Hallucinogens – mostly naturally
occurring substances that can change
normal thought processes,
perceptions, and moods.
Stimulants – act on the nervous
system to make the user feel better
and increase his/her energy/alertness.
Narcotics/analgesics – substances
affecting the central nervous system
to relieve pain.
Depressants – a drug that reduces
excitability and calms a person.
• Toxicology – the study of the adverse
effects of chemicals or physical agents
on living organisms.
The chemical form of the substance
(pure arsenic versus arsenic trioxide).
Method of entry (oral versus
Condition of victim (weight, age,
Time period of exposure
• chronic exposure – continuing
exposure over long periods of time
• acute exposure – large dosage at one
Presence of other chemicals.
• synergism – combined effect of
substances that exceeds the sum of
their individual effects.
• antagonism – combined effect of
substances that decrease their
• Chelating agent – an organic
compound that combines with a metal
to form a ring compound.
• Alcohol is the most abused depressant in the
• The chemical name for alcohol is ethanol or
• Ethanol, like all alcohols, is toxic.
• Ethanol effects the central nervous system.
• Alcohol circulates in the blood stream
immediately after consumption.
Alcohol and the Law
• The law is concerned with the level of
blood alcohol content (BAC).
• BAC is expressed as a percent weight per
• Federal and Kansas BAC limits are both
• This means that there is 0.08 grams of pure
alcohol for every 100 mL of blood.
DUI – driving under the influence
DWI – driving while intoxicated
OUI – operating under the influence
OWI – operating while intoxicated
MIP – minor in possession
• The average person removes 0.015 percent
• About 5% of ethanol leaves the body through
respiration, perspiration, and urine.
• About 90% of alcohol is chemically
processed (metabolized) by the liver.
• It is changed first to acetaldehyde (a poison).
• Then it is changed to acetic acid and finally to
carbon dioxide and water.
HCH3COO →CO2 + H2O
Alcohol & the Liver
0.071 (volum edcon
sum ed, oz) (%alcohol)
0.085 (volum edcon
sum ed, oz) (%alcohol)
0.02 divided attention, slowed reaction time
0.04 Eye movement control
0.08 Concentrated attention, speed control
• Henry’s Law - At a constant temperature,
the amount of a given gas dissolved in a
given type and volume of liquid is directly
proportional to the partial pressure of that
gas in equilibrium with that liquid.
• According to Henry’s Law the
concentration of alcohol in the breath is
proportional to the concentration of alcohol
in the blood.
The Chemistry of Breathalyzers
• An orange dichromate ion is reduced to
a green chromium (III) ion.