Ions in solution, acids bases and salts.

Acid and based

1. ACIDS AND BASES
Unit VII

2. I ELECTROLYTES
An electrolyte is a compound, that when dissolved in
water, conducts electricity
How?
Ions (charges) produced are free to move
Movement of charge is conductivity
Examples
Acids
Bases
“Salts”
Soluble Ionic compounds

3. II PROPERTIES
Acids
Good conductors
Dissolve metals
Table J--Metals above “H
2
” dissolve in acid
Taste sour
Turns litmus paper red
Turns phenolphthalein clear

4. II PROPERTIES
Bases
Good conductors
Dissolve fats
Feels slippery
Taste bitter
Turns litmus paper blue
Turns phenolphthalein pink

5. III DEFINITIONS
A.Arrhenius
Acids
An Arrhenius acid contains H
+
ions
When dissolved in water these H
+
ions combine to
form hydronium ion (H
3O
+
)
Examples: HCl H
2
SO
4
HC
2
H
3
O
2
Bases
An Arrhenius base contains OH
-
ions (hydroxide ion)
bonded to NH
4
+
or a metal
Examples: NaOH Ca(OH)
2

6. III DEFINITIONS
B. Brönsted-Lowry
Acids
A Brönsted-Lowry acid loses or donates protons to its
conjugate (substance that differs by an H
+
)
HCl + NH
3 → Cl
-
+ NH
4
+
HCl and Cl- are conjugate pairs; HCl is the acid
and Cl
-
is its conjugate base
Bases
A Brönsted-Lowry base gains or accepts protons from its
conjugate
HCl + NH
3 → Cl
-
+ NH
4
+
NH
3
and NH
4
+
are conjugate pairs; NH
3
is the base
and NH
4
+
is its conjugate acid

7. IV NOMENCLATURE
A. Naming Compounds
Binary Acids
A binary acid contains hydrogen and a nonmetal
To name a binary acid
Use “hydro-”
Add nonmetal root word
End with “ic acid”
Ex. HCl
Hydrochloric acid
Ex. H
2
O
Hydroxic acid

8. IV NOMENCLATURE
Ternary Acids
A ternary acid contains hydrogen and a polyatomic
ion
To name a ternary acid
Determine the polyatomic that is present
using Reference Table E
If the polyatomic ion ends in “ate” change the
ending to “ic”
If the polyatomic ion ends in “ite” change the
ending to “ous”
Ex. HClO
3
Chlorate becomes Chloric acid (no hydro is used)
Ex. HNO
2
Nitrite becomes Nitrous acid

9. IV NOMENCLATURE
Bases
To name a base, name as you would any compound
Write the first element
Write the polyatomic
Add a Roman numeral if needed
Ex. NaOH
Sodium hydroxide
Ex. Cu(OH)
2
Copper II hydroxide

10. IV NOMENCLATURE
B.Writing Formulas
- Acids
•If binary
•Write H
+
and the other element present
•Assign charges and criss-cross
Ex. Hydrochloric acid
H
+1
Cl
-1
HCl

11. IV NOMENCLATURE
•If ternary
•Identify the polyatomic present using ending
•Write H
+
and the polyatomic ion
•Assign charges and criss-cross
•Ex. Chloric acid
•chloric comes from chlorate
ClO
3
-1
•H
+1
ClO
3
-1
•HClO
3

12. V REACTIONS
A Neutralization
Mixing of acid and base
HCl + NaOH →
Makes salt and water
Break (ionize) the acid and base
H
+1
Cl
-1
Na
+1
OH
-1
Join H to OH (H
2
O)
Join metal to nonmetal (assign charges and crisscross)
HCl + NaOH → H
2O + NaCl

13. Lab technique for neutralization is called Titration
Occurs when moles of acid equals moles of base
For 1:1 acid–base reactions
Moles acid = Moles base
M
A
V
A
= M
B
V
B

14. EXAMPLES OF TITRATION PROBLEMS
Given the balanced equation:
HCl + NaOH H
→
2O + NaCl
How many milliliters of 3.0M NaOH are needed to neutralize
20 milliliters of 2.5M HCl?
M
B
= 3.0M NaOH
M
A= 2.5M HCl
V
A= 20 mLs HCl
Ratio is 1:1 so M
AV
A = M
BV
B can be used
2.5M x 20 mLs = 3.0M x V
B
50 = 3V
B
 V
B=16.7 mLs NaOH

15. EXAMPLES OF TITRATION PROBLEMS
Given the balanced equation:
H
2SO
4 + 2 NaOH 2 H
→
2O + Na
2SO
4
How many milliliters of 1.2 M NaOH are needed to
neutralize 23 milliliters of 1.9 M H
2SO
4?
M
B= 1.2 M NaOH
M
A= 1.9 M H
2SO
4
V
A= 23 mLs H
2SO
4
Ratio is NOT 1:1 so M
A
V
A
= M
B
V
B
CANNOT be used
23mL H
2SO
4 x 1L x 1.9 mole H
2SO
4 x 2 mole NaOH x 1L x 1000 ml
1000 mL 1 L 1 mole H
2SO
4 1.2 mole NaOH 1L
V
B
= 72.8 mLs NaOH

16. IV REACTIONS
B Hydrolysis
Mixing of salt and water
Makes parent acid and base of the salt
NaCl + HOH →
HCl + NaOH
Reverse of neutralization

17. VI STRENGTH
Acid and base strength depend on number of ions in solution
More ions; stronger acid or base
Some acids ionize 100% (strongest acids)
HCl HBr HI
H
2
SO
4
HNO
3
HClO
4
Some bases ionize 100% (strongest bases)
LiOHNaOHKOH
RbOHCsOHNH
4
OH

18. A.pH
Every aqueous solution contains H
+
and OH
-
•Acids have more H
+
than OH
-
•Bases have more OH
-
than H
+
pH represents the amount of H
+
in a solution
1 7 14
Strong Weak Neutral Weak Strong
acid acid base base
Most H
+
Equal H
+
and OH
-
Least H
+
Least OH
-
Most OH
-

19. pH Scale is logarithmic
•Values change by factors of 10
•ex. pH = 3 vs. pH = 5
•Difference in pH
•2 units
•10 x 10
•pH 3 is 100 times stronger than pH 5
•pH 5 is 1/100
th
as strong as pH 3

20. B.Acid Base Indicators
Compounds that change color over pH ranges
Table M Common Acid–Base Indicators
• methyl orange 3.2–4.4 red to yellow
• bromthymol blue 6.0–7.6 yellow to blue
• phenolphthalein 8.2–10 colorless to
pink
• litmus 5.5–8.2 red to blue
• bromcresol green 3.8–5.4 yellow to blue
• thymol blue 8.0–9.6 yellow to blue