Vocab Flashcards
How do mmgh, atm, and psi relate?
They’re all units of measure for gases. 760mmgh = 1 ATM = 14.7psi
What is Vapor Density?
The weight of a vapor or gas compared to the weight of an equal volume of air; an expression of the density of the vapor or gas. Materials lighter than air have vapor densities less than 1.0 (example: acetylene, methane, hydrogen).
What is Specific Gravity?
Specific gravity, more formally known as relative density, is a measure of the density of a substance in comparison to the density of water. AKA RGasD
What is Vapor Pressure
The vapor pressure of a liquid is the point at which equilibrium pressure is reached, in a closed container, between molecules leaving the liquid and going into the gaseous phase and molecules leaving the gaseous phase and entering the liquid phase.
Atomic weight of air
29 g/mol
What is a flammable liquid?
A liquid with a flashpoint of less than 100F for IFSTA. Less than 141F for VDEM
What is a combustible liquid?
A liquid with a flashpoint above 100F but below 200F
What is a cryogenic?
-130F, high expansion ratio and oxygen displacement
Define flash point
When a LIQUID gives off enough vapor above the surface of the liquid to create an ignitable mixture in air that will sustain combustion. Gas does not have a flashpoint.
What is IP?
Ionization potential. This is the amount of energy it takes to remove an electron from an atom.
Define expansion ratio
How many gallons of gas a liquid will make per gallon
Define polymerization
When monomers react with themselves to create a polymer (3D product). Usually stopped by an inhibitor. When polymerization happens there is an exothermic reaction that releases heat.
What is sublimation?
When a substance skips a phase and changes directly from a solid to a gas or vice versa.
Define auto refrigeration
When an unintentional and/or uncontrolled phase change of a hydrocarbon from a liquid state to a vapor occurs resulting in a very rapid reduction in the temperature of the local equipment or piping.
What is an endothermic reaction?
A reaction that absorbs heat. Ice absorbs the heat around it
What is an exothermic reaction?
A reaction that gives off heat. Fire, polymerization
Define SADT
Self Accelerating Decomposition Temperature. The temperature above which an unstable chemical will decompose unimpeded regardless of ambient temperature.
Volatility
Volatility describes the ease with which a liquid can pass into the vapor state. The higher a material’s volatility, the greater its evaporation rate. Vapor pressure is a measure of a liquid’s propensity to evaporate. Thus, the higher a liquid’s vapor pressure, the more volatile it is.