1. Chemistry in the Kitchen
Unit 3:
Acids & Bases pH
Reactions with Metals
Neutralization Reactions

2. Electrolytes
Ionic
Covalent
C6H12O6
Na+
NaCl
Cl-

3. Acids Strong Weak HC2H3O2 H-Cl C2H3O21- Cl- H+ H+ Only a few Ions
Lots of Ions

4. Acid = gives hydrogen ions in water
Acids
Acid = gives hydrogen ions in water
HCl
H+ + Cl- H+
H-Cl
Cl-
hydrogen ion

5. Acid = gives hydrogen ions in water
Acids
Acid = gives hydrogen ions in water
H-Cl H-O-H
Cl-
H-Cl
+ Cl-
hydronium ion

6. Common Acids Strong Weak H2SO4 Battery Acid HCl Stomach Acid
H3PO4
H2CO3
HC2H3O2
H3C6O7H8
HC6O6H7
H2C4O6H4
H2C9O4H8
Battery Acid
Stomach Acid
Coca Cola
Carbonated Water
Vinegar
Citrus fruits
Vitamin C
Grapes
Aspirin
Strong
100% ionization
Strong electrolyte
Weak
Partial ionization
Weak electrolyte
Taste sour

7. Acids H-Cl + H-O-H + Cl- H-C2H3O2 + H-O-H + C2H3O2- H-Cl HC2H3O2 Cl-

8. Bases Base = gives hydroxide ions in water.
(Arrhenius definition)
= takes hydrogen ions in water.
(Bronsted-Lowry definition)
OH-
Na+
NaOH
NaOH
Na+ + OH-

9. Common Bases Lye, Drano Potash Cleaners Baking soda Tums /Rolaids
Milk of Magnesia
Baking soda
Tums /Rolaids
Limestone, shells
Soaps
Detergents
Amines (Alkaloids)
NaOH
KOH
NH3 or NH4OH
Mg(OH)2
NaHCO3
CaCO3
NaC16O2H31
NaC12O4H25S
R-NH2
Sodium Hydroxide
Potassium Hydroxide
Ammonia
Magnesium Hydroxide
Sodium Bicarbonate
Calcium Carbonate
Sodium Palmitate
Sodium Lauryl Sulfate
Caffeine, Nicotine

10. Common Bases Strong Weak 100% ionization Strong electrolyte
Lye, Drano
Potash
Cleaners
Milk of Magnesia
Baking soda
Tums /Rolaids
Limestone, shells
Soaps
Detergents
Amines (Alkaloids)
NaOH
KOH
NH3 or NH4OH
Mg(OH)2
NaHCO3
CaCO3
NaC16O2H31
NaC12O4H25S
R-NH2
Strong
100% ionization
Strong electrolyte
Weak
Partial ionization
Weak electrolyte
Taste bitter
Feel Slippery

11. Water is Amphoteric: (Acid or Base)
HNO3
HNO3 + H-O-H NO3-
Acid
donates
an H+
Base
takes
an H+
Acid
Base
NH3
Acid
donates
an H+
Base
takes
an H+
Base
takes
an H+
Acid
donates
an H+

12. Ionization of Water
H2O H2O HO H3O+
Base
Acid
Acid
Base

13. Ionization of Water H2O + H2O HO- + H3O+ Neutral: if [H3O+] = [OH-]
BASE
ACID
ACID
BASE
0.000,000,1M
= 1 x 10-7M
0.000,000,1M
= 1 x 10-7M
Neutral: if [H3O+] = [OH-]
Acidic: if [H3O+] > [OH-]
Basic: if [H3O+] < [OH-]

14. pH HCl HC2H3O2 H2O NH3 NaOH -2 Acidic 4 7 Neutral NaHCO3 8 Basic 9 12
= 1 x 10 -pH
pH = - log [H+]
HCl
HC2H3O2
Vinegar
H2O
NH3
NaOH
100 M
= 1 x 10 2 M
0.000,000,1 M
= 1 x M -2
Acidic
0.000,1 M
= 1 x M 4 7
Neutral
NaHCO3
Baking Soda
0.000,000,01 M
= 1 x M 8
0.000,000,001 M
= 1 x M
Basic 9
0.000,000,000,001 M
= 1 x M 12

15. pH HCl HC2H3O2 H2O NaOH -2 Acidic 4 7 Neutral NaHCO3 8 Basic 12 [H+]
= 1 x 10 -pH
pH = - log [H+]
HCl
HC2H3O2
vinegar
H2O
NaOH
100 M
= 1 x 10 2 M
0.000,000,1 M
= 1 x M -2
Acidic
0.000,76 M
= 7.6 x M
Citric Acid
0.000,1 M
= 1 x M 4 7
Neutral
NaHCO3
Baking Soda
0.000,000,01 M
= 1 x M 8
Basic
0.000,000,000,001 M
= 1 x M 12

16. pH 3 HC2H3O2 3 - 4 0.000,76 M = 7.6 x 10 -4 M 4 [H+] = 1 x 10 -pH
pH = - log [H+]
HC2H3O2
0.001 M
= 1 x M 3
3 - 4
0.000,76 M
= 7.6 x M
pH =
- log (7.6 x 10 -4)
Citric Acid
= 3.1
0.000,1 M
= 1 x M 4

17. pH Indicators Pigments: pH meter: pH paper: Litmus paper:
Anthocyanins:
red cabbage, cranberries, roses…
Phenolphthalein:
Turmeric:

18. Anthocyanin Pigments Food source Anthocyanin content in mg per 100 g
Açaí
320
Blackcurrant
Chokeberry
1,480[8]
Eggplant
750
Blood orange
~200
Marion blackberry
317[9]
Black raspberry
589[10]
Raspberry
365
Wild blueberry
558[11]
Cherry
Redcurrant
80-420
Purple corn
1,642[12

19. Anthocyanin Pigments Food source Anthocyanin content in mg per 100 g
Açaí
320
Blackcurrant
Chokeberry
1,480[8]
Eggplant
750
Blood orange
~200
Marion blackberry
317[9]
Black raspberry
589[10]
Raspberry
365
Wild blueberry
558[11]
Cherry
Redcurrant
80-420
Purple corn
1,642[12
Anthocyanin Pigments

20. Anthocyanin Pigments

21. Chlorophyll Color Changes of Chlorophyll in Response to Changes in pH
Under more or less neutral conditions, chlorophyll has its normal vegetable green color (think of raw green beans or broccoli)
Chlorophyll

22. Color Changes of Chlorophyll in Response to Changes in pH
Under acidic conditions, the magnesium atom (Mg+2) is lost and the color changes to the characteristic pheophytin olive green color.
No Mg+2
atom
Pheophytin

23. Color Changes of Chlorophyll in Response to Changes in pH
Under alkaline conditions the methyl and phytyl esters are removed, producing chlorophyllin which is a bright green color.
No ester
groups
Chlorophyllin

24. Color Changes of Chlorophyll in Response to Changes in pH
Chlorophyllase
Other reactions, mediated by the enzyme chlorophyllase, may result in changes in the pigment, even under conditions of frozen storage.
This is why such vegetables (green beans, broccoli, etc.) are blanched (put briefly in boiling water) before preservation by freezing. This destroys the enzyme activity.

25. Acid Reactions
HCl + Zn 
ZnCl2 + H2
Acid
Metal
Salt H+
Cl- Zn

26. Activity series of metals - various metals in HCl
Iron Zinc Magnesium

27. Activity series of metals
potassium
sodium
calcium
magnesium
aluminum
zinc
chromium
iron
nickel
tin
lead
copper
silver
platinum
gold
Reacts violently with cold water
Reacts slowly with cold water
Reacts very slowly with steam
but quite reactive in acid
increasing reactivity
Reacts moderately with high
levels of acid
Hydrogen (acid)
Unreactive in acid

28. Carbonated beverages in coated cans Al foil on lazagna Pineapple in tin vs Al Tin coated with plastic Al pop cans coated w plastic Grape juice in glass

29. Acid-Base Reactions HCl + NaOH  NaCl + HOH Neutralization: Water Acid
Salt
Neutralization:
Strong Acid +
Strong Base H+
Cl-
Na+
OH-

30. Acid-Base Reactions 2 2 H2SO4 + KOH  K2SO4 + HOH Water Acid Base Salt

31. Acid-Base Reactions HC2H3O2 + NaHCO3 Acid Base NaC2H3O2 + H2CO3 Salt
Vinegar & Baking Soda
HC2H3O2 + NaHCO3
Acid
Base
NaC2H3O2 + H2CO3
Salt
C2H3O21- H+
H2O + CO2(g)
Na+
HCO31-

32. Acid-Base Reactions Cream of Tartar & Baking Soda Acid Rain on Marble
HC2H3O2 + NaHCO3
NaC2H3O2 + H2CO3
Acid
Base
Salt
H2O + CO2(g)
Acid Rain on Marble
H2SO CaCO3
CaSO H2CO3
Acid
Base
Salt
H2O + CO2(g)

33. Acid-Base Reactions Lemon on Fish H3C6H8O7 + R-NH2 C6H8O71- + R-NH31+
Salt