Presentation on theme: "Acids, Bases, and pH. Acids Release H + ions – so are called proton donors Contain H as the first element in the formula Taste sour Conduct electricity."— Presentation transcript:
Acids, Bases, and pH
Acids Release H + ions – so are called proton donors Contain H as the first element in the formula Taste sour Conduct electricity Corrosive – will steadily eat away at a substance Causes changes in an indicator
Bases Releases hydroxyl (OH) - ions – proton acceptor Contains (OH) - as the last set of elements Bitter taste, slippery feel Conducts electricity Corrosive Causes changes in an indicator
Indicators Changes color in the presence of certain substances Examples – pH paper – Litmus paper (red or blue) – Phenolphthalein
Litmus In an acid, litmus paper will appear pink, in a base, it will appear blue
pH Paper Has a variety of colors indicating specific pH ranges for the material. From dark red for acids to dark blue for bases.
Acid or Base Strength The more likely a compound is to release H + or (OH) - ions, the stronger it is. Even if a very strong acid or base (HCl or NaOH) is diluted with water, so it becomes less dangerous, it is still a strong substance.
Concentration The word concentration is a bit like the word crowded. High concentration Low concentration
Dilute vs Concentrate High concentration Low concentration Concentrate Dilute
pH Scale Measures concentration of H + ions. pH<7 - acidic pH>7 - basic pH = 7 - neutral
Title, Purpose, Materials, and Safety Title – Acid activity Purpose – To gain experience determining the pH of various substances using litmus paper and pH paper. Materials – ph Paper, Litmus Paper, forceps Safety – 1. Do NOT touch substances in beakers 2. You must wear goggles
Procedure 1.Gather Materials 2.You will be assigned to one station, using the forceps, dip a piece of red litmus paper into the substance at that station. Record color. 3.Repeat with blue litmus. 4.Switch stations when told. 5.One of the stations will involve pH paper, make sure you do not use the litmus paper at that station.
SubstanceRed Litmus ColorBlue Litmus ColorAcid or Base? Orange Juice NaCl + H 2 O Distilled H 2 O Vinegar Drano Sugar + H 2 O Aspirin + H 2 O Tea Lemon Juice Ammonia Baking Soda + H 2 O H2O2H2O2 Maalox