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Acids and Bases. pH Scale. Indicates the concentration of hydronium ions in a solution. Goes from 0 (acidic) to 14 (basic) 7 is considered neutral (water). Litmus Paper. Used to determine the pH of a solution. Red litmus paper= red in acid and neutrals, blue in base.
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pH Scale • Indicates the concentration of hydronium ions in a solution. • Goes from 0 (acidic) to 14 (basic) • 7 is considered neutral (water)
Litmus Paper • Used to determine the pH of a solution. • Red litmus paper= red in acid and neutrals, blue in base. • Blue litmus paper= red in acid, blue in a base or neutral.
Phenolphthalein • Another indicator • Turns bright pink in the presence of a base. • Remains colorless in the presence of an acid.
Acids • Form H+ ions in water • pH below 7 • Strong acids have a pH between 1-3.
Tastes sour • Reacts with active metals to form H gas and a metal compound – residue or corrosion.
Common Acids • Sulfuric acid (H2SO4) • Nitric acid (HNO3) • Hydrochloric acid (HCl)
Found in: • Aspirin • Vitamin C • Citrus Fruits (oranges, lemons, grapefruits) • Vinegar • Carbonated drinks
Strong Acids • HI • HBr • HCl • HNO3 • H2SO4 • HClO4
Bases • pH above 7 • Strong bases have a pH range of 11-14. • Bitter taste • Slippery to the touch • Dissolves fats and oils by forming soap (helps to “cut” grease)
Also known as alkalines • In water, bases form hydroxide (OH-) ions.
Common bases • Potassium hydroxide • Sodium Hydroxide
Found in • Drain cleaners • Antacids (Tums, Rolaids) • Deodorants • Ammonia • Soap
Strong Bases • Group 1 and Group II hydroxides.
Buffers • Solutions that contain ions that react with acids or bases to minimize their effects
Neutralization • A chemical reaction between an acid and a base that takes place in a water solution.
Salt • A compound formed when the negative ions from an acid combine with the positive ions of a base. • A salt is neutral HCl + NaHCO3 -----> NaCl + CO2 + H2O Acid + base ----- salt + water
Acid or base? Got Milk?
Identifying acids, bases, and salts • What do you notice about all acids? • Bases? • Salts?