Physical Properties
The following physical properties are shown on chemical datasheets, when available:
- Chemical FormulaChemical Formula
The molecular formula describing the exact number and type of atoms in a single molecule of a chemical.
- Flash PointFlash Point
The lowest temperature at which a liquid gives off enough vapor to be ignited at its surface. See topic on Could it burn or explode?
- Lower Explosive Limit (LEL)Lower Explosive Limit (LEL)
Also called lower flammability limit. Lowest concentration of a flammable vapor  in air at which explosion or combustion can occur. See topic on Could it burn or explode?
- Upper Explosive Limit (UEL)Upper Explosive Limit (UEL)
Also called upper flammability limit. Highest concentration of a flammable vapor in air at which explosion or combustion can occur. See topic on Could it burn or explode?
- Autoignition TemperatureAutoignition Temperature
Minimum temperature at which a chemical ignites when no ignition source (such as a spark or flame) is present. See topic on Could it burn or explode?
- Melting PointMelting Point
Also called freezing point . The temperature at which the solid and liquid phases of a substance exist in equilibrium. Depends on chemical composition and applied pressure.
- Vapor PressureVapor Pressure
A measure of a substance's tendency to evaporate; liquids with higher vapor pressures evaporate faster. See topic on Is its vapor dangerous?
- Vapor Density (Relative to Air)Vapor Density (Relative to Air)
The ratio of the density of a gas to the density of air at the same temperature. A gas with a vapor density greater than 1.0 is heavier than air and will sink in the atmosphere. Starting with CAMEO 365betÓéÀÖ 3.0.0, short phrases have been added to tell you if the chemical gas will likely sink or rise in air.
Note:Â The vapor density comparisons are only valid when the gas escaping is at the same temperature as the surrounding air itself. If the chemical is escaping from a container where it was pressurized or refrigerated, it may first escape and behave as a heavy gas and sink in the air (even if it has a vapor density value less than 1).
- Specific GravitySpecific Gravity
The ratio of the density of a chemical to the density of water at the same temperature. A chemical with a specific gravity greater than 1.0 will sink rather than float in water. Starting with CAMEO 365betÓéÀÖ 3.0.0, short phrases have been added to tell you if the chemical will likely sink or float in water.
Note: The specific gravity comparisons are for fresh water (density 1.0 g/mL). If your spill is in salt water (density about 1.027 g/mL), you need to adjust the point of comparison. There are some chemicals that will sink in fresh water and float in salt water. See topic on Would it float or sink?
- Boiling PointBoiling Point
The maximum temperature at which the liquid phase of a substance exists in equilibrium with its vapor  phase. Above the boiling point, a liquid vaporizes completely. At its boiling point, the vapor pressure of a liquid is equal to the atmospheric pressure on it.
- Molecular WeightMolecular Weight
The sum of the weights of all the atoms in a molecule .
- Water SolubilityWater Solubility
The highest amount of a particular material that can be mixed in water is its water solubility . In CAMEO 365betÓéÀÖ, the water solubility ranges shown on chemical datasheets are as follows:
- Water insoluble: <0.1% (<1 mg/mL)
- Slightly water soluble: 0.1%-1% (1-10 mg/mL)
- Water soluble: >1% (>10 mg/mL)
See topic on Would it dissolve in water?
- Ionization Energy/PotentialIonization Energy/Potential
The energy required to 'ionize' or remove an electron from an atom. The ions can be measured by a photoionization detector (PID), which measures the relative concentration of ionized compounds. The ionization energy identifies the minimum energy level of the PID lamp that is required to ionize an atom or molecule. Ionization energy may also be known as ionization potential.
- Levels of Concern (LOCs), such as IDLH, AEGLs, ERPGs, and PACsLevels of Concern (LOCs), such as IDLH, AEGLs, ERPGs, and PACs
An LOC Â tells you what level of exposure to a chemical could hurt you or other people. See a guide to LOCs.
Here is an example of the Physical Properties portion of the chlorine datasheet: