Acids An acid is a substance that produces Hydrogen ion H + or hydronium H 3 O + in solution
Properties of Acids 1. taste sour 2. electrolytes – conduct electricity because of ions 3. corrosive – eat away at metals as metallic compounds and hydrogen gas is produced
Different Acids AcidFormulaWhere Found Hydrochloric (strong) HCl Stomach, cleaning supplies, “muriatic acid” Sulfuric (strong) H 2 SO 4 Car batteries, fertilizer Nitric (strong) HNO 3 Explosives, fertilizers Phosphoric H 3 PO 4 Detergents, fertilizers Carbonic H 2 CO 3 Soda (carbonated) Ascorbic H2C2H6O6H2C2H6O6 Vitamin C (fruits and vergetables Acetylsalicylic HOOC-C 6 H 4 -OOCCH 3 aspirin Acetic (weak) CH 3 COOH vinegar
The most widely used chemical in the world is sulfuric acid. It can cause severe burns because it is a dehydrating agent. This means that it takes all of the water out of materials, including skin.
STRONG ACIDS A Strong Acid completely ionizes (breaks apart) in water and releases a lot of H +. Example: sulfuric acid (battery acid)
Weak Acids A Weak acid only partially beaks down in water, so it doesn’t release much H +. Example: acetic acid (vinegar)
Bases A BASE is a substance that produces hydroxide ions OH - in solution. AKA=Alkine
Strong Bases A strong base completely dissociates (breaks apart) in solution and releases lots of OH -. Example: sodium hydroxide
Weak Base A weak base does not completely break apart in solution and does not release as much OH - Example: Aluminum hydroxide
pH Scale pH is the measure of H 3 O + in a solution pH is used to measure the strength of acids and bases. It ranges from 0 to 14. Substances with a pH lower than 7 are acidic Substances with a pH higher than 7 are basic Substances with a pH of 7 are neutral
Indicators Substances that change color in the presence of acids and bases Examples: 1. bromythymol blue turns yellow for acid and blue for base 2. phenylthalein turns clear for acid and pink for base
Neutralization If you want to NEUTRALIZE an acid or base, you add a BUFFER.
Buffers Buffers are ACIDS, BASES, or SALTS that are mixed with acids or bases to make their pH closer to 7. If you want to neutralize an acid, your buffer must be a BASE If you want to neutralize a base, your buffer must be an ACID Buffers in your body help keep your blood’s pH at 7.4. This is necessary because most of your food contains ACIDS
Titration Process that can be used to determine the concentration of an acid or base
Neutralization is a chemical reaction between an acid and a base H + from the acid combine with OH - from the base to form water Metals from the base combine with nonmetals from the acid to form a salt Example: HCl + NaOH NaCL + H 2 O
Salts Most SALTS are formed with a METAL and a NONMETAL other than OXYGEN. Some salts are formed with a METAL and a POLYATOMIC ION.
SaltFormulaUses Sodium chlorideNaClFood preparation Sodium bicarbonate NaHCO 3 Baking soda Calcium carbonate CaCO 3 Chalk Ammonium chloride NH 4 ClBatteries Sodium phosphate Na 2 PO 4 Detergents
Acid Rain Unpolluted rain typically has a pH value of 5.6 which is acidic, but not harmful Any rain that is below 5.6 is considered acid rain Acid Rain Can: 1.Dissolve marble in buildings and statues 2.Corrode metal (buildings, cars) 3.Kill plankton (then fish die)
Ways Acid Rain can Occur Burning coal releases sulfur – sulfur combines with water in the air – sulfuric acid forms Car exhaust releases nitrogen oxide – combines with water – nitric acid forms
Ways to Prevent Acid Rain “scrubbers on smokestacks” Nuclear power Cleaner fuel
Soaps Soaps are organic salts, this means that they contain carbon. Soaps are made by reacting fats or oils with sodium hydroxide or potassium hydroxide. Soaps made with NaOH are solids Soaps made with KOH are liquids Glycerin is another product of this reaction which is used in lotion
The process of making soap is called SAPONIFICATION
Detergents Detergents are similar to soaps, but fo not form soap scum which is a precipitate that forms when soap is used in hard water (lots of minerals) This is why most laundry products are detergents, not soaps
Esters An ESTER is an organic compound formed by the reaction of an organic acid with an alcohol Esters are responsible for the odors and flavors of flowers, fruits, and other foods. Esters are added to jello and candy to give the flavors of strawberry, banana, or apple. Organic acids are also used to make polyester fibers