Matter States and Properties PDF

**Matter exists in three primary forms.** **Knowing the state of matter helps responders determine control zones and evacuation distances.** - **Solids** - **Are the least mobile** - **Gases** - **Have the greatest mobility** - **Liquids** - **Are less mobile than gase...

**Matter exists in three primary forms.** **Knowing the state of matter helps responders determine control zones and evacuation distances.** - **Solids** - **Are the least mobile** - **Gases** - **Have the greatest mobility** - **Liquids** - **Are less mobile than gases** - **Will flow from their container and follow the law of gravity** **The physical state of a material is determined at normal temperatures and pressures.** - **Assume** - **Temperatures between 68°F and 77°F (20°C and 25°C)** - **Pressure to be atmospheric pressure (14.7 psi)** **Some matter can exist in different states.** - **Water is liquid in its natural state** - **Can become a solid (ice) below 32°F (0°C)** - **Can become a gas (steam) above 212°F (100°C)** **The physical state of a material is determined at normal temperatures and pressures.** - **Temperature is the determining factor, as is the case with many materials that change state** - **Pressure is sometimes used to cause a change in state, as is the case with liquefied compressed gases** - **Both temperature and pressure are used to transform gases into cryogenic liquids** **Matter can exist in multiple states within the same container at a hazardous materials incident.** - **A liquefied gas vaporizes as it escapes a breached container** - **In these instances, the product exists as** - **Liquid inside the container and as** - **Gas outside the container** - **Within a container, there may be** - **Liquid space at the bottom and** - **Vapor space at the top** - **Fire impinging on the vapor space stresses a container far more so than fire impinging on the liquid space because the liquid helps absorb the heat whereas vapors do not** **Some items act like a gas and can be very mobile.** - **Vapor** - **Gaseous state of a material that may normally be a solid or a liquid** - **Aerosol** - **Microscopic particles that may be a solid or a liquid** - **Dust** - **Airborne solid particles 0.1-50 microns in diameter** - **Particles less than 50 microns cannot be seen without a microscope** - **Mist** - **Aerosol of liquid particles suspended in air** - **Fog** - **Visible aerosol of a liquid formed by condensation** **The state of matter is largely dependent on the temperature of a substance.** - **State may change if the temperature changes** - **For example, a solid may change to a liquid if the temperature increases** - **If a material is located outdoors** - **Temperature and weather can have a profound effect on a material's state of matter** **NOTE** - **Weather factors such as atmospheric pressure, relative humidity, dew points, and temperature can affect the behavior and chemical and physical properties of materials.** **Physical properties of a state of matter are a factor of intermolecular attraction.** - **Molecules of a gas** - **Weak interaction** - **Molecules of a solid** - **Strong interaction** Know the characteristics of a solid. - Will have a specific mass and volume - Will take on a specific shape - The least mobile of the three states of matter A solid may have the ability to become airborne. - In its natural state, and based on its dimensions, a piece of wood may be able to move only in strong winds - Reducing the piece of wood to sawdust changes the surface area, and a light breeze or even natural air currents may cause the material to become airborne - Dust is even more prone to movement by natural air currents Liquids often present unique challenges from a response standpoint. - May be more difficult to contain than a solid - Its vapor has the characteristics of a gas which can increase its mobility and, consequently, the challenges that technicians will face when dealing with the material Molecules of a liquid may flow freely - Will have specific mass and volume like a solid - Will not have a definitive shape - Will take on the shape of its container because of the loose molecular attraction Hazardous materials in gaseous form are typically the most challenging to\ control. - Gases will have a specific mass but will not have a specific volume or shape - Will expand to fill any given volume - Gas molecules move with a great deal of energy - Are the least dense of the three states of matter and have the ability to compress - Cooling of gases can sometimes cause them to take liquid form Emergency responders will typically be at the greatest risk when dealing\ with a gas. - Many hazmat related contaminations and exposures are due to the inhalation of vapors or gases - Gaseous material will have many variables and hazards - May or may not have an odor - May be colorless and/or tasteless - May be toxic, corrosive, or flammable - May be under extremely high pressure in excess of 15,000 psi (103 500 kPa) - May be extremely cold upon release - May have a large expansion ratio if liquefied Gases are the only state of matter that can be compressed tightly or expanded to fill a large space. - Hazmat incidents involving gases typically include products contained under pressure - It is important to understand how gases behave when under pressure Atmospheres are normally used as a standard unit of pressure in the U.S. - In the International System of Units (SI), units of pressure are typically measured in Pascals (Pa) - One atmosphere (atm) is equal to 101.325 Pa - One atm is defined as 760 millimeters of mercury (mmHg) and is the pressure normally found at sea level - Less commonly used units of pressure are bar and torr Gases have a vapor pressure greater than 760 mm Hg at 68°F. Hazardous materials technicians may encounter gases in different forms or states. - Compressed gases are compounds and mixtures in a gaseous form that are shipped in pressurized cylinders at ambient temperatures - Pressures in these cylinders may range from a few psi (kPa) to 15,000 psi (103 500 kPa) Liquefied gases are defined as gases kept liquefied under pressure. - Critical temperature and pressure of a gas refer to the temperature and pressure needed to liquefy the gas - Gas cannot be liquefied by pressure alone if above its critical temperature - CO~2~ has a critical temperature of 88°F (31°C) - Above this critical temperature, CO~2~ cannot be liquefied regardless of the amount of pressure applied to the product Cryogenic liquids are liquefied gases at very low temperatures. - U.S. DOT defines a cryogenic liquid as a refrigerated liquid having a boiling point lower than -130°F (-90°C) at 14.7 psi (103 kPa) - Distinction between cryogenic liquids and liquefied gases is that cryogens remain liquid at these low temperatures at atmospheric pressure - Cryogens also have high expansion ratios Cryogenic liquids, liquefied gases, and compressed gases have their own unique hazards. - Vaporizing liquid or the gas released from a pressurized cylinder may displace oxygen, causing asphyxiation - The extreme cold of cryogenic liquids and liquefied gases may cause severe frostbite and the destruction of exposed body tissue - Extreme cold of cryogenic liquids may cause metals to become brittle, leading to failure of the container, supporting structures, or other exposed metal parts - Rapid expansion of liquefied gases or cryogenic liquids can lead to the buildup of extremely high pressure and the violent failure of pressurized equipment, similar in effect to a BLEVE - Some pressurized gases may generate large static-electric charges when they are released, leading to the potential to ignite flammable atmospheres - Some cryogenic liquids and liquefied gases possess unique reactive hazards beyond the hazards associated with the same materials at ambient temperatures - Liquid oxygen can react with asphalt to form a powerful, sensitive contact explosive which can be detonated by the pressure of a single footstep - Liquid chlorine reacts violently with almost any organic material leading to extreme fire danger in the vicinity of a spill Materials can be characterized by their water content and reactions to water. - Anhydrous means "dry" or without water - Hydrophobic elements will repel water - Hydrophilic elements and materials absorb water Materials can also be characterized by their physical properties - Density - Specific gravity - Vapor density - Viscosity - Odor - Appearance Density is a measure of how heavy a unit volume of a substance is, or the mass of a known volume. - Density of a substance changes with temperature - Usually, as matter gets colder, it gets denser - As matter gets warmer, it gets less dense The comparison of densities tells you whether an item will sink or float in a type of liquid. - A wax candle will float in water, but sinks in rubbing alcohol because wax is less dense than water but more dense than the rubbing alcohol Density is useful to determine how heavy the material is. - When you look up density in a reference source, it is usually given in units of grams per milliliter (g/ml) - For hazardous materials response, a more useful measurement is pounds per grams (lb/g) - To convert g/ml to lb/gal, multiply g/ml by 8.34 NOTE - Grams per milliliter (g/ml) is the same measurement as grams per cubic centimeter (g/cc). Every solid and liquid in the environment occupies a specific volume of space. - Every solid and liquid has a certain weight at standard temperature and pressure - Water weighs 62.4 pounds per cubic foot (lb/ft^3^) or one gram per cubic centimeter (g/cm^3^) - Different materials will have different weights per volume Another way of expressing the weight of a solid or a liquid is specific gravity. - Specific gravity can be determined by dividing the density of a substance by the density of water Water has a specific gravity equal to 1. - If a material has a specific gravity less than 1, it is lighter than water and therefore would float on water - If a material has a specific gravity greater than 1, it will sink in water Reference manuals usually express specific gravity at a certain temperature. - Because specific gravity will vary depending on the temperature of the material - If the temperature of the material increases, the material will expand and the density will decrease - Therefore, the weight by volume will decrease Vapor density is the ratio of the density of pure gas or vapor to the density of air. - The density of air is equal to 1 - If a material has a vapor density less than 1, it is lighter than air and will rise - If a material has a vapor density greater than 1, then it is heavier than air and will sink The Compressed Gas Association (CGA) uses the specific gravity of the gas for vapor density. - While this may appear confusing, the numbers are the same - The NIOSH RgasD (relative gas density) measurement is identical to vapor density - NIOSH defines RgasD as the relative density of gases referenced (compared) to air, where air = 1 - Like vapor density, this value will indicate how many times a gas is heavier than air at the same temperature It is possible to estimate the vapor density of a material. - Divide the MW of the material by the average molecular weight of air (29) to obtain the estimated vapor density - Example - Chlorine has a MW of 71 - Dividing 71 by 29 yields an estimation of 2.45 - Reference materials list the vapor density at 2.49 - While not exact, this estimate is adequate for response - A product with a MW greater than 29 will sink; a MW less than 29 will rise NOTE - Hydrogen fluoride (HF) is the exception to this rule: HF vapor density is 3, but its molecular weight is 20. When discussing vapor density, the temperature of the vapor must also be considered. - Hot vapors will rise, but unless dispersed they will sink when cooled - Cold vapors are very dense and will tend to rise when they warm - Most materials are heavier than air Viscosity is the measure of the internal friction of a liquid at a given temperature. - Viscosity determines the ease with which a product will flow - Usually, the hotter a liquid, the thinner or more fluid it becomes - The cooler a liquid, the thicker or less fluid it becomes Odor is an expression of how people perceive chemical scents. - Some chemicals have little or no odor, while others have a strong characteristic odor - An unexpected odor may be a warning that a substance has escaped from its container - Callers/victims may provide odor characteristics when they alert authorities - Responders can use these reports for initial information, but must use detection and monitoring to evaluate an atmosphere WARNING - Inhalation of materials can cause injury or death. WARNING - Never attempt to use odors to define safe areas. Elements, compounds, and mixtures have a characteristic appearance consistent with their composition. - A description of the appearance of a material (physical state, color, etc.) will normally appear on a SDS - For example, a clear liquid may be described as "water white" - For many industrial products, the color listed on the SDS may represent an "average" - The product shipped may vary significantly in color and still be the same product - Significant difference in color may also show contamination or high levels of impurities that may have their own hazards Temperature is a variable that can affect the physical properties of a product. - Common temperature measurement scales are Celsius (°C) and Fahrenheit (°F) - Some measurements use other scientific scales such as Kelvin (K) or Rankine (°Ra) - Increasing heat in an object will increase the movement of molecules in the object Flammable liquids have flash points. - Flash point of a flammable liquid - The lowest temperature at which a liquid can form an ignitable mixture in air near the liquid's surface but will not support continuous burning Know the different definitions of flash point. - NFPA defines - Flammable liquids as products that have a flash point below 100°F (38°C) - Combustible liquids as products that have a flash point above 100°F (38°C) - U.S. DOT defines - Flammable liquid as having a flash point below 141°F (60°C) Flash point is expressed in terms of temperature of the liquid being tested. - The lower the flash point of a product, the higher the flammability of the product - Liquids do not burn - Vapors produced by the liquids actually burn Molecular weight is a factor that can affect the flash point of a product. - In general, the lower the molecular weight, the lower the flash point - If the product is liquid, the vapors are typically heavier than air - If a material has a high molecular weight, it will typically have a high flash point Viscosity is the measure of the internal friction of a liquid at a given temperature. - Viscosity determines the ease with which a product will flow - Usually, the hotter a liquid, the thinner or more fluid it becomes - The cooler a liquid, the thicker or less fluid it becomes Odor is an expression of how people perceive chemical scents. - Some chemicals have little or no odor, while others have a strong characteristic odor - An unexpected odor may be a warning that a substance has escaped from its container - Callers/victims may provide odor characteristics when they alert authorities - Responders can use these reports for initial information, but must use detection and monitoring to evaluate an atmosphere WARNING - Inhalation of materials can cause injury or death. WARNING - Never attempt to use odors to define safe areas. Elements, compounds, and mixtures\ have a characteristic appearance consistent with their composition. - A description of the appearance of a material (physical state, color, etc.) will normally appear on a SDS - For example, a clear liquid may be described as "water white" - For many industrial products, the color listed on the SDS may represent an "average" - The product shipped may vary significantly in color and still be the same product - Significant difference in color may also show contamination or high levels of impurities that may have their own hazards Temperature is a variable that can affect the physical properties of a product. - Common temperature measurement scales are Celsius (°C) and Fahrenheit (°F) - Some measurements use other scientific scales such as Kelvin (K) or Rankine (°Ra) - Increasing heat in an object will increase the movement of molecules in the object Flammable liquids have flash points. - Flash point of a flammable liquid - The lowest temperature at which a liquid can form an ignitable mixture in air near the liquid's surface but will not support continuous burning Know the different definitions of flash point. - NFPA defines - Flammable liquids as products that have a flash point below 100°F (38°C) - Combustible liquids as products that have a flash point above 100°F (38°C) - U.S. DOT defines - Flammable liquid as having a flash point below 141°F (60°C) Flash point is expressed in terms of temperature of the liquid being tested. - The lower the flash point of a product, the higher the flammability of the product - Liquids do not burn - Vapors produced by the liquids actually burn Molecular weight is a factor that can affect the flash point of a product. - In general, the lower the molecular weight, the lower the flash point - If the product is liquid, the vapors are typically heavier than air - If a material has a high molecular weight, it will typically have a high flash point Other variables that can affect the state of a product include molecular weight and polarity. - Polarity - Molecules and atoms have a decreased distance between each other because of the intermolecular attraction caused by their polarity Given the right conditions, matter can change its state from a solid to a liquid, from a liquid to a gas, and back again. - Chemical composition is unchanged - When a substance changes from one state of matter to another, we say that it has undergone a "change of state" or a "change of phase" - These changes of phase always occur with a change of heat - Heat, which is energy, either comes into the material during a change of phase or heat goes out of the material during this change A material's temperature will influence both the range of hazards and potential countermeasures. - As a normal rule, materials contract when they get cold and expand when they get hot - Significant exceptions apply - For example, water expands when it freezes, and has sufficient pressure to rupture containers The temperature at which a solid turns into a liquid is called its melting point. - The melting point is a critical property to analyze for emergency response - Solid material may change to a liquid if heated sufficiently - It is typically easier to control a solid than a liquid The freezing point is the temperature at which a liquid will solidify or crystallize. - The freezing point is typically the same as or similar to the temperature of the melting point - There are some exceptions - Some materials are known to "supercool" - They do not crystallize or freeze at the same temperature they melted - The liquid may need to be 5 or 10 degrees cooler before it starts to crystallize or solidify The boiling point is the temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure. - Boiling is a process in which molecules anywhere in the liquid escape, resulting in the formation of vapor bubbles within the liquid - The standard boiling point is defined as the temperature at which boiling occurs under a pressure of 1 bar (1 atmosphere) Water boils at different temperatures depending on the altitude and additives. Liquids may change to vapor at temperatures below their boiling points through the process of evaporation. - Evaporation is a surface phenomenon in which molecules located near the liquid's edge escape into the atmosphere as vapor - Evaporation rate is the speed at which some material changes from a liquid to a vapor - Temperatures will affect evaporation rates - The hotter the temperature, the faster the evaporation rate - The colder the temperature, the slower the evaporation rate Some materials change to a vapor more easily than others. - Volatility - Materials that change readily to gases are termed volatile - Usually reported as a comparative value versus another compound Condensation is the conversion of a vapor into a liquid as it is cooled down to, or below, the liquid's boiling point. - Once the temperature of a liquid drops below its boiling point - Vapors that are produced will start to cool and form condensation - Vapors will start to condense back to a liquid **Sublimation is the transformation of a material from a solid into a vapor\ without passing through a liquid state.** - **Example** - **Dry ice is a solid form of carbon dioxide that is used as a cooling agent in many commercial applications** - **When vaporization occurs** - **The material goes from a solid to a gas without becoming a liquid** - **Iodine** - **Will easily sublimate** - **May encounter in areas where illicit methamphetamine is produced** - **Has the ability to travel until it finds a cool spot where it can condense, causing movement of this hazardous chemical to other locations within a production area** **Critical points are behaviors that can harm people.** - **When a material reaches any critical point, the chemical reaction initiated by that threshold cannot be stopped until the reaction is completed** **There are several critical points with regards to the temperature and pressure of hazardous materials.** - **Critical temperature** - **The minimum temperature above which a gas cannot be liquefied no matter how much pressure is applied** - **Critical pressure** - **The pressure necessary to liquefy a gas at its critical temperature** - **Autoignition temperature** - **The lowest temperature at which a substance will ignite in air when there is no ignition source** **There are several critical points with regards to the temperature and pressure of hazardous materials.** - **Self-accelerating decomposition temperature (SADT)** - **The temperature above which the decomposition of an unstable substance continues unimpeded, regardless of the ambient or external temperature** - **Maximum safe storage temperature (MSST)** - **The maximum safe temperature at which a product can be stored** - **This temperature is well below the SADT** - **Polymerization** - **A special chemical reaction in which small-molecule compounds called monomers react with themselves to form larger molecules called polymers** **Understand the relationship between temperature and pressure.** - **As temperature increases and decreases, pressure does the same** - **As the temperature of matter increases, so does the speed of its molecules** - **Pressure in turn rises due to the molecules' force on the container** **Temperature and pressure are directly proportional to one another.** **Understanding physical properties can help hazmat technicians understand the product involved in an incident.** - **If a material has a low boiling point** - **Can presume flash point will also be low** - **Product with low boiling point and flash point will produce a large quantity of vapor --- thus the product will have a high vapor pressure and vapor content** - **If a material has a high boiling point and flash point** - **Can presume vapor pressure and vapor content will also be low** **Vapor pressure and vapor content are related.**