Vocabulary

• Hydronium = H3O+

• Proton = H+ or H3O+

• Hydroxide = OH-• Amphoteric = a compound that can act as an acid

or base.• Alkaline = When a base completely disassociates in

water to yield OH- ions.

H2OHCl H+ + Cl-

Acid is a proton donor (H+), which creates hydronium ions.

H2ONaOH Na+ + OH-

A base is a proton acceptor

Acid

• Bronsted-Lowry – H+ (proton) donor (doesn’t have to happen in an aqueous solution)

– Ex., HCl + NH3NH4+ + Cl-

• Arrhenius – produce H+ in aqueous solution• [H+] > [OH-]

Base

• Bronsted-Lowry – H+ (proton) acceptor• Arrhenius – produce hydroxide (OH-) in an aqueous solution• [H+] < [OH-]

A c i d a n d B a s e S t r e n g t h–– S t r o n g a c i d :S t r o n g a c i d : o n e t h a t r e a c t s c o m p l e t e l y o r a l m o s t c o m p l e t e l y

w i t h w a t e r t o f o r m H 3 O + i o n s

–– S t r o n g b a s e :S t r o n g b a s e : o n e t h a t r e a c t s c o m p l e t e l y o r a l m o s t c o m p l e t e l y w i t h w a t e r t o f o r m O H - i o n s

– h e r e a r e t h e s i x m o s t c o m m o n s t r o n g a c i d s a n d t h e f o u r m o s t c o m m o n s t r o n g b a s e s

H C lH B rH IH N O 3

H 2 S O 4

H C lO 4

L iO HN a O HK O H

B a ( O H ) 2

H y d r o c h l o r i c a c i dH y d r o b ro m i c a c i dH y d r o i o d i c a c i dN i t r ic a c i dS u l f u ri c a c i dP e r c h l o r i c a c i d

L i t h iu m h y d ro x i d eS o d i u m h y d r o x i d eP o t a s s iu m h y d ro x i d eB a r i u m h y d ro x i d e

F o r m u l a N a m e F o r m u l a N a m e

http://www.chem.utk.edu/yang/chap8.ppt

Strong AcidsChloric Acid HClO3

Hydrobromic Acid HBrHydrochloric Acid HClHydriodic Acid HINitric Acid HNO3

Perchloric Acid HClO4

Sulfuric Acid H2SO4

Hydronium Ion H3O+

Strong Bases

Carbonate Ion CO2/3 -

Phosphate Ion PO3/4-

Hydroxide Ion OH-

Amide Ion NH2-

Hydride Ion H-

A c i d a n d B a s e S t r e n g t h•• W e a k a c i d :W e a k a c i d : a s u b s t a n c e t h a t d i s s o c i a t e s o n l y p a r t i a l l y i n w a t e r

t o p r o d u c e H 3 O + i o n s

– a c e t i c a c i d , f o r e x a m p l e , i s a w e a k a c i d ; i n w a t e r , o n l y 4 o u t e v e r y 1 0 0 0 m o l e c u l e s a r e c o n v e r t e d t o a c e t a t e i o n s

•• W e a k b a s e :W e a k b a s e : a s u b s t a n c e t h a t d i s s o c i a t e s o n l y p a r t i a l l y i n w a t e r t o p r o d u c e O H - i o n s

– a m m o n i a , f o r e x a m p l e , i s a w e a k b a s e

C H 3 C O O H ( a q ) + H 2 O ( l ) C H 3 C O O - ( a q ) + H 3 O + ( a q )A c e t i c a c i d A c e t a t e i o n

N H 3 ( a q ) + H 2 O ( l ) N H 4+ ( a q ) + O H - ( a q )

http://www.chem.utk.edu/yang/chap8.ppt

Conjugate acid – base pair

HCl(aq) + H2O(l) H3O+(aq)+Cl-(aq)

WaterHydrogenchloride

Hydroniumion

Chlorideion

(base)(acid) (conjugateacid of water)

(conjugatebase of HCl)

conjugate acid-base pair

conjugate acid-base pair

–Conjugate acid-base pair:Conjugate acid-base pair: any pair of molecules or ions that can be interconverted by transfer of a proton

http://www.chem.utk.edu/yang/chap8.ppt

In the reaction of a Bronsted-Lowry acid, the molecule or ion that remains is the conjugate base.

Neutralization Reactions

• Occurs in an aqueous solution between a strong acid and a strong base.

• When neutralization occurs, a salt and water are formed.

• Ex., HCl + NaOH H2O + NaCl

• Lewis Acid- an atom, ion or molecule that accepts an electron pair to form a covalent bond.

• Applies to any ion that can accept an electron pair.

• H+ +2:NH3 [H-NH3]+ or [NH4]+

• A Lewis base is an atom or molecule that donates an electron pair to form a covalent bond.

Net Ionic Equations• A net ionic equation includes only those

compounds and ions that undergo a chemical change.– Write an overall ionic equation– All soluble compounds are shown as

dissociated ions in solution, ppt are shown as solids.

– Ex., ppt of cadmium sulfate

Cd2+ (aq) + 2NO3- + 2NH4

+(aq) SO42- CdSO4(s)

+ 2NO3-(aq) +2NH4

+(aq)

Net Ionic Equation

• Cd2+(aq) + SO4 2-(aq) CdSO4(s)

HCl + H2O H3O+ + Cl-

(acid) (base) (conjugate acid) (conjugate base)

Water can be both a acid and a base

H2O + H2O H3O+ + OH-

The animation here shows the formation of H3+O

ions and OH- ions in an aqueous system

Kw = ion-product constant

• Kw = in any aqueous solution @ 25 degrees Celcius the product of [H3O+][OH-] must always equal 1.0 X 10-14

[H +] = [OH-] = 1.0 * 10-7

Kw = [H+] [OH-] = (1.0 *10-7)(1 *10 -7)Kw = 1.0 * 10-14

Calculating pH and pOHNext let's look at values for pH and pOH. pOH is simply

the power of hydroxide ion concentration and is figured the same way as pH but using the concentration

of hydroxide ion instead.)

Source: http://dl.clackamas.cc.or.us/ch105-05/calculat1.htm

Let's start by working with the concentrations that are 1.0 x 10(raised to some power). These pH and pOH values can be figured very simply. When [H3O

+] is 10-7 M, the pH is 7. Also the [OH-] is 10-7 M and the pOH is 7. Note that the pH and pOH add up to 14.

pH [H3O+] [OH-] pOH

 

7 1.0 x 10-7 M 1.0 x 10-7 M 7

Now look at the acidic solutions. When the [H3O

+] is 10-6 M, the pH is 6. Also, the [OH-] is 10-8 M and the pOH is 8. Again, the pH and the pOH add up to 14. When the [H3O

+] is 10-5 M, pH is 5, [OH-] is 10-9 M, and pOH is 9. pH + pOH = 14.

65

1.0 x 10-6 M 1.0 x 10-5 M

1.0 x 10-8 M 1.0 x 10-9 M

89

pH [H3O+] [OH-] pOH

Next, the basic solutions. When [OH-] is 10-6 M, the pOH is 6. Since [H3O

+] 10-8 M, the pH is 8. When [OH-] is 10-5 M, and [H3O

+] is 10-9 M, the pOH is 5 and pH is 9. Again in both cases the sum of pH and pOH is 14.

89

1.0 x 10-8 M 1.0 x 10-9 M

1.0 x 10-6 M 1.0 x 10-5 M

65

pH [H3O+] [OH-] pOH

However, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. For example, we skipped over the value of 2.0 x 10-7. This is more complicated. However, if you use a calculator that will handle logarithms, it is a very simple calculation. First you enter the hydronium ion concentration. You can use decimal format or scientific notation. Next push the log button. Then change the sign by pushing the +/- button. In this case we get 6.70 for the pH. The other values can be obtained in the same way.

6.707.30

2.0 x 10-7 M 1.0 x 10-7 M

1.0 x 10-7 M 2.0 x 10-7 M

7.306.70

pH [H3O+] [OH-] pOH

PH Scale

PH = -log [H+]

Step 1 : Enter [Molarity of H+]Step 2 : Press “log” and hit +/- key

Reverse for graphing calculator

More vocabulary• Diprotic Acid

• H2CO3   =    H+  +    HCO3-

• HCO3-   =   H+  +    CO3

-2   

• Triprotic acid– H3PO4+H2O-->H3O+H2PO4

– It's second ionization: H2PO4+H2O-->H3O+HPO4

– It's third ionization: HPO4+H2O-->H3O+PO4

• Oxyacid – compound of H, O, and a third element usually a nonmetal. Ex HNO3

• Organic acid – has a carbon