Bio Chem Flashcards
Does a persistent chemical have a high boiling point or low boiling point
High boiling point
What is meant by LD50
LD50 is the amount of substance administered by a defined route of entry over a specific period that is expected to cause the death of 50% of a defined animal population.
What Is ED50
50% probability of effect.
Why are solids rarely used in chemical weapons?
Solids can be used but these are difficult to disseminate.
What’s vapour pressure depend on?
Vapour pressure depends on temperature.
Will a substance with a higher vapour pressure evaporate more or less quickly than one with low vapour pressure?
A substance with a high vapour pressure will evaporate more quickly than one with a low vapour pressure.
What is the calculation of max concentration?
(1 x 10^6 x vapour pressure (torr))/760 in ppm
What is the standard vapour pressure of mustard gas at 20 degrees C?
0.072 torr
What is the maximum concentration of mustard gas?
96 ppm (610mg/m^3)
What is vapour density?
Vapour density is the ratio of the molecular mass of the substance to the average molecular mass of air.
Non persistent agents are? (3 things)
Volatile, low boiling point liquid (or gases), with high vapour pressures. E.g. chlorine, phosgene
Persistent agents are? (3 things)
Non-volatile, high boiling point liquids (or solids), with low vapour pressures.
What are non persistent chemicals used for?
Produce a toxic cloud of vapour which is often heavier than air, thus capable of penetrating foxholes and bunkers.
Persistent chemical agents are used for?
These are usually liquids which are used to produced a chemical rain or spray to contaminate troops, ground or equipment. Many organic liquids are able to penetrate the skin.
What is the arbitrary between persistent and non persistent?
The vapour pressure.
Does the persistence of the chemical agent increase as the temperature falls?
Yes.
Why can mixtures of gases be denser than air?
Because the molecules are heavier, because they are colder or both can apply.
What happens to the liquid when it’s goes from vapour pressure to atmospheric pressure (in an open system)?
The liquid will boil. The liquid will not be a liquid above its boiling point unless it is contained under pressure. Liquids will start to evaporate below the boiling point, how much depends on the surface area.
What is a cold cloud?
Any vapour held under pressure or chemicals that evaporate quickly will form a cold cloud. Once the pressure is released from a gas that has been liquified by pressure, it has to evaporate, or some of it evaporates and some of it is cooled below its boiling point.
what happens when a cold cloud is formed?
A cloud is produced which is colder and denser than air.
How soluble is mustard in water?
Sparingly soluble (0.8gLitre^-1)
What is more soluble, nerve agents or mustard?
Nerve agents are more soluble and may hydrolyse.
When hydrogen cyanide dissolves in water can you ingest it?
Hydrogen cyanide is soluble but the solution is still poisonous if ingested.
Can phosgene be destoryed in water?
Phosgene is soluble and is rapidly destroyed in water.
After Lewisites hydrolyse in humid air and are destoryed, what do they leave behind?
It leaves arsenic - which is toxic.
What happens when the surface tension of a liquid is lower than the surface energy of the surface on which it lands?
It will spread.
What do the new Mk IVa suits been treated to stop?
Mk IVa have been treated to prevent agent spreading.
What is the surface tension of bare metal?
100 mN m^-1
What is the surface tension of water?
72 mN m^-1
What is the surface tension of Mustard?
42 Nm m^-1
If the surface tension of a liquid is lower than the surface tension of a material what happens?
It will spread.
How are Vapours removed from the air?
By physical adsorption.
What does the the uptake of a gas by the adsorption depend upon?
To a great extent it depends upon its boiling point.
If a substance has a low boiling point what else will be low?
It will have a low inter-molecular forces. These are the same forces which hold it to the surface of a solid.
What can Adsorption be viewed as?
Adsorption can be viewed as turning a vapour back to a liqiuid and is most effective at a given concentration for high boiling point liquids.
What happens when Charcoal capacity is reached for high boiling point substances?
Charcoal wil have capacity for high boiling point subtances =until a concentraion is reached where all the pores are full.
What do respirators have in them?
Chemicals to remove vapours below the boiling point of 65 degrees C.
What is the boiling point of Hydrogen Cyanide?
26 Degrees C
What is the boiling point of Phosgene?
8 Degrees C
What is the boiling point of Arsine?
-55 Degrees C
What is military activated carbon impregnated with?
Copper, Copper oxide, Silver, Chromium hydrolyses cyanogen, and Triethylaminediamine.
Can chemical agents permeate with rubbers and plastics?
Some rubbber and plastics can be permeated by Chemical Agents.
If a plastic is permeated how can you tell?
The polymer will often swell or soften, eventually agents vapour will pass through the polymer and come out the other side.
What will the mpt and bpt of a chemcial determine?
How it will be dispersed, how long it will remain a liquid hazard when dispersed, the maximum vapour concentration that can reach in air at different temperature as it evaporates, and the design of respirators and protective clothiung provided to protect against it.
The surface tension of a chemical agent will determine?
How it interacts with equipment and clothing.
The relationship between the liquid properties of the chemical agent and polymers will determine?
If the agent can penetrate the polymer to prolong a vapour hazard, and if it can pass through the polymer barrier.
Name me some good old fashion poisons!
Ricin, arsenic, chlorine, mercury, nicotine, chloroform, phosgene, nerve gases, cyanide, etc..
What is dose?
The amount of substance that comes into contact with a living organism. (mg/kg)
How is concentration if exposed from the air measured in?
mg m^-3
How is concentration x time measured in?
mg min m^-3
what is ED50?
50% probablilty of effect.
What is LD50?
50% probability of lethality.
What is ID50?
50% probability of incapacity.
What is Haber rule?
Haber Rule = Concentration x time
What is LCt
Leathal exposure. Measure in mg min m^-3
What is ICt
Incapacitating exposure. Measure in mg min m^-3
What are the 5 main routes of entry?
Gastrointestinal tract - ingestion
Respiratory - inhalation
Percutaneous - Skin (demal)
Subcutaneous - under the skin
Parenteral - Other routes eg injection, intravenous etc
What Physiological systems that can be affected?
Respiratory, integumentary (skin), Cardiovascular, lymphatic and immune, and Nervous
What can pass through the membrane lining of the lungs?
Oxygen, Nitrogen, Water.
How are large particals removed from the lungs?
They make contact with the bronchiole level and be removed by the ciliated epithelium.
What do very small particle s penetrate in the lung including gases and vapours?
Alveoli.