CHAPTER 7: Organic Functional Groups
PRACTICE PROBLEM
Epinephrine (adrenaline) is a hormone secreted when the body is under
stress. Illicit drugs that are structurally similar to epinephrine are highly
addictive stimulants. For example, the illegal and addictive drug
methamphetamine is similar in structure to epinephrine. However,
pseudoephedrine, which is structurally similar to epinephrine, is a
decongestant and sold over the counter in pharmacies.
a. Circle and label all the amine functional groups in these
molecules.
b. In what way is methamphetamine structurally similar to
pseudoephedrine? How is it different?
c. In the body, the amine in epinephrine is in its ionic form. Write the
structure of the ionic form of epinephrine.
CHAPTER 7: Organic Functional Groups
PRACTICE PROBLEM
Epinephrine (adrenaline) is a hormone secreted when the body is under
stress. Illicit drugs that are structurally similar to epinephrine are highly
addictive stimulants. For example, the illegal and addictive drug
methamphetamine is similar in structure to epinephrine. However,
pseudoephedrine, which is structurally similar to epinephrine, is a
decongestant and sold over the counter in pharmacies.
a. Circle and label all the amine functional groups in these
molecules.
b. In what way is methamphetamine structurally similar to
pseudoephedrine? How is it different?
c. In the body, the amine in epinephrine is in its ionic form. Write the
structure of the ionic form of epinephrine.
Saponification
Reaction converting fats to soap with glycerol as a
byproduct
Involves base hydrolysis
Reaction with NaOH
Saponification
(CH3CH2CH2CH2CH2CH2CH2COOCH
2)3CH
(CH3CH2CH2CH2CH2CH2CH2COOCH
2)3CH
+
CH3CH2CH2CH2CH2CH2CH2CO
O- Na+
3 NaOH Æ
3
C3H8O3
CH3CH2CH2CH2CH2CH2CH2CO
O- Na+
+
C3H8O3
Saponification
(CH3CH2CH2CH2CH2CH2CH2COO
CH2)3CH
MW = 420.29
+
3 NaOH Æ
MW = 40
3
CH3CH2CH2CH2CH2CH2CH2CO
O- Na+
+
MW = 166.07
1) What is the theoretical yield for the soap product if 5g of triglyceride react? OR
(same question)
CH3CH2CH2CH2CH2CH2CH2
How many grams of COO- Na+
are produced by reacting
5.0 grams of
(CH3CH2CH2CH2CH2CH2CH2COO
CH2)3CH
2) If 4.0 grams of
CH3CH2CH2CH2CH2CH2CH2
COO- Na+
then what is the percent yield?
with excess NaOH?
are recovered after the reaction,
C3H8O3
MW = 92.11
Saponification
(CH3CH2CH2CH2CH2CH2CH2COO
CH2)3CH
MW = 420.29
+
3 NaOH Æ
MW = 40
3
CH3CH2CH2CH2CH2CH2CH2CO
O- Na+
+
MW = 166.07
1) What is the theoretical yield for the soap product if 5g of triglyceride react? OR
(same question)
CH3CH2CH2CH2CH2CH2CH2
How many grams of COO- Na+
are produced by reacting
5.0 grams of
(CH3CH2CH2CH2CH2CH2CH2COO
CH2)3CH
2) If 4.0 grams of
CH3CH2CH2CH2CH2CH2CH2
COO- Na+
then what is the percent yield?
with excess NaOH?
are recovered after the reaction,
C3H8O3
MW = 92.11
Saponification
(CH3CH2CH2CH2CH2CH2CH2COOCH
2)3CH
+
3 NaOH Æ
MW = 420.29
How many grams of
5.0 grams of
MW = 40
CH3CH2CH2CH2CH2CH2CH2
COO- Na+
(CH3CH2CH2CH2CH2CH2CH2COOCH
2)3CH
3
CH3CH2CH2CH2CH2CH2CH2CO
O- Na+
MW = 166.07
CH3CH2CH2CH2CH2CH2CH2
COO- Na+
C3H8O3
MW = 92.11
are expected to be produced by reacting
with excess NaOH?
Answer: 5.9 grams
If 4 grams of
+
are recovered after the reaction,
then what is the percent yield?
Answer: 67.8 %
Saponification
(CH3CH2CH2CH2CH2CH2CH2COO
CH2)3CH
MW = 420.29
+
3 NaOH Æ
MW = 40
3
CH3CH2CH2CH2CH2CH2CH2CO
O- Na+
MW = 166.07
3) What is the theoretical yield for the glycerol if 5g of triglyceride react? OR
(same question)
How many grams of glycerol
are produced by reacting
5.0 grams of
4) If 0.8 g of
(CH3CH2CH2CH2CH2CH2CH2COO
CH2)3CH
glycerol
then what is the percent yield for glycerol?
with excess NaOH?
is recovered after the reaction,
+
C3H8O3
MW = 92.11
Saponification
(CH3CH2CH2CH2CH2CH2CH2COO
CH2)3CH
MW = 420.29
+
3 NaOH Æ
MW = 40
3
CH3CH2CH2CH2CH2CH2CH2CO
O- Na+
MW = 166.07
3) What is the theoretical yield for the glycerol if 5g of triglyceride react? OR
(same question)
How many grams of glycerol
are produced by reacting
5.0 grams of
4) If 0.8 g of
(CH3CH2CH2CH2CH2CH2CH2COO
CH2)3CH
glycerol
then what is the percent yield for glycerol?
with excess NaOH?
is recovered after the reaction,
+
C3H8O3
MW = 92.11
pH Practice Problems
Find the pH of a 500.0 mL solution containing 0.185 g of Calcium Hydroxide.
Hints
1. First, find the molarity of the solution.
2. Ask yourself the following:
a. Is Calcium Hydroxide acidic or basic?
b. Is it strong or weak?
3. Write the reaction.
4. Find the pH.
Working Out the Problem
1. Finding the Molarity
Given:
0.185 g Calcium Hydroxide
500.0 mL = 0.5000 L solution
a. What is the equation for molarity?
moles of solute
Molarity=
volume of solution( L)
b. Find the moles of Calcium Hydroxide. Molar Mass = (40.08 g Ca) + (16 g x 2 O) + (1.01 g x 2 H)
Molar Mass = 74.1 g
1 mol Ca(OH)2
0.185 g Ca(OH)2 x
74.1 g Ca(OH)2
0.0024967 mol c. Find the molarity.
0.0024967 mol
= 0.00499 M
Molarity=
0.5000 L
2. Think about Calcium Hydroxide Is Calcium Hydroxide acidic or basic?
Calcium Hydroxide is basic.
Is it strong or weak?
It is a strong base.
3. Write the reaction.
Ca(OH)2 → Ca2+ + 2OH‐
Calcium Hydroxide is a strong base. This means it dissociates completely into calcium and hydroxide ions.
4. Find the pH
a. What are the relevant pH equations?
pH = ‐log([H+])
pOH = ‐log([OH‐])
pH + pOH = 14
b. Ca(OH)2 → Ca2+ + 2OH‐
pOH = ‐log (0.00499 M x 2 OH‐)
pOH = 2.00087
pH = 14 – pOH
pH = 11.999
Does this answer make sense? Why or why not?
Note: Because 0.00499M Ca(OH)2 is a strong base, we assume it dissociates completely. This means the concentration of Calcium ions is 0.00499M. Looking at the reaction, we can see that the concentration of Hydroxide ions is twice that of Calcium (Ca2+ + 2OH‐). That is why we multiply the concentration by 2.
Acids and Bases
A buffer solution is an aqueous solution consisting of a mixture
of…
A weak acid and its conjugate base
A weak base and its conjugate acid
Buffers help keep a solution close to a specific pH
H2PO4- (aq)
Weak Acid
H+ (aq) + HPO42- (aq)
Conjugate Base
Acids and Bases
H2PO4- (aq)
H+ (aq) + HPO42- (aq)
In which direction will the reaction shift if…
1. If H2PO4- is added?
2. If acid is added?
3. If the solution is heated?
ΔH = + 3.6
kJ/mol
Acids and Bases
H2PO4- (aq)
H+ (aq) + HPO42- (aq)
In which direction will the reaction shift if…
1. If H2PO4- is added? Right
1. If acid is added? Left
2. If the solution is heated?Right
ΔH = + 3.6
kJ/mol
Buffers in blood
The carbonic acid/
bicarbonate ion buffer
system is present in our
blood. It is responsible for
maintaining blood pH within
7.35-7.45
Acidosis- blood pH drops
below normal range
Alkalosis- blood pH is higher
than normal range
Buffers in blood
H2CO3 + H2O ↔ HCO3- + H3O+
Which of these acts as a base?
Which acts as an acid?
Considering Le Châtelier’s Principle…
If there is an excess of CO2 dissolved in the blood
forming carbonic acid, in which direction would this
reaction proceed?