Acids and Bases

Properties of Acids

What is an Acid? An acid is any substance that creates

Hydrogen Ions (H+) in water.

Acids share several characteristics…1. Acids taste sour

2. Acids react with metals

3. Acids react with carbonates

4. Acids turn blue litmus red

Properties of Acids

Sour Taste Items such as citrus

fruits are acidic in nature

They contain citric acid which gives them their sour taste

Properties of Acids

Acids react with metals Acids will “eat away” at metals such as

magnesium zinc, and iron. This property is described as being corrosive

Acids react with carbonates Carbonate ions (CO3

2-) have a negative charge and when acids react with them Carbon Dioxide gas is produced

An example would be the reaction of Hydrochloric Acid (HCl) with Limestone

Uses of Acids

Acids are used in a variety of ways every day: Many of the foods we eat contain acids Acids are often used in cleaning supplies Acids in your stomach allow you to digest food Lactic acid in your muscles causes fatigue Acids are used in lawn care products

Examples of Acids

Hydrochloric Acid – HClNitric Acid – HNO3

Sulfuric Acid – H2SO4

What do you notice about the first letter of each?

What does this tell you about the molecule?

Properties of Bases

What is a base? A base is any substance that produces

Hydroxide Ions ( OH-) in water

Bases share several characteristics:1. Bases have a bitter taste

2. Bases feel slippery

3. Bases turn red litmus blue

4. Bases do not react with metals or carbonates

Properties of Bases

Bases have a bitter taste Tonic water is a drink

that has a bitter taste due to the base quinine.

Properties of Bases

Bases have a slippery feel Items such as soap and

shampoo are bases

Uses of Bases

Bases are also useful to us everyday: Baking soda reacts with acids in baking to

create the carbon dioxide gas that causes bread to rise

Milk of Magnesia and Calcium Carbonate are used to neutralize stomach acids

Many cleaning supplies have bases in them Bases are used to help make mortar and

cement

Examples of Bases

Sodium Hydroxide – NaOH Potassium Hydroxide – KOH Calcium Hydroxide – Ca(OH)2

Magnesium Hydroxide -- Mg(OH)2

What do you notice about the ending of each base?

What does this tell you about each molecule?

Measuring the Strength of Acids and Bases

To measure the strength of Acids and Bases we use the pH scale which ranges from 0 – 14. The pH scale measure the concentration of

Hydrogen Ions in a solution When pH is low, the concentration of hydrogen

ions is high. The lower the pH the stronger the Acid The higher the pH the stronger the base A pH of 7 is considered neutral

The pH scale…

What happens when Acids and bases React with each other?

The reaction between an acid and a base is called a neutralization reaction The products of these reactions are a salt and water

A salt is any ionic compound formed by a neutralization reaction

Water comes from the combination of the hydrogen ions and the hydroxide ions

Although it is called a neutralization reaction, the resulting solution is not always neutral (pH of 7). It depends on the strength of the acid and the base that are combined.