Two Types Of Chemical Reactions Chapter 21

Acids Donate and Bases Accept Acid is any chemical that donates an H+. A base is any chemical that accepts an H+.

Acids Donate and Bases Accept H3O + - Hydronium ion (Acid) OH– -Hydroxide ion ( Base)

Salt is the Product of an Acid-Base Reaction Salt and water is the product of an acid- base reaction. Acid + Base  Salt + water The reaction between an acid and a base is called a neutralization reaction.

Neutralization Reaction

Some Acids and Bases Are Stronger Than Others. Strong acids and bases tend to generate more ions than weak acids or bases.

Acid, Base, or Neutral Neutral - Same amount of H+ and OH- Acid- More H+ than OH- Base- More OH- than H+

pH Scale The pH scale is used to describe the strength of an acid or a base. Over 7 is a base, under 7 is an acid, exactly 7 is neutral

Formula for pH pH = - log [H+]

Indicators – Acid or Base? Indicators will determine whether a solution is acidic or basic by changing a certain color. Indicator Acid Base Litmus paper Red Blue Phenolphthalein Clear Pink Cabbage juice red Green-yellow

Measuring the pH To measure the pH of a solution other tools must be used. pH meter- an electronic device to measure pH.

Measuring the pH Hydrion Paper- paper that turns a different color for every pH.

Rainwater is Acidic Rainwater is naturally acidic. Water in the atmosphere reacts with pollutants to produce acid.

Ocean water is Basic Oceans are naturally basic. The oceans contain bases which neutralize the acids immediately.

Effects on the Environment As human create more pollutants the environment is getting more acidic. This is dangerous to life on land as well as in the oceans.

Carbon Dioxide Levels by Year

Oxidation and Reduction Reaction Electron Oxidation Loss of electron Reduction Gain of electron

The Energy of Flowing Electrons Electrochemistry- is the study of the relationship between electrical energy and chemical change. Oxidation and Reduction reactions produce electric current.

Electrical Energy Chemical energy is transformed into electrical energy.

Batteries Batteries create electrical energy by Oxidation-Reduction reactions.

Oxygen is Responsible for Corrosion Corrosion is the process whereby metal rusts. Iron + Oxygen + Water  Rust

Oxygen is Responsible for Combustion Combustion is an oxidation- reduction reaction between an nonmetallic material and oxygen. Gas + oxygen  Carbon dioxide + water

Oxygen is Responsible for Combustion