Warm-up• Name the following:

• LiBr – lithium bromide

• Be(NO3)2

– beryllium nitrate

• NO – nitrogen monoxide

Warm-up• List the four factors that affect reaction rates?• Temperature

– High temperature – fast reaction– Low temperature – slow reaction

• Surface area– Large surface area – fast reaction– Small surface area – slow reaction

• Stirring– Fast stirring – fast reaction– Slow stirring – slow reaction

• Concentration– High concentration – fast reaction– Low concentration – slow reaction

5-9: Acids & Bases

• Identify characteristics of acids & bases.

• Compare acids & bases.

Acids and Bases

• Produce H+ ions in water

• Have a sour taste• Break down metals• Poisonous and

corrosive to skin• Formula starts with H• pH less than 7

• Produce OH- ions in water

• Have a bitter taste and a slippery feel

• Break down fats and oils

• Poisonous and corrosive to skin

• Formula ends with OH• pH greater than 7

Acids and Bases

• ACIDS

Examples: vinegar, lemon juice, aspirin, stomach acid, battery acid, cola,

• BASES

Examples: soap, shampoo, ammonia, drain cleaner, antacids

milk

Acids

• An acid is a substance that ionizes in water to produce hydrogen ions (H+)

• Strength– Strong acids completely ionize in water. – Weak acids ionize only slightly.

Base

• A base is a substance that ionizes in water to produce hydroxide ions (OH-)

• Strength– Strong bases ionize completely. – Weak bases do not.

Basic Acidic Neutral

H+

H+

H+OH-

OH-

OH-

Solution Solution Solution

Which solution is Acidic? Basic? Neutral???

pH Scale• Numeric scale that tells the acidity or

basicity (alkalinity) of substances.

0 7 14

Strong Acid Weak Acid Neutral Weak Base Strong Base

Neutralization Reactions

• When an acid is added to a base, they neutralize each other. (ie, the end products are neutral)

• Acid + Base Salt + Water

HCl + NaOH NaCl + H2O

H2SO4 + Al(OH)3 Al2(SO4)3 + H2O

• Salt – the neutral product of an acid/base rxn

pH Indicators• Chemical substance that changes color in an

acid or a base.

• pH paper; – paper strips dipped in universal indicator;

• red in acid,

• green in neutral substance,

• purple in base

• match the color to a number on the vial to determine pH

Litmus Test• Litmus paper; paper strips dipped in red and blue

litmus;• Tells definitively whether the substance is an acid

or base. “Litmus Test”• Dip one red and one blue strip & check results:

Red → Red = Acid

Blue → Red = Acid

Red → Blue = Base

Blue → Blue= Base

Red → Red = Neutral

Blue → Blue= Neutral

Other pH indicators• Phenolthalein

– Pink – pH is greater than 9– Clear – pH is lower than 9– Only indicates strong bases

• Strong Base – Pink• Weak Base – Clear• Neutral – Clear • Weak Acid – Clear• Strong Acid – Clear

• Bromothymol Blue– Base – Blue– Neutral – Green– Acid – Yellow