BASESACIDS

· Compare and contrast acid and base properties. · Identify a substance as an acid or base · Identify acids and bases based on an indicator · Identify acids and bases based on their pH

Acid BaseIndicatorCorrosive

Key Words

ACID BASEBitter (soap) DO NOT taste.

Corrosive (burn)

Destroy Acids (neutralization)

Conduct electricity

Feel slippery(destroy proteins & fats)

Sour (lemons)

Corrosive (burn)

Destroy bases (neutralization)

Conduct electricity

React with most metals(hydrogen gas is made)

Acidic

HH HCl NO3 2SO4 HBr

Basic (alkaline)

OHOH OHNa Ca( )2 K NH 3

Most acids and bases are aqueous when used.

Most acids and bases are ionic compounds and include polyatomic ions.

Acids tend to have “H” in their formula.

Bases often have polyatomic “OH” (hydroxide) - Usually bonded to a 1A or 2A metal.

OHCa( )2HNO3

POLYATOMIC ION ACID OR BASE SO4

-2 (sulfate ion) sulfuric acid

NO3-1 (nitrate ion) nitric acid

CO3-2 (carbonate ion) carbonic acid

PO4-3 (phosphate ion) phosphoric acid

OH-1 (hydroxide ion) sodium hydroxide

OH-1 lithium hydroxide

When dissolved in water, acids and bases dissociate into two ions.

HNO3 (s) (aq) + NO3-

(aq)

H2CO3 (s) 2 (aq) + CO3-2

(aq)

H+

H+

split apart into ions

The hydrogen ion is responsible for the acid properties.

The hydroxide ion is responsible for the base properties.

KOH(s) K+ (aq) + (aq)

Ca(OH)2 (s) Ca+2 (aq) + 2

(aq)

OH-

OH-

Indicators

A substance that changes colour when added to an acid or base is called an indicator.

There are many different types of indicators available.

We often use paper containing the litmus dye as an indicator (red or blue litmus paper).

Phenolphthalein Bromothymol blue

Universal Indicator

Methyl Orange

Litmus RED

Litmus BLUE

Acids BasesIndicators

(feeno-thay-leen)

• Most acids contain hydrogen.

• Most bases contain hydroxide (OH-)

• Acids dissociate in water to make hydrogen ions.

• Bases dissociate in water to make hydroxide ions.

• Indicators are substances that change colour to show the presence of an acid or base.