1. Acids & Bases and Functional Groups

2. I. Water pH is neutral
A. We know that water is a polar molecule composed of oxygen and hydrogen.
B. We also know that water is a great solvent since it is charged and always can dissolve solutes that have a slight charge
C. Water can also be considered to be a hydrogen ion (H⁺) and a hydroxide ion (OH⁻).
1. One water molecule in about 550 million reacts and forms these ions

4. I. Water pH is neutral
D. Because the number of positive hydrogen ion (H⁺) equals the number of negative hydroxide ion (OH⁻) water is neutral.

5. II. The pH Scale
A. pH scale is a measurement system that indicates the concentration of H⁺ ions in a solution.
B. The scales reads from 1-14
1. pH of 7 has equal number of H⁺ and OH⁻.
2. pH of less than 7 is acidic and has more H⁺ than OH⁻
3. pH of more than 7 is basic and has more OH⁻ than H⁺

7. II. The pH Scale cont.
C. The lower the number the more acidic the solution is; the higher the number the more basic the solution is.
Strong acids pH = 1-3, Strong bases pH = 11-14
D. Each step on the pH scale represents a factor of 10.
1. pH of 4 has 10 times the number of H⁺ than a pH of 5

8. Acids release H⁺ in the solution
Bases release OH⁻ in the solution

10. III. Characteristics Acids are usually sour to the taste
EX. Orange juice
Bases are bitter
EX. Mustard

11. Litmus Paper
Litmus- paper that changes color due to the H ions in a solution

12. IV. Buffers
A. Our cells need to be at a constant pH of 6.5 to 7.5 if it changes drastically the chemical reactions that take place would be greatly affected.
B. Controlling the pH is very important to maintain homeostasis.
C. Buffers are weak acids & bases that react with strong ones to prevent drastic changes
Example: Ammonium hydroxide & Acetic acid

13. Functional Groups
Functional groups are groups of elements responsible for the chemical properties of organic compounds.
There are SIX groups to remember:
Amino group
Carbonyl group
Carboxyl group
Hydroxyl group
Phosphate group
Sulfhydryl group

14. Amino Group (aka amines)
In the amino group, NH2 is attached to a compound (R = rest of compound)
Function: act as bases and pick up protons from acids
Examples: amino acids

15. Carbonyl Group There are two structures in the carbonyl group:
If C = O at the end of a chain, it is an aldehyde
Otherwise, it is a ketone
Function: carbonyl groups make a compound hydrophilic and polar (react well to water)

16. Carboxyl Group Carbonyl group + OH = Carboxyl group
Function: act as acids (donate protons to bases)
Example: Carboxylic acid

17. Hydroxyl Group (aka alcohols)
OH attached to the rest of compound
Polar and hydrophilic
Functions: Make molecules soluble in water
Example: Ethanol

18. Phosphate Group Acidic
Functions: vital components of nucleic acids and compounds that serve as cellular energy sources
Example: ADP, ATP, GTP and DNA or RNA

19. Sulfhydryl Group Sulfur and Hydrogen attached to rest of compound
Function: Assists in structure stabilization in many proteins
Examples: Present in amino acids such as methionine and cysteine