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Alcohols and Depressants

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Sophie Robert

on 26 October 2013

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Transcript of Alcohols and Depressants

D4: Depressants
What are they?
Depressants are drugs that depress the central nervous system by interfering with the transmission of nerve impulses in the nerve cells.

By changing the concentration of neurotransmitters, brain activity and breathing rate are decreased.

What are the side effects?
Effects by Dosage:
Low doses
- increase feeling of calm, drowsiness, relief of anxiety/tension, reduction of inhibition, slower mental activity.

Moderate to higher doses
- slurred speech, faltering movement, altered perception, and sleep.

High doses
- decreases breathing and heart rates, sleep, loss of consciousness, coma, and death.
D.4.1. Types of Depressants
D.4.2 Social and Psychological Effects of Ethanol Abuse
D.4.3 Methods of Ethanol Detection in Breath, Blood and Urine
Ethanol establishes an equilibrium between being dissolved in the blood and being in exhaled breath.
C2H5OH(aq) in blood <--> C2H5OH(g)
The equilibrium constant, Kc for this reaction does not change with temperature so if you measure the concentration of ethanol in the breath you can determine the concentration in the blood.

- seven member ring fused to a benzene ring with four main substitute groups


Diazepam (valium
- seven member ring containing 2 N atoms fused to a benzene ring

- one of the C atoms on the benzene ring has a (Cl-) functional group on it

- on the 7 member nitrogen containing ring, one carbon atom is attached to a methyl (CH3-) group one carbonyl (C=O) functional group and one benzene ring
- prescribed by a doctor
- prescribed by a doctor
Self Medicating Depressants
- alcohol (beer,
wine, etc.) and narcotics (heroin, marijuana).
Opiates and Opiums

Roadside Breathalyser
For analysing alcohol in breath
80mg ethanol/100ml blood
What is happening ?
The person blows into the photocell device containing orange dichromate (VI) crystals, K2Cr2O7 (orange).

The photo cell measures the degree to which the colour has changed to measure the degree of change in ethanol.
The higher the [ethanol], the more K2Cr2O7 is reduced and the greener the crystals become.
If ethanol is present, the crystals are reduced to green Chromium (III) ions.
Ethanol is reduced to ethanoic acid.
Used to measure alcohol in breath, more accurate than a breathalyser, found in police station.
Simple Version:
How does it work?
Person breathes into the infrared spectrometer

The absorption of infrared radiation (IR) of the specific wavelength of the O--H bond in the ethanol produces a characteristic peak in the spectrum.

The amount of absorption depends on the concentration of alcohol in the breath.

Ethanol is compared with air or another reference source to determine whether the concentration is over the allowed amount.
More in depth:
Because bonds vibrate (stretch and bend), bond angles and lengths between them are always changing.
For this reason, atoms in a molecule are always moving.
The bond vibrations produce an electric field with the same wavelength as IR radiation.
As each molecule has a unique set of bonds, each molecule will produce its own IR spectrum (a fingerprint).
The homologous series of alcohols produce a signature IR spectrum as they each has a hydroxyl functional group (C-O-H) that is unique to them.
Not accurate to be used in court to convict someone.
They all have a O-H bond and the C-O stretching vibrations (which appear in the region 3500-3200 cm-1) are a very intense, broad band.

The O-H stretch shows up in the region 1260 - 1050 cm-1. The size of the peak is then converted into an ethanol concentration.

D.4.5 Identify other commonly used depressants and describe their structure
- seven member ring fused to a benzene ring with four main substitute groups


Nitrazepam (sleeping pills
- seven member ring fused to a benzene ring

- one of the C atoms on the benzene ring has a nitro (NO2) functional group on it

- on the 7 member nitrogen containing ring, one nitrogen atom is attached to a methyl (CH3-) group, one carbon is attached to a carbonyl (C=O) functional group and another carbon a benzene ring
D.4.5 Identify other commonly used depressants and describe their structure
D.4.4 Describe the synergistic effects of ethanol with other drugs
Alcohol can interact and augment the activity of other drugs when taken at the same time as it depresses the central nervous system itself. This is called
Prozac (fluoxetine hydrochloride)

- two benzene rings, one with CF3 group attached to it
- joined by an ether group (C-O-C), a carbontrifluoride (CF3) and secondary amine (-N-)

D.4.5 Identify other commonly used depressants and describe their structure
Examples of synergistic effects include:
aspirin with alcohol = increased bleeding in stomach lining
alcohol with other depressants such as barbiturate such as sleeping pills induces heavy sedation, even coma
with tobacco can increase incidence of cancers, in intestines and liver
with drugs can interfere with the metabolism of the liver, which can cause greater and more prolonged drug effects
Ethanol Analysis in Blood and Urine
Gas-liquid chromatography
is the most established method of ethanol analysis and must be done in a lab.

Blood or urine is vapourised and injected into a stream of an inert gas (
mobile phase
) over the surface of a non-volatile liquid (
stationary phase

The components of the vapour, including ethanol gas, move at different rates depending on their boiling points and relative solubility in the two phases.

As a result, each leaves the column holding the liquid phase after a specific interval of time known as its
retention time
Effects by Type:
(alcohol and valium) reduce nervous tension without inducing sleep in moderate doses
(barbiturates) sooth distress without inducing sleep in moderate doses
(choral hydrate) induces sleep
So a peak at the retention time corresponding to ethanol can be used to confirm its presence in the vapour. The area under the peak is a measure of ethanol concentration relative to a known standard in the mixture such as propan-1-ol. The method allows for an accurate assessment of ethanol levels.
Works Cited:
-"Alcoholism," Microsoft® Encarta® Online Encyclopedia 2009
-Brown, Catra and Mike Ford. Standard Level Chemistry. Heinemann Baccalaureate, 2008.
-Derry, Lanna, Maria Connor and Carol Jordan. Chemistry for use for the IB Diploma Standard level. Melbourne: Pearson Education, 2008.
- IB Chemistry Data Booklet
Neuss, Geoffrey. IB Diploma Programme Chemistry Course Companion. Oxford: Oxford University Press, 2007.
—. IB Study Guides, Chemistry for the IB Diploma. Oxford: Oxford University Press, 2007.
Organisation, International Baccalaureate. Online Curriculum Centre. <http://occ.ibo.org/ibis/occ/guest/home.cfm>.
—. "Chemistry Data Booklet." International Baccalaureate Organisation, March 2007.
—. "Chemistry Guide." International Baccalaureate Organisation, March 2007.
—. "IB Chemistry Examination Papers ." Cardiff: International Baccalaureate Organisation, 1999-2008.
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