Chemistry - 11 Acids and Bases

Lowry Bronsted’s definition of Acids

Acids are substances that dissociate (break apart) and ionise (form ions) in water to produce hydrogen ions (H+)

• donates a proton to a base

Lowry Bronsted’s definition of Bases

Bases dissociate in water to produce Hydrioxide ions (OH-)

• accepts a proton

Conjugate Base

what remains after an acid donates a proton (H⁺) in a chemical reaction
HCL becomes Cl-

Conjugate Acid

when a base gains a proton (H⁺)
NH3 accepts proton, turns into NH4

Ionisation Equation

reaction of acids or bases with water

Amphiprotic

substances that can behave as acids or bases depending on what they’re reacting with
H2PO4-, H20, HSO4-

Monoprotic Acids

donate only 1 proton

• HCL, HNO3, CH3COOH

Polyprotic Acids

donate more than 1 proton from each molecule, in steps (not all at once)
H2SO4, H3PO4

Diprotic Acids

• donate 2 protons

• ionises in 2 stages

H2SO4

Triprotic Acids

• donate 3 protons

• ionises in 3 stages

H3PO4

Properties of Acids

turns litmus indicator red

tend to be corrosive

tastes sour

reacts with bases

solutions have a relatively low pH

solutions conduct an electric current

Properties of Bases

turn litmus indicator blue

are corrosive, caustic, and slippery

taste bitter

react with acids

solutions have a relatively high pH

solutions conduct an electric current

Acids and Metal Hydroxides

acid + metal hydroxide > salt + water

Acids and Metal Carbonates

acid + metal carbonate > salt + water + carbon dioxide

Acids and Reactive Metals (ZAM)

acid + reactive metsl > salt + hydrogen

Water is an…

amphiprotic substance, and can self ionize/react with itself

at 25C the ionic product of water is…

Kw= 10 to the power of -14

Acidic basic and neutral solutions can be defined as

ACIDIC IF        [H₃O⁺ ]  >   10^-7M  and  [OH-]  < 10^-7M 

BASIC IF          [H₃O⁺ ]  <   10^-7M  and  [OH-]  > 10^-7M 

NEUTRAL IF     [H₃O⁺ ]  =   10^-7M  and  [OH-]  = 10^-7M 

C/V/N triangle is..

n
c v

new triangle is….

10 to power of -14
[OH-] [H3O+]

Indicators

PLANT EXTRACTS SUCH AS RED CABBAGE, LITMUS AND OTHER CHEMICALS THAT ARE WEAK ACIDS THAT CAN CHANGE COLOUR IN THE PRESENCE OF ACIDS AND BASES