ACIDS, BASES AND SALTS Objectives 2.1 To identify the properties normally used to classify substances in aqueous solutions as either acids, bases, or salts. 2.2 To determine the conditions under which substances will show the properties of acids, bases, or salts.
ACIDS Acids ACIDSThe word acids comes fromone of its characteristicproperties, its taste. ACIDS = “acidus” (latin word) meaning sour.
BASES Bases BASESBases are substances that arevery slippery to touch and have a strong bitter taste.
SALTS Salts SALTS Salts are a source of ions that are easily absorbed by living organisms. They are often used to change the physicalproperties of various solutions by lowering the freezing points or raising the boiling points
Properties of Acids, Bases and Salts Electrical Magnesium Taste/ Litmus Conductivity Touch PaperACID YES Reaction Sour Turns red Bitter/BASE YES No Reaction Slippery Turns Blue DependsSALT YES No Reaction Salty on the solution Electrolytes – solutions that conduct electricity
(USED TO DETECT ACIDS OR BASES) Litmus paper is a type of indicator (thin strip of paper that is dipped into a solution) 2 Types: Blue Litmus Paper Red Litmus PaperACIDS – Turn blue litmus paper redBASES – Turn red litmus paper blue BB
IndicatorsSALTS– not all salts are neutral- can be either acidic or basic (test with litmus paper)
Indicators Phenolphthalein is another type of indicator Bases turn clear phenolphthalein pink
“Making a solution chemically neutral” Chemically neutral – means does not contain an acid or base Neutralize it with a base Neutralize it with an acidAcids and bases neutralize each other forming a salt and water Ex. Acid + Base = Salt + water
Acids, bases and salts conduct electricity Tap water Distilled water -will conduct Tap water -does not Distilled water-(free-will conduct ions around) -conductnot -does -(free ions around) -(no free ions!) -conduct -(no free ions!)
o Review chart: (very important!) Electrical Magnesium Taste/ Litmus Conductivity Touch Paper YES Reaction Sour Turns ACID red Bitter/ YES No Reaction Slippery Turns BASE Blue Depends YES No Reaction Salty on the SALT solution