Liquid Database 1 10 – Manage Your Collection Of Liquids
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Liquid Database 1 10 – Manage Your Collection Of Liquids
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- Liquid Database 1 10 – Manage Your Collection Of Liquids Can You
- Liquid Database 1 10 – Manage Your Collection Of Liquids Based
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Please note that this page refers to federal requirements. State and local regulations may differ. |
- .Not more than 60 gallons may be Category 1, 2, or 3 liquids. No more than 120 gallons of Category 4 liquids may be stored in a storage cabinet, according to OSHA 29 CFR 1910.106(d)(3)(i). For ease of locating chemicals, many storerooms organize chemicals alphabetically.However, chemical storage based upon an alphabetical arrangement of.
- For 18F it was 1.1 × 10 −6 (4.6 × 10 −7 – 4.6 × 10 −6) representing a potential 2.45 fold increase in cancer risk associated with acetaldehyde with the use of 6 vs. 18 mg/mL e-liquid.
Overview
Transporting Infectious Substances Safely(PHH50-0079-0706). U.S. Department of Transportation. An explanation of the 2006 requirements for transporting infectious substances. |
Department of Transportation (DOT) regulations assign the responsibility to the shipper (e.g., hospital) for properly packaging hazardous materials that are being transported offsite (see shipper's responsibility in 49 CFR 173.22). It is also the responsibility of the shipper that each employee involved with packaging is properly trained (see 49).
Healthcare facilities may ship various types of hazardous materials, including chemicals, compressed gases, etc. The information in this section is limited to packaging of regulated medical waste and infectious substances. For information on packaging and shipping other hazardous materials, consult the applicable sections of HERC and the DOT regulations found under Title 49.
The information presented in this section is specific to federal DOT regulations. Individual states may have somewhat different or additional rules. Check with your state agencies.
Definitions
Packaging and transportation regulations vary, depending on the type of material. The following are important definitions with regard to regulated medical waste and infectious substances.
The term regulated medical waste, is defined differently by many state and federal agencies.Under DOT rules, regulated medical waste (RMW) is a waste or reusable material suspected or known to contain an infectious substance, and is generated in the diagnosis, treatment, immunization, or biomedical research of humans oranimals.
An infectious substance is referred to in DOT regulations as a Division 6.2 material and is defined as a material known or reasonably expected to contain a pathogen. A pathogen is a microorganism (including bacteria, viruses, rickettsiae, parasites, fungi) or other agent, such as a proteinaceous infectious particle (prion) that can cause disease in humans or animals.
An infectious substance must be assigned the identification number UN 2814, UN 2900, or UN 3373, as appropriate:
Category A: An infectious substance in a form capable of causing permanent disability or life-threatening or fatal disease in otherwise healthy humans or animals when exposure to it occurs. A Category A infectious substance must be assigned (based on the known medical history or symptoms of the source patient or animal, endemic local conditions, or professional judgment concerning the individual circumstances of the source human or animal ) one of two identification numbers:
UN 2814 -- infectious substance affecting humans, or humans and animals, or
UN 2900 -- infectious substance which cause disease only in animals.
Category B: An infectious substance that is not in a form generally capable of causing permanent disability or life-threatening or fatal disease in otherwise healthy humans or animals when exposure to it occurs. This includes Category B infectious substances transported for diagnostic or investigational purposes. A Category B infectious substance must be described as Biological substance, Category B and assigned identification number UN 3373.
Regulated Medical Waste Packaging
Although RMW is by definition an infectious substance, it does not fall under the packaging requirements for infectious substances (49 CFR 173.196) because of an exception found in 49 CFR 173.134 (see 173.134(c), exceptions for regulated medical waste).
(a) General provisions. Non-bulk packagings, Large Packagings, and non-specification bulk outer packagings used for the transportation of regulated medical waste or clinical waste or (bio) medical waste must be rigid containers meeting the provisions of subpart B of this part.
(b) Non-bulk packagings. Except as provided in 173.134(c) of this subpart, non-bulk packagings for regulated medical waste or clinical waste or (bio) medical waste must be UN standard packagings conforming to the requirements of Part 178 of this subchapter at the Packing Group II performance level. A non-bulk packaging used as a sharps container must be puncture-resistant for sharps and sharps with residual fluid as demonstrated by conducting the performance tests in Part 178, subpart M, of this subchapter on packagings containing materials representative of the sharps and fluids (such as sterile sharps) intended to be transported in the packagings. Sharps containers must be securely closed to prevent leaks or punctures in conformance with the instructions provided by the packaging manufacturer in accordance with 178.2(c) of this subchapter.
(c) Large Packagings. Large Packagings constructed, tested, and marked in accordance with the requirements of the UN Recommendations (IBR, see 171.7 of this subchapter) and conforming to other requirements of this paragraph (c) may be used for the transportation of regulated medical waste, provided the waste is contained in inner packagings conforming to the requirements of paragraph (e) of this section. Each Large Packaging design must be capable of meeting the vibration test specified in 178.819 of this subchapter. Each Large Packaging is subject to the periodic design requalification requirements for IBCs in 178.801(e) of this subchapter, and to the proof of compliance requirements of 178.801(j) and record retention requirements of 178.801(l) of this subchapter. Inner packagings used for liquids must be rigid.
(1) Authorized packagings. Only the following Large Packagings are authorized for the transportation of liquid or solid regulated medical waste:
(i) Metal: 50A, 50B, or 50N.
(ii) Rigid plastic: 50H.
(2) Additional requirements. Each Large Packaging used to transport liquid regulated medical waste must contain absorbent material in sufficient quantity and appropriate location to absorb the entire amount of liquid present in the event of an unintentional release of contents. Each Large Packaging design intended for the transportation of sharps containers must be puncture resistant and capable of retaining liquids. The design must also be tested and certified as meeting the performance tests specified for intermediate bulk containers intended for the transportation of liquids in subpart O of part 178 of this subchapter.
(d) Non-specification bulk packaging. A wheeled cart (Cart) or bulk outer packaging (BOP) is authorized as an outer packaging for the transportation of regulated medical waste in accordance with the provisions of this paragraph (d).
(1) General requirements. The following requirements apply to the transportation of regulated medical waste in Carts or BOPs:
(i) Regulated medical waste in each Cart or BOP must be contained in nonbulk inner packagings conforming to paragraph (e) of this section.
(ii) Each Cart or BOP must have smooth, non-porous interior surfaces free of cracks, crevices, and other defects that could damage plastic film inner packagings or impede disinfection operations.
(iii) Except as otherwise provided in this paragraph (d), each Cart or BOP must be used exclusively for the transportation of regulated medical waste. Prior to reuse, each Cart or BOP must be disinfected by any means effective for neutralizing the infectious substance the packaging previously contained.
(iv) Untreated concentrated stock cultures of infectious substances containing Category A materials may not be transported in a Cart or BOP.
(v) Division 6.1 toxic waste or Class 7 radioactive waste, with the exception of chemotherapeutic waste, may not be transported in a Cart or BOP.
(vi) Division 6.1 or Class 7 chemotherapeutic waste; untreated concentrated stock cultures of infectious substances containing Category B infectious substances; unabsorbed liquids; and sharps containers may be transported in a Cart or BOP only if packaged in rigid non-bulk packagings conforming to paragraph (a) of this section.
(2) Wheeled cart (Cart). A Cart is authorized as an outer packaging for the transportation of regulated medical waste if it conforms to the following requirements:
Liquid Database 1 10 – Manage Your Collection Of Liquids Can You
(i) Each Cart must consist of a solid, one-piece body with a nominal volume not exceeding 1,655 L (437 gallons).
(ii) Each Cart must be constructed of metal, rigid plastic, or fiberglass fitted with a lid to prevent leakage during transport.
(iii) Each Cart must be capable of meeting the requirements of 178.810 (drop test) at the Packing Group II performance level.
(iv) Inner packagings must be placed into a Cart and restrained in such a manner as to minimize the risk of breakage.
(3) Bulk outer packaging (BOP). A BOP is authorized as an outer packaging for regulated medical waste if it conforms to the following requirements:
(i) Each BOP must be constructed of metal or fiberglass and have a capacity of at least 3.5 cubic meters (123.6 cubic feet) and not more than 45 cubic meters (1,590 cubic feet).
(ii) Each BOP must have bottom and side joints of fully welded or seamless construction and a rigid, weatherproof top to prevent the intrusion of water (e.g., rain or snow).
(iii) Each opening in a BOP must be fitted with a closure to prevent the intrusion of water or the release of any liquid during all loading, unloading, and transportation operations.
(iv) In the upright position, each BOP must be leakproof and able to contain a liquid quantity of at least 300 liters (79.2 gallons) with closures open.
(v) Inner packagings must be placed in a BOP in such a manner as to minimize the risk of breakage. Rigid inner packagings may not be placed in the same BOP with plastic film bag inner packagings unless separated from each other by rigid barriers or dividers to prevent damage to the packagings caused by load shifting during normal conditions of transportation.
(vi) Division 6.1 or Class 7 chemotherapeutic waste, untreated concentrated stock cultures of infectious substances containing Category B infectious substances, unabsorbed liquids, and sharps may be transported in a BOP only if separated and secured as required in paragraph (d)(3)(v) of this section.
(e) Inner packagings authorized for Large Packagings, Carts, and BOPs. After September 30, 2003, inner packagings must be durably marked or tagged with the name and location (city and state) of the offeror, except when the entire contents of the Large Packaging, Cart, or BOP originates at a single location and is delivered to a single location.
(1) Solids. A plastic film bag is authorized as an inner packaging for solid regulated medical waste transported in a Cart, Large Packaging, or BOP. Waste material containing absorbed liquid may be packaged as a solid in a plastic film bag if the bag contains sufficient absorbent material to absorb and retain all liquid during transportation.
(i) The film bag may not exceed a volume of 175 L (46 gallons). The film bag must be marked and certified by its manufacturer as having passed the tests prescribed for tear resistance in ASTM D 1922, Standard Test Method for Propagation Tear Resistance of Plastic Film and Thin Sheeting by Pendulum Method (IBR, 171.7 of this subchapter) and for impact resistance in ASTM D 1709, Standard Test Methods for Impact Resistance of Plastic Film by the Free-Falling Dart Method (IBR, 171.7 of this subchapter). The film bag must meet an impact resistance of 165 grams and a tearing resistance of 480 grams in both the parallel and perpendicular planes with respect to the length of the bag.
(ii) The plastic film bag must be closed with a minimum of entrapped air to prevent leakage in transportation. The bag must be capable of being held in an inverted position with the closed end at the bottom for a period of 5 minutes without leakage.
(iii) When used as an inner packaging for Carts or BOPs, a plastic film bag may not weigh more than 10 kg (22 lbs.) when filled.
(2) Liquids. Liquid regulated medical waste or clinical waste or (bio) medical waste transported in a Large Packaging, Cart, or BOP must be packaged in a rigid inner packaging conforming to the provisions of subpart B of this part. conforming to the provisions of subpart B of this part. Liquid materials are not authorized for transportation in inner packagings having a capacity greater than 19 L (5 gallons).
(3) Sharps. Sharps transported in a Large Packaging, Cart, or BOP must be packaged in a puncture-resistant inner packaging (sharps container). Each sharps container must be securely closed to prevent leaks or punctures in conformance with instructions provided by the packaging manufacturer. Each sharps container exceeding 76 L (20 gallons) in volume must be capable of passing the performance tests in Part 178, subpart M, of this subchapter at the Packing Group II performance level. A sharps container may be reused only if it conforms to the following criteria:
(i) The sharps container is specifically approved and certified by the U.S. Food and Drug Administration as a medical device for reuse.
(ii) The sharps container must be permanently marked for reuse.
(iii) The sharps container must be disinfected prior to reuse by any means effective for the infectious substance the container previously contained.
(iv) The sharps container must have a capacity greater than 7.57 L (2 gallons) and not greater than 151.42 L (40 gallons) in volume. [67 FR 53140, Aug. 14, 2002, as amended at 68 FR 57632, Oct. 6, 2003; 68 FR 75744, Dec. 31, 2003; 71 FR 32261, June 2, 2006; 71 FR 78632, Dec. 29, 2006]
Category B Infectious Substances Packaging.
(a) Category B infectious substances. Except as provided in this paragraph (a), Category B infectious substances are excepted from all other requirements of this subchapter when offered for transportation or transported in accordance with this section. Category B infectious substances offered for transportation or transported under the provisions of this section are subject to the incident reporting requirements in 171.15 and 171.16 of this subchapter and to the requirements in 175.75(b) of this subchapter concerning cargo location. Except as provided in paragraph (a)(9) of this section, a Category B infectious substance meeting the definition of a hazard class other than Division 6.2 must be offered for transportation or transported in accordance with applicable requirements of this subchapter.
(1) A Category B infectious substance must be packaged in a triple packaging consisting of a primary receptacle, a secondary packaging, and a rigid outer packaging.
(2) Primary receptacles must be packed in secondary packaging in such a way that, under normal conditions of transport, they cannot break, be punctured, or leak their contents into the secondary packaging.
(3) Secondary packagings must be secured in rigid outer packagings with suitable cushioning material such that any leakage of the contents will not impair the protective properties of the cushioning material or the outer packaging.
(4) The completed package must be designed, constructed, maintained, filled, its contents limited, and closed so that under conditions normally encountered in transportation, including removal from a pallet or overpack for subsequent handling, there will be no release of hazardous material into the environment. Package effectiveness must not be substantially reduced for minimum and maximum temperatures, changes in humidity and pressure, and shocks, loadings and vibrations normally encountered during transportation. The packaging must be capable of successfully passing the drop tests in 178.609(d) and (h) of this subchapter at a drop height of at least 1.2 meters (3.9 feet). Following the drop tests, there must be no leakage from the primary receptacle, which must remain protected by absorbent material, when required, in the secondary packaging. At least one surface of the outer packaging must have a minimum dimension of 100 mm by 100 mm (3.9 inches).
(5) The following mark must be displayed on the outer packaging on a background of contrasting color. The width of the line must be at least 2 mm (0.08 inches) and the letters and numbers must be at least 6 mm (0.24 inches) high. The size of the mark must be such that no side of the diamond is less than 50 mm (1.97 inches) in length. The proper shipping name Biological substances, Category B must be marked on the outer packaging adjacent to the diamond-shaped mark in letters that are at least 6 mm (0.24 inches) high.
Category A Infectious SubstancesPackaging
(a) Category A infectious substances packaging. A packaging for aDivision 6.2 material that is a Category A infectious substance must meet thetest standards of 178.609 of this subchapter and must be marked inconformance with 178.503(f) of this subchapter. A packaging for a Category Ainfectious substance is a triple packaging consisting of the followingcomponents:
(1) Awatertight primary receptacle.
(2) Awatertight secondary packaging. If multiple fragile primary receptacles areplaced in a single secondary packaging, they must be either wrappedindividually or separated to prevent contact between them.
(3) Arigid outer packaging of adequate strength for its capacity, mass and intendeduse. The outer packaging must measure not less than 100 mm (3.9 inches) at itssmallest overall external dimension.
(4) For aliquid infectious substance, an absorbent material placed between the primaryreceptacle and the secondary packaging. The absorbent material must besufficient to absorb the entire contents of all primary receptacles.
(5) Anitemized list of contents enclosed between the secondary packaging and theouter packaging.
(6) Theprimary receptacle or secondary packaging used for infectious substances mustbe capable of withstanding, without leakage, an internal pressure producing apressure differential of not less than 95 kPa (0.95 bar, 14 psi).
(7) Theprimary receptacle or secondary packaging used for infectious substances mustbe capable of withstanding without leakage temperatures in the range of
(b) Additional requirements for packaging Category Ainfectious substances. Category A infectious substances must be packaged accordingto the following requirements, depending on the physical state and othercharacteristics of the material.
(1) Infectious substances shipped atambient temperatures or higher. Primary receptacles must be made of glass, metal, orplastic. Positive means of ensuring a leakproof seal must be provided, such asheat seal, skirted stopper, or metal crimp seal. If screw caps are used, they mustbe secured by positive means, such as with adhesive tape, paraffin sealingtape, or manufactured locking closure. Lyophilized substances may also betransported in primary receptacles that are flame-sealed with glass ampoules orrubber-stoppered glass vials fitted with metal seals.
(2) Infectious substances shippedrefrigerated or frozen (ice, pre-frozen packs, dry ice). Ice, dry ice, or otherrefrigerant must be placed around the secondary packagings or in an overpack withone or more complete packages marked in accordance with 178.503 of thissubchapter. Interior supports must be provided to secure the secondary packagingsin the original position after the ice or dry ice has dissipated. If ice isused, the outer packaging or overpack must be leakproof. If dry ice is used,the outer packaging or overpack must permit the release of carbon dioxide gasand otherwise meet the provisions in 173.217. The primary receptacle and thesecondary packaging must maintain their integrity at the temperature of therefrigerant used, as well as the temperatures and pressures of transport byaircraft to which they could be subjected if refrigeration were lost.
(3) Infectious substances shipped inliquid nitrogen. The primaryreceptacle and the secondary packaging must maintain their integrity at thetemperature of the liquid nitrogen as well as the temperatures and pressures oftransport by aircraft to which they could be subjected if refrigeration were lost.Refrigerated liquid nitrogen packagings must be metal vacuum insulated vesselsor flasks vented to the atmosphere to prevent any increase in pressure withinthe packaging. The use of safety relief valves, check valves, frangible discs,or similar devices in the vent lines is prohibited. Fill and discharge openingsmust be protected against the entry of foreign materials that might cause anincrease in the internal pressure. The package orientation markings specifiedin 172.312(a) of this subchapter must be marked on the packaging. Thepackaging must be designed to prevent the release of any refrigerated liquidnitrogen irrespective of the packaging orientation.
(c) Live animals maynot be used to transport infectious substances unless such substances cannot besent by any other means. An animal containing or contaminated with aninfectious substance must be transported under terms and conditions approved bythe Associate Administrator for Hazardous Materials Safety.
(d) Body parts, organs or whole bodies meeting the definition of Division 6.2 material must bepackaged as follows:
(1) InDivision 6.2 packaging, as specified in paragraphs (a) and (b) of this section;or
(2) Inpackaging meeting the requirements of 173.197.
Training
49CFR 172.704
A hazmat employer must train all hazmat employees in general awareness training, function-specific regulatory training, and safety training. For example, healthcare professionals need training to properly use any packaging authorized for the transportation of infectious substances.
Security
49 CFR 172.800, 49 CFR 172.802 and 49CFR 172.804
DOT requires anyone that transports select agents and toxins regulated by 9 CFR 121 to develop and implement security plans under 49 CFR 172. DOT has developed a security template that can be used to identify points in the transportation process where security procedures should be enhanced.
Reporting and Recordkeeping
49 CFR 171.51, 49 CFR 172.201, and 49 CFR 177.817
For all hazardous materials other than hazardous waste, the shipping paper copy must be retained by the shipper for 2 years after the material is accepted by the initial carrier. Except for hazardous waste, carriers must retain a copy of the shipping paper for at least 1 year after accepting the hazardous material.
More Resources
Transporting Infectious Substances Safely (PHH50-0079-0706). U.S. Department of Transportation. An explanation of the new requirements for transporting infectious substances.
Liquid
- Behaviour of pure liquids
- Solutions and solubilities
- Classes of solutions
- Properties of solutions
- Composition ratios
- Equilibrium properties
- Colligative properties
- Transport properties in solutions
- Thermodynamics and intermolecular forces in solutions
- Molecular structure and charge distribution
- Effects of chemical interactions
- Theories of solutions
- Regular and athermal solutions
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John M. PrausnitzSee All ContributorsProfessor of Chemical Engineering, University of California, Berkeley. Author of Molecular Thermodynamics of Fluid-Phase Equilibria.
Alternative Title: liquid state
Liquid, in physics, one of the three principal states of matter, intermediate between gas and crystalline solid.
Physical properties of liquids
The most obvious physical properties of a liquid are its retention of volume and its conformation to the shape of its container. When a liquid substance is poured into a vessel, it takes the shape of the vessel, and, as long as the substance stays in the liquid state, it will remain inside the vessel. Furthermore, when a liquid is poured from one vessel to another, it retains its volume (as long as there is no vaporization or change in temperature) but not its shape. These properties serve as convenient criteria for distinguishing the liquid state from the solid and gaseous states. Gases, for example, expand to fill their container so that the volume they occupy is the same as that of the container. Solids retain both their shape and volume when moved from one container to another.
Liquids may be divided into two general categories: pure liquids and liquid mixtures. On Earth, water is the most abundant liquid, although much of the water with which organisms come into contact is not in pure form but is a mixture in which various substances are dissolved. Such mixtures include those fluids essential to life—blood, for example—beverages, and seawater. Seawater is a liquid mixture in which a variety of salts have been dissolved in water. Even though in pure form these salts are solids, in oceans they are part of the liquid phase. Thus, liquid mixtures contain substances that in their pure form may themselves be liquids, solids, or even gases.
The liquid state sometimes is described simply as the state that occurs between the solid and gaseous states, and for simple molecules this distinction is unambiguous. However, clear distinction between the liquid, gaseous, and solid states holds only for those substances whose molecules are composed of a small number of atoms. When the number exceeds about 20, the liquid may often be cooled below the true melting point to form a glass, which has many of the mechanical properties of a solid but lacks crystalline order. If the number of atoms in the molecule exceeds about 100–200, the classification into solid, liquid, and gas ceases to be useful. At low temperatures such substances are usually glasses or amorphous solids, and their rigidity falls with increasing temperature—i.e., they do not have fixed melting points; some may, however, form true liquids. With these large molecules, the gaseous state is not attainable, because they decompose chemically before the temperature is high enough for the liquid to evaporate. Synthetic and natural high polymers (e.g., nylon and rubber) behave in this way.
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If the molecules are large, rigid, and either roughly planar or linear, as in cholesteryl acetate or p-azoxyanisole, the solid may melt to an anisotropic liquid (i.e., one that is not uniform in all directions) in which the molecules are free to move about but have great difficulty in rotating. Such a state is called a liquid crystal, and the anisotropy produces changes of the refractive index (a measure of the change in direction of light when it passes from one medium into another) with the direction of the incident light and hence leads to unusual optical effects. Liquid crystals have found widespread applications in temperature-sensing devices and in displays for watches and calculators. However, no inorganic compounds and only about 5 percent of the known organic compounds form liquid crystals. The theory of normal liquids is, therefore, predominantly the theory of the behaviour of substances consisting of simple molecules.
Liquid Database 1 10 – Manage Your Collection Of Liquids Included
A liquid lacks both the strong spatial order of a solid, though it has the high density of solids, and the absence of order of a gas that results from the low density of gases—i.e., gas molecules are relatively free of each other’s influence. The combination of high density and of partial order in liquids has led to difficulties in developing quantitatively acceptable theories of liquids. Understanding of the liquid state, as of all states of matter, came with the kinetic molecular theory, which stated that matter consisted of particles in constant motion and that this motion was the manifestation of thermal energy. The greater the thermal energy of the particle, the faster it moved.
Transitions between states of matter
In very general terms, the particles that constitute matter include molecules, atoms, ions, and electrons. In a gas these particles are far enough from one another and are moving fast enough to escape each other’s influence, which may be of various kinds—such as attraction or repulsion due to electrical charges and specific forces of attraction that involve the electrons orbiting around atomic nuclei. The motion of particles is in a straight line, and the collisions that result occur with no loss of energy, although an exchange of energies may result between colliding particles. When a gas is cooled, its particles move more slowly, and those slow enough to linger in each other’s vicinity will coalesce, because a force of attraction will overcome their lowered kinetic energy and, by definition, thermal energy. Each particle, when it joins others in the liquid state, gives up a measure of heat called the latent heat of liquefaction, but each continues to move at the same speed within the liquid as long as the temperature remains at the condensation point. The distances that the particles can travel in a liquid without colliding are on the order of molecular diameters. As the liquid is cooled, the particles move more slowly still, until at the freezing temperature the attractive energy produces so high a density that the liquid freezes into the solid state. They continue to vibrate, however, at the same speed as long as the temperature remains at the freezing point, and their latent heat of fusion is released in the freezing process. Heating a solid provides the particles with the heat of fusion necessary to allow them to escape one another’s influence enough to move about in the liquid state. Further heating provides the liquid particles with their heat of evaporation, which enables them to escape one another completely and enter the vapour, or gaseous, state.
This starkly simplified view of the states of matter ignores many complicating factors, the most important being the fact that no two particles need be moving at the same speed in a gas, liquid, or solid and the related fact that even in a solid some particles may have acquired the energy necessary to exist as gas particles, while even in a gas some particles may be practically motionless for a brief time. It is the average kinetic energy of the particles that must be considered, together with the fact that the motion is random. At the interface between liquid and gas and between liquid and solid, an exchange of particles is always taking place: slow gas molecules condensing at the liquid surface and fast liquid molecules escaping into the gas. An equilibrium state is reached in any closed system, so that the number of exchanges in either direction is the same. Because the kinetic energy of particles in the liquid state can be defined only in statistical terms (i.e., every possible value can be found), discussion of the liquid (as well as the gaseous) state at the molecular level involves formulations in terms of probability functions.
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Liquid Database 1 10 – Manage Your Collection Of Liquids