acids, bases, & their solutions the ph scale is a substance an acid or a base?

ACIDS, BASES, & THEIR

SOLUTIONS

The pH Scale

Is a substance an acid or a base?

ACIDS• a compound that increases the

number of hydrogen ions (H+) when dissolved in water

• 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 & ascorbic acid (Vitamin C) =

orange juice• Carbonic & 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’s used in making metals, paper, paints, and fertilizers.

BASES• any compound that increases the

number of hydroxide ions (OH-) when mixed with water

• tastes bitter• feel slippery• A base can change the color of certain

compounds

Uses of Bases• used in soaps (remember, bases

are slippery)• 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

• You can detect an acid or a base using an indicator.

• INDICATOR - A substance that changes color in the presence of an acid or a base.

INDICATORS• Litmus paper is an indicator

An acid turns blue litmus paper redA base turns red litmus paper blue

• Cabbage juice can be used as an indicator.• pH paper- turns a color & then match it to

the pH scale given.• pH meter- will give you a number for the

solution.

HOW DO WE MEASURE pH & WHAT IS pH?

pH= stands for powers of Hydrogen.

---It’s a measure of the hydronium ion

concentration in a solution.

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

ACID BASE

NEUTRAL

The pH Scale

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

ACID BASE

NEUTRAL

The pH Scale

Let’s see what you’ve learned!Mrs. Borras wants to

know what you’ve learned. Answer the following questions carefully.

DO NOT ANSWER OUT LOUD!!!!! Write it down.

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”?

Question #6• 409 cleaner

contains ammonia that has a pH of 12. What will 409 do to red litmus paper?

Question #7• A soft drink

has a pH of 3.2. What will it do to a piece of red litmus paper?

You’ve just completed Mrs.

Borras’ Quiz

Let’s see how you did!