Acids, Bases, & Salts

Information about Acids, Bases, & Salts

Published on April 7, 2012

Author: WintersChemistry



Acids, Bases, & Salts: Acids, Bases, & Salts What is an ACID?: What is an ACID? pH less than 7 Neutralizes bases Forms H + ions in solution Corrosive-reacts with most metals to form hydrogen gas Good conductors of electricity Acids Generate Ions: Acids Generate Ions HNO 3 + H 2 O  H 3 O + + NO 3 Weak vs. Strong Acids: Weak vs. Strong Acids Weak Acids do not ionize completely: Acetic, Boric, Nitrous, Phosphoric, Sulfurous Strong Acids ionize completely: Hydrochloric, Nitric; Sulfuric, Hydriodic Common Acids : Common Acids HCl- hydrochloric- stomach acid H 2 SO 4 - sulfuric acid - car batteries HNO 3 – nitric acid - explosives HC 2 H 3 O 2 - acetic acid - vinegar H 2 CO 3 -carbonic acid – sodas H 3 PO 4 - phosphoric acid -flavorings What is a BASE? : What is a BASE? pH greater than 7 Feels slippery Dissolves fats and oils Usually forms OH - ions in solution Neutralizes acids Weak vs. Strong Bases: Weak vs. Strong Bases Weak Bases: ammonia; potassium carbonate, sodium carbonate Strong Bases: sodium hydroxide; sodium phosphate; barium hydroxide; calcium hydroxide Common Bases: Common Bases NaOH- sodium hydroxide (LYE) soaps, drain cleaner Mg (OH) 2 - magnesium hydroxide-antacids Al(OH) 3 -aluminum hydroxide-antacids, deodorants NH 4 OH-ammonium hydroxide- “ammonia” Types of Acids and Bases: Types of Acids and Bases In the 1800’s chemical concepts were based on the reactions of aqueous solutions. Svante Arrhenius developed a concept of acids and bases relevant to reactions in H 2 O. Arrhenius acid – produces hydrogen ions in water. Arrhenius base – produce hydroxide ions in water. PowerPoint Presentation: A broader ,more modern concept of acids and bases was developed later. Bronsted-Lowry acid- donates a hydrogen ion in a reaction. Bronsted – Lowry base – accepts a hydrogen in a reaction. PowerPoint Presentation: Conjugate acid- compound formed when an base gains a hydrogen ion. Conjugate base – compound formed when an acid loses a hydrogen ion. pH Scale: pH Scale PowerPoint Presentation: pH of Common Substances Timberlake, Chemistry 7 th Edition, page 335 Reactions with indicators: Reactions with indicators Indicator Acid color Neutral color Base color Phenolphthalein Colorless Faint pink Dark pink Bromthymol blue Yellow Green Blue Litmus Red ----- Blue pH paper: pH paper pH paper changes color to indicate a specific pH value. Buffers : Buffers A buffer is a solution that resists changes in pH when small amounts of acids and bases are added. Situations in which pH is controlled: Situations in which pH is controlled “Heartburn” Planting vegetables and flowers Fish Tanks and Ponds Blood Swimming pools Acids and Bases in Solution : Acids and Bases in Solution HCl + H 2 0  H 3 O + + Cl - (more hydronium ions, more acidic) NaOH in water  Na + + OH - (more hydroxide ions, more basic) NaOH + HCl  NaCl + HOH Acid + Base yields type of salt and water NH 3 + H 2 0  NH 4 + + OH - ammonia gas + water yields ammonium and hydroxide ions Acid Rain: Acid Rain Pollution in the air (sulfur dioxide, carbon dioxide, nitrogen dioxide) combines with water to form various acids. . PowerPoint Presentation: Rapid changes in pH can kill fish and other organisms in lakes and streams. Soil pH is affected and can kill plants and create sinkholes What is a SALT?: What is a SALT? A salt is a neutral substance produced from the reaction of an acid and a base. Composed of the negative ion of an acid and the positive ion of a base. One of the products of a Neutralization Reaction Examples: KCl, MgSO 4 , Na 3 PO 4 Neutralization Reaction : Neutralization Reaction A neutralization reaction is the reaction of an acid with a base to produce salt and water. Example H 2 SO4 + NaOH  NaHSO 4 + H 2 O Digestion and pH: Digestion and pH Digestion-process by which foods are broken down into simpler substances. Mechanical digestion-physical process in which food is torn apart (mouth) Chemical digestion- chemical reactions in which large molecules are broken down into smaller molecules. (stomach and small intestines) pH in the Digestive System: pH in the Digestive System Mouth-pH around 7. Saliva contains amylase, an enzyme which begins to break carbohydrates into sugars. Stomach- pH around 2. Proteins are broken down into amino acids by the enzyme pepsin. Small intestine-pH around 8. Most digestion ends. Small molecules move to bloodstream toward cells that use them PowerPoint Presentation: mouth esophagus stomach small intestine large intestine Digestive system Acids, Bases, and Salts The End : Acids, Bases, and Salts The End

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