Post on 06-May-2015
description
Brainpop~Acids and Bases
Acid:
A substance that releases H+ ions in an aqueous solution
“aqueous” means: water
Characteristics of Acids:
Acids have a sour taste Acids react with metals
Acids contain Hydrogen
Many are poisonous and corrosive to skin
H
Strong Acids(break down completely to give off many H+ ions)
Weak Acids(only partially breaks down, gives less H+)
Mark Bishop Acid animation
Common Acids:
All others considered Weak (examples)
Strong Acids The Formula
Sulphuric acidHydrochloric acidHybrobromic acidHydroiodic acidNitric acidPerchloric acid
H2SO4
HClHBrHIHNO3
HClO4
Acetic acid (vinegar) HC2H3O2
Carbonic acid HCO3
Weak Acid The Formula
Base:
A substance that releases OH- ions in an aqueous solution
Characteristics of Bases:
Bases usually taste bitter Bases feel slippery Bases contain hydroxide ions STRONG bases are also poisonous and corrosive to skin
OH-
Strong Bases The Formulae
Lithium hydroxideSodium hydroxidePotassium hydroxideRubidium hydroxideCaesium hydroxideBarium hydroxideCalcium hydroxideStrontium hydroxide
LiOHNaOHKOHRbOHCsOHBa(OH)2
Ca(OH)2
Sr(OH)2
Common Bases:
(Hydroxides of Group 1 and Group 2 Metals are STRONG)
All others are WEAK
Some bases (VERY FEW) don’t have OH-
Most commonly: ammonia NH3
Reactions between acids and bases
When and acid and a base react with each other, the characteristic properties of both are destroyed. This is called neutralization.
Reactions between acids and bases
General formula for acid base reaction:
Acid + Base → H2O +Salt
“Salt” means any ionic compound formed from an acid/base reaction
NOT JUST NaCl !!
Neutralization Reaction Animation
Neutralization
HCl + NaOH → H2O + NaCl acid base water salt
NeutralizationAnother Example
HNO3 + KOH → H2O + KNO3
H OHKNO3
acid base water salt
IndicatorsAn indicator is a compound that will change color in the presence of an acid or base
Universal indicator (pH paper) Used for the full pH range
Red Litmus-Turns blue in baseBlue Litmus-Turns red in acid
Phenolphthalein-Turns pink in base
pHpH stands for “potential hydrogen” and is a measure of how many H+ ions there are in solution.
The MORE H+ there are, the LOWER the pH will be.
pH ScaleShows the range of H+
concentrations
High H+ concentration Low H+ concentration