7. Is it an acid or a base?

Question #5 How do you think we came up with the term “acid rain”?

You’ve just completed Professor Know-It-All’s Quiz Let’s see how you did!