Chemistry
Physical Properties
Physical properties refer to the characteristics of a substance that can be observed or measured without changing the substance's chemical composition. These properties include attributes such as color, density, melting point, boiling point, and conductivity. They are used to identify and classify substances and are important in understanding how materials behave under different conditions.
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12 Key excerpts on "Physical Properties"
eBook - PDF- John Kenkel(Author)
- 2010(Publication Date)
- CRC Press(Publisher)
There are two kinds of properties: Physical Properties and chemical properties . Physical Properties are physical characteristics that might be determined by simple observation or measurement and involve no chemical change . Most of the examples just listed—namely color, odor, taste, physical appearance, physical state (solid, liquid, or gas), and solubility—are Physical Properties . All of these may be determined by simple observation with one of the five senses, such as sight (e .g ., color, sheen, physical state,) or smell (e .g ., odor) . Other Physical Properties require measurement, and some of these require calculations . Examples are melting point, boiling point, and density . Melting point, the temperature at which a solid substance is converted to a liquid (such as 32°F [0°C] for ice to water), and boiling point, the temperature at which a liquid substance boils (such as 212°F [100°C] for water) require the measure-ment of temperature . Because of this, these Physical Properties have numbers associated with them . They are Physical Properties because they are charac-teristics by which water may be described or identified through simple obser-vation or measurement . Density is a physical property that indicates how heavy a substance is compared with how much space it occupies (its volume) . Considering two metal blocks of equal size—one made of aluminum and one made of lead—it is easy to understand the concept . The lead block is much heavier than the aluminum block in spite of the fact that the blocks have the same volume . Lead has a greater density, or greater mass or weight, per given volume . Density is something that is measured and requires a calculation to know what it is . In a chemistry laboratory, it is easy to measure the weight of a quantity of matter, and it can also be easy to measure volume . Density is calculated by dividing the measured weight by the measured volume .
eBook - PDF- Morris Hein, Susan Arena, Cary Willard(Authors)
- 2021(Publication Date)
- Wiley(Publisher)
Common Physical Properties include color, taste, odor, state of matter (solid, liquid, or gas), density, melting point, and boiling point (Fig- ure 4.1). Chemical properties describe the ability of a substance to form new substances, either by reaction with other substances or by decomposition. 4.1 Properties of Substances 71 Table 4.1 Physical Properties of Selected Substances Substance Color Odor Physical state Melting point (°C) Boiling point (°C) Chlorine Greenish yellow Sharp, suffocating Gas (20°C) −101.6 −34.6 Water Colorless Odorless Liquid 0.0 100.0 Sugar White Odorless Solid — Decomposes 170–186 Acetic acid Colorless Like vinegar Liquid 16.7 118.0 Nitrogen dioxide Reddish brown Sharp, suffocating Gas −11.2 21.2 Oxygen Colorless Odorless Gas −218.4 −183 Substances, then, are recognized and differentiated by their properties. Table 4.1 lists six substances and several of their common Physical Properties. Information about Physical Properties, such as that given in Table 4.1, is available in handbooks of chemistry and phys- ics. Scientists don’t pretend to know all the answers or to remember voluminous amounts of data, but it is important for them to know where to look for data in the literature and on the Internet. Many chemists have reference books such as the Handbook of Chemistry and Physics or use the internet as a resource. No two substances have identical physical and chemical properties. Chemistry in Action Making Money Chemists are heavily involved in the manufacture of our cur- rency. In fact, in a very real way, the money industry depends on chemistry and finding substances with the correct properties. The most common paper currency in the United States is the dollar bill. Chemistry is used to form the ink and paper and in processes used to defeat counterfeiters. The ink used on currency has to do a variety of things. It must be just the right consistency to fill the fine lines of the printing plate and release onto the paper without smearing.
eBook - PDF- Morris Hein, Susan Arena, Cary Willard(Authors)
- 2016(Publication Date)
- Wiley(Publisher)
Physical Properties are the inherent characteristics of a substance that can be determined without altering its composition; they are associated with its physical existence. Common Physical Properties include color, taste, odor, state of matter (solid, liquid, or gas), density, melting point, and boiling point (FIGURE 4.1). Chemical properties describe the ability of a substance to form new substances, either by reaction with other substances or by decomposition. Martin Dohrn/Science Source Images FIGURE 4.2 Chemical property: When sodium metal reacts with chlorine gas, a new substance called sodium chloride forms. Na + Cl – Na + Cl – Chlorine gas Sodium chloride Sodium metal + + Na atom Cl 2 molecules Andrew Lambert Photography/ Science Source Images Charles D. Winters/Science Source Images Christoph Ermel/iStockphoto FIGURE 4.1 Physical property: The boiling point of water is a physical property. At its boiling point water changes from a liquid to a gas, but the molecules remain water molecules. Although the molecules are farther apart, they are still water. LEARNING OBJECTIVE KEY TERMS properties Physical Properties chemical properties Let’s consider a few of the physical and chemical properties of chlorine. Physically, chlo- rine is a gas at room temperature about 2.4 times heavier than air. It is greenish yellow in color and has a disagreeable odor. Chemically, chlorine will not burn but will support the combustion of certain other substances. It can be used as a bleaching agent, as a disinfectant for water, and in many chlorinated substances such as refrigerants and insecticides. When chlorine combines with the metal sodium, it forms a salt called sodium chloride ( FIGURE 4.2). These properties, among many others, help us characterize and identify chlorine. CHECK YOUR UNDERSTANDING 4.1 Physical Properties 4.2 Chemical Properties ➥
- Morris Hein, Scott Pattison, Susan Arena, Leo R. Best(Authors)
- 2014(Publication Date)
- Wiley(Publisher)
Properties—the “personality traits” of substances—are classified as either physical or chemical. Physical Properties are the inher- ent characteristics of a substance that can be determined without altering its composition; they are associated with its physical existence. Common Physical Properties include color, taste, odor, state of matter (solid, liquid, or gas), density, melting point, and boiling point (see Figure 4.1). Chemical properties describe the ability of a substance to form new substances, either by reaction with other substances or by decomposition. Let’s consider a few of the physical and chemical properties of chlorine. Physically, chlorine is a gas at room temperature about 2.4 times heavier than air. It is greenish yellow in color and has a disagreeable odor. Chemically, chlorine will not burn but will support the combustion of certain other substances. It can be used as a bleaching agent, as a disinfectant for water, and in many chlorinated substances such as refriger- ants and insecticides. When chlorine combines with the metal sodium, it forms a salt called sodium chloride (see Figure 4.2). These properties, among many others, help us characterize and identify chlorine. KEY TERMS properties Physical Properties chemical properties Figure 4.2 Chemical property. When sodium metal reacts with chlorine gas, a new substance called sodium chloride forms. Martin Dohrn/Photo Researchers, Inc. + ¡ + ¡ Chlorine gas Sodium chloride Na atom Sodium metal Na + Cl – Na + Cl – 2 molecules Cl Andrew Lambert Photography/ Photo Researchers, Inc. Charles D. Winters/Photo Researchers, Inc. Christoph Ermel/iStockphoto Figure 4.1 Physical property. The boiling point of water is a physical property. At its boiling point water changes from a liquid to a gas, but the molecules remain water molecules. They are still water but are farther apart. LEARNING OBJECTIVE
eBook - PDF- Satinder Ahuja, Neil Jespersen(Authors)
- 2006(Publication Date)
- Elsevier Science(Publisher)
Chapter 3 Evaluation of basic Physical Properties Neil Jespersen 3.1 INTRODUCTION Some of the simplest techniques and instruments are valuable tools for chemical analysis. This chapter is designed to remind students that simple, rapid methods are advantageous in many situations. These methods are often used for quality control purposes. The methods dis-cussed here are melting and boiling points, viscosity, density or specific gravity and refractive index. Time is often an important consideration in practical chemical ana-lysis. Raw materials awaiting delivery in tanker trucks or tractor-trailers often must be approved before they are offloaded. Batches of product prepared by compounders on the factory floor must be analyzed and approved before the packaging process can begin. Analysis is often per-formed again on packaged products before they are sent to the ware-house. To maintain a smoothly running manufacturing system, the analytical chemist must have rapid, informative methods to assay a wide variety of samples. Also important in quality control is the establishment of standards that are agreed upon by all involved in the manufacturing process. Lax enforcement of standards brings into question the utility of the analysis and threatens product quality. Observation and measurement of Physical Properties are the oldest known means of assessing chemical purity and establishing identity. Their utility comes from the fact that the vast majority of chemical compounds have unique values for their melting points, boiling points, density and refractive index. In addition, viscosity and conductance are rapid methods for overall properties of substances. The Handbook of Chemistry and Physics has approximately 100 tables listing the refrac-tive index, density, specific gravity, viscosity and conductivity of aque-ous solutions of common inorganic and organic solutes at varying concentrations.
eBook - ePubHazardous Substances
Risks and Regulations
- Thomas Schupp(Author)
- 2020(Publication Date)
- De Gruyter(Publisher)
2 Physical and chemical properties of substancesUnderstanding physical and chemical properties of substances is a prerequisite for proper understanding of not only physical–chemical hazards, but also for the understanding of substance behavior in the environment and in organisms.Environmental behavior covers the emission, distribution and fate of a substance in the environment, and this perspective shows similarities to the adsorption, distribution, metabolism and excretion (ADME) of a substance in an organism as discussed in Chapter 3, if an ecosystem (or nature) is regarded as an organism.Physical–chemical properties of substances are part of their identification, and in the field of hazardous substances and risk assessment, proper identification and characterization is crucial for the success of toxicological and environmental investigations. This chapter starts with the identification of substances.2.1 Identification of substances
Identification of a substance starts with simple Physical Properties that can be checked quickly and without sophisticated equipment. For solids, it is the melting point and visual appearance; for liquids, it is the refraction index, perhaps extended to boiling point, viscosity and density. These methods may provide a hint on purity, already, and it may occur that some limited data on identification are sufficient to check the specification of a product agreed upon between supplier and customer. Nevertheless, a more in-depth check on purity or identification of impurities can be very important. Just as one example: the substance aniline was the parent for the name “aniline-cancer,” describing bladder cancer that was comparatively frequently detectable in workforces in aniline production plants. Later, it turned out that impurities in the technical aniline – namely benzidine and 2-naphthylamine – were the causative agents. To detect and quantify such by-products and impurities, spectrometric and chromatographic methods are required. The European chemicals regulation actually requires the full characterization of a “mono-constituent” substance (see Chapter 8) submitted for registration by UV, IR, NMR and MS spectra, as far as appropriate, and to make use of chromatographic methods [gas chromatography (GC), high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC)] to identify every component that contributes to at least 0.1% to the technical substance. Lower detection limits may be required if the presence of specific critical impurities cannot be excluded.
- Kevin Dahm, Donald Visco(Authors)
- 2014(Publication Date)
- Cengage Learning EMEA(Publisher)
Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 59 C H A P T E R 2 The Physical Properties of Pure Compounds Example 2-1 introduced the quality ( q ) of a system in vapor–liquid equilibrium , which is the fraction of mass that is in the vapor phase . It also illustrated how intensive properties representing a multiphase equilibrium system can be computed using a weighted aver-age of the intensive properties of the individual phases. If a system consists of liquid and vapor in equilibrium, an intensive property of the overall system can be computed as M 5 s 1 2 q d M L 1 qM V (2.11) where M can represent any intensive property (e.g., specific enthalpy or molar entropy) and q represents the quality. 2.3 Thermodynamic Models of Physical Properties Pressure, volume, and temperature are easily measured properties of materials that have great practical significance in both engineering and thermodynamics. Section 1.4.6 described internal energy, which cannot be measured directly but is a fundamental quantity in chemical engineering thermodynamics. Sections 2.2.1 and 2.2.2 outlined the importance of quantifying the interrelationships between various physical prop-erties of compounds, but they also noted that the relevant data is not always available. This section begins the process of developing mathematical models that quantify the interrelationships among the key thermodynamic properties of materials. 2.3.1 Enthalpy Enthalpy is another state property that quantifies energy. Like internal energy, it cannot be measured directly and cannot be known in an absolute sense, but it is quantified relative to a reference state. This section introduces and explores how enthalpy is useful in solving problems. Recall that the rate of flow work is equal to W · 5 PV · 5 m · PV ˆ (2.12) A chemical plant is shown in Figure 2-7.
eBook - PDF- R. E. Smallman, A.H.W. Ngan(Authors)
- 2011(Publication Date)
- Butterworth-Heinemann(Publisher)
Chapter 5 Physical Properties 5.1 Introduction The ways in which any material interacts and responds to various forms of energy are of prime interest to scientists and, in the context of engineering, provide the essential base for design and innovation. The energy acting on a material may derive from force fields (gravitational, electric, magnetic), electromagnetic radiation (heat, light, X-rays), high-energy particles, etc. The responses of a material, generally referred to as its Physical Properties, are governed by the structural arrangement of atoms/ions/molecules in the material. The theme of the structure–property relation which has run through previous chapters is developed further. Special attention will be given to the diffusion of atoms/ions within materials because of the importance of thermal behavior during manufacture and service. In this brief examination, which will range from density to superconductivity, the most important Physical Properties of materials are considered. 5.2 Density This property, defined as the mass per unit volume of a material, increases regularly with increasing atomic numbers in each subgroup. The reciprocal of the density is the specific volume v , while the product of v and the relative atomic mass W is known as the atomic volume . The density may be determined by the usual ‘immersion’ method, but it is instructive to show how X-rays can be used. For example, a powder photograph may give the lattice parameter of an fcc metal, say copper, as 0.36 nm. Then 1 / (3 . 6 × 10 − 10 ) 3 or 2.14 × 10 28 cells of this size (0.36 nm) are found in a cube of 1 m edge length. The total number of atoms in 1 m 3 is then 4 × 2.14 × 10 28 = 8.56 × 10 28 since an fcc cell contains four atoms. Furthermore, the mass of a copper atom is 63.57 times the mass of a hydrogen atom (which is 1.63 × 10 − 24 g) so that the mass of 1 m 3 of copper, i.e. the density, is 8.56 × 10 28 × 63.57 × 1.63 × 10 − 24 = 8900 kg m − 3 .
eBook - PDF- Leo J. Malone, Theodore O. Dolter(Authors)
- 2012(Publication Date)
- Wiley(Publisher)
p. 102 3-4.3 Energy may be either used as kinetic energy or stored as potential energy. p. 102 3-5 Specific heat is a physical property that interrelates heat, mass, and temperature change. p. 102 3-5.1 Heat is measured in joules or calories. p. 103 110 CHAPTER 3 The Properties of Matter and Energy YOUR TURN Windshield-washing solvent is a solution of methanol and water (and a small amount of detergent which we will neglect in this problem). a. Determine the volume of water (density = 0.9971 g/mL) that must be combined with 375 mL of methanol (density = 0.7914 g/mL) to make a 45.0% by mass methanol solution. b. Determine the total mass of the solution. c. Determine the amount of heat (in kJ) that is required to warm the solution from 25.0C to 55.0C. The specific heat of the solution is 3.52 J/g # C Answers are on p. 111. Elements and compounds are distinguished by their prop- erties. They display Physical Properties and undergo physi- cal changes. An important physical property of a substance is its physical state: solid, liquid, or gas. A physical change takes place when the substance changes to a different physical state. The temperatures at which an element or compound changes to a different phase are known as the melting point of a solid (or freezing point of a liquid) and boiling point of a liquid (or condensation point of a gas). A pure substance also has chemical properties that relate to the chemical changes it undergoes. In chemical changes the law of conservation of mass is observed. An important physical property of a substance is its den- sity. Density relates the mass of a substance to its volume; thus, it is independent of the size of the sample. Mass and volume are extensive properties, which may vary. Density is independent of the amount present, so it is an intensive property. Density can be used as an identifying property as well as a conversion factor between the mass and volume of a sample.
eBook - ePubActive Pharmaceutical Ingredient Manufacturing
Nondestructive Creation
- Girish K. Malhotra(Author)
- 2022(Publication Date)
- De Gruyter(Publisher)
Tab. 3.1 are of high value, and when used result in process design that will produce quality products. It is not necessary that each of the property mentioned may be needed or used in the design. Properties of raw materials used in production of active pharmaceutical ingredients (APIs), produced intermediates and formulations that may not be commonly available. Their physical property data might have to be generated theoretically and checked experimentally.Tab. 3.1: Chemical and Physical Properties of chemicals [2 ].Physical Properties Chemical properties - Mass
- Density
- Melting/freezing point
- Boiling point
- Viscosity
- Solubility
- Azeotrope
- Heat of formation
- Heat of reaction
- pH
- Surface tension
- Flammability
- Toxicity
- Hygroscopic
Before internet, many trade publications and companies published physical and chemical property data. In 1960s and 1970s, chemical engineering [3 ] and hydrocarbon processing [4 ] magazines published 24 and 44 articles, respectively, about physical and thermodynamic properties of hydrocarbons. Other publications [5 ] detailing Physical Properties are also available. Companies do provide Physical Properties and safe handling procedures [6 ]. Most of this information is available to potential customers only.With the advent of internet, physical and chemical property data can be accessed from these sources [7 , 8 , 9 , 10 ]. Sometimes data needed for specific needs has to be generated by the user in the laboratory.Most companies provide material safety data sheets (MSDS) that meet the regulatory requirements but do not have detailed properties which are needed and used for meaningful and safe process design. If additional information is needed, it might be available if one is a customer. Figure 3.1 shows parts of a typical safety data sheet (SDS) [11 ]. Each supplier has to provide SDS.Fig. 3.1:
eBook - PDF- William F. Gale, Terry C. Totemeier(Authors)
- 2003(Publication Date)
- Butterworth-Heinemann(Publisher)
14 General Physical Properties 14.1 The Physical Properties of pure metals Many Physical Properties depend on the purity and physical state (annealed, hard drawn, cast, etc.) of the metal. The data in Tables 14.1 and 14.2 refer to metals in the highest state of purity available, and are sufficiently accurate for most purposes. The reader should, however, consult the references before accepting the values quoted as applying to a particular sample. Table 14.1 THE Physical Properties OF PURE METALS AT NORMAL TEMPERATURES Mean Thermal specific Resistivity (10 − 8 m) Temp. coeff. Melting Boiling Density conductivity heat at T ( ◦ C) [iv] of resistivity Coeff.
- Carl L. Yaws(Author)
- 1997(Publication Date)
- Gulf Professional Publishing(Publisher)
Chapter 1 Physical Properties Carl L. Yaws Lamar University, Beaumont, Texas ABSTRACT Results for physical property data are presented for major hydrocarbons and organic chemicals. The Physical Properties include molecular weight, freezing point, boiling point, critical constants (temperature, pressure and volume), acentric factor and density. A wide range of compounds are covered including oxygen, nitrogen, chlorine, fluorine, bromine, sulfur, silicon and other chemical types. Physical Properties The results for Physical Properties are shown in Table 1-1. The results are presented in an easy-to-use tabular format which is especially applicable for rapid engineering usage with the personal computer or hand calculator. The tabulation is based on both experimental data and estimated values. A comparison of estimates and data is shown in Figure 1-1 for critical temperature of normal alkanes. The graph discloses favorable agreement of estimates and data. In the data collection, a literature search was conducted to identify data source publications (1-40). The publications were screened and copies of appropriate data were made. These data were then keyed into the computer to provide a data base of critical properties for compounds for which experimental data are available. The data base also served as a basis to check the accuracy of the estimation methods. Upon completion of data collection, estimation of the critical properties for the remaining compounds was performed using the group contribution method of Joback as given by Reid, Prausnitz and Poling (24). A comparison of the estimates with experimental data was favorable with average absolute errors of only 0.9 %, 6.3 %, and 4.4 % for critical temperature (465 compounds), pressure (453 compounds) and volume (345 compounds). The normal boiling and freezing point temperatures in the table are based on experimental data for most of the compounds.
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