Acid and Bases

Physical Properties

AcidTaste sourCitric Acid and

Ascorbic: lemonsCarbonic and

Phosphoric: carbonated beverages

Acetic Acid: vinegarConduct electricity

BaseTaste bitter Feel slippery: wet soapConduct electricity

Chemical Properties

• Reactions• Litmus paper• Red = Acidic• Blue = Basic

• Reactions• Metals and Metal

Carbonates

• Produce H2 or CO2

• Geologists identify limestone with hydrochloric acid

Videos

Links on DHS Chemistry blog

Ions

Hydrogen Ion H+

Sometimes H3O+

Hydroxide OH-

Hydrogen Bond

Goes back and forth

NoticeExponent on 10Is opposite of pH

pH = - log [H+]

pOH = -log [OH-]

Think in termsof the base

pOH [OH-] 14 1 x 10-14

7 1 x 10-7

0 1 x 100

pH + pOH = 14

Water gains H+

Water loses H+

Neutralization

Base + Acid Salt + Water

HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l)

What type of compounds are each?

Acid Neutralizers

Limestone

Oceans and Acid Rain

Calcium carbonate CCaO3

Sometimes antacids can interfere with medications

Acid Base Reaction then DecompositionWhy do some breads have holes?

HC2H3O2(aq) + NaHCO3aq) NaC2H3O2(aq) + H2CO3(aq) H2CO3(aq) CO2(g) + H2O(l)

Practice

Write the balanced equation for the reaction between zinc and nitric acid.

Write the balanced equation for the reaction between magnesium carbonate and sulfuric acid.

Answers

Zn(s) + 2HNO3(aq) Zn(NO3)2(aq) + H2(g)

MgCO3(s) + H2SO4(aq) MgSO4(aq) + H2O(l) + CO2(g)

How do you know if you get hydrogen gas or carbon dioxide gas?

Practice

Identify the base in the reaction.

H2O(l) + CH3NH2(aq) OH-(aq) +CH3NH3+(aq)

• The base is CH3NH2(aq)• The reactants have an acid and a base• The products have conjugate pairs – match

up (think Alg 2)• There is an OH- ion in the products which is

the conjugate (or pair) base• What did the OH- start as? This is the

acid (opposite of base)• So, the other compound must be the base.

Practice

Is the solution in which [H+] = 1.0 x 10-5M acidic, basic or neutral?

Is the solution in which [OH-] = 1.0 x 10-11M acidic, basic or neutral?

Answers

Is it H+ or OH-?

• H+ so low pH is more acidic, pH = 5, <7 so slightly acidic

• OH- so low pOH is basic, pOH = 11, >7 so strong acidic

Or, think pH = 14 – pOH so pH = 3, strong acid

Practice – Neutralization

Write the formula equation for the reactions between hydrioric acid and beryllium hydroxide.

Write the formula equation for the reactions between perchloric acid and lithium hydroxide.

hydrioric acid and beryllium hydroxide

Hyrd = hydrogen =H

ioric = iodine = I

Covalent bonding, share 1 e-

Beryllium = Be is group 2 so 2+

Hydroxide = OH- is 1- so need 2

Ionic bonding, metal and ion

HI

Be(OH)2

perchloric acid and lithium hydroxide

Chloric = Chlorine and Oxygen and acid so need Cl and O and H (need a list of common acids)

Lithium = Li is group 1 so 1+

hydroxide = OH- so need 1

Ionic bonding, metal and ion

LiOH

HCIO4

Answers

2HI(aq) + Be(OH)2(aq) BeI(aq) + 2H2O(l)Think how many water? So balance the H

HCIO4(aq) + LiOH(aq) LiCIO4(aq) + H2O(l)

Keep the ClO4 as a unit even if it does not have ( )