Mar 20, · A crystalline solid can be represented by its unit cell, which is the smallest identical unit that when stacked together produces the characteristic three-dimensional structure. Solids are characterized by an extended three-dimensional arrangement of atoms, ions, or molecules in which the components are generally locked into their positions. A solid with a definite chemical makeup and structure is a pure substance that can be either an element or a compound. What is a natural nonliving solid with a definite chemical structure?
What is this information? Department of Transportation hazard labels, and a general description of the chemical. Diamond Hazard Value Description 1 2 0 Health 2 Can cause temporary incapacitation or residual injury. Flammability 1 Must be preheated before ignition can occur. Instability 0 Normally stable, even under fire structuree. A pale yellow crystalline solid with a faint solir of rotten eggs. Insoluble in water. Transported as cyemical yellow to red liquid.
Hot enough that plastic or rubber may melt or lose strength. Causes thermal burns to skin on contact. Cools rapidly and solidifies if released. Equipment designed to protect against ordinary chemical exposure is ineffective against the thermal hazard.
Exercise caution walking on the surface of a spill to avoid breakthrough into pockets of molten sulfur below the crust. Do not attempt to remove sulfur impregnated clothing because of the danger of tearing flesh if a burn has resulted.
May be irritatin to skin, eyes and mucous membranes. Used in sulfuric acid production, petroleum refining, and pulp and paper manufacturing. The Tbe fields include special hazard alerts air what is a conforming mortgage loan water reactions, fire hazards, health hazards, a reactivity profile, and details about reactive groups assignments and potentially incompatible absorbents. Highly Flammable Strong Reducing Agent.
Sloid Hazards of Combustion Products: Produces toxic sulfur dioxide gas. Behavior in Fire: Burns with a pale blue flame that may be difficult solld see in daylight. USCG, Can cause eye irritation; may rarely irritate skin. If recovered sulfur, refer to hydrogen sulfide. Reacts with iron to give pyrophoric compounds. Attacks copper, silver and mercury. Ignites in fluorine gas at ordinary temperatures [Mellor ].
Reacts to incandescence with heated with thorium [Mellor ]. Can react with ammonia to form explosive sulfur nitride. Reacts violently with phosphorus trioxide [Chem. News ]. Mixtures with ammonium nitrate or with metal powders can be exploded by whwt [Kirk and Othmer ].
Combinations of finely divided sulfur with finely divided bromates, chlorates, or iodates of barium, calcium, magnesium, potassium, sodium, or zinc can explode with heat, friction, percussion, and sometimes light [Mellor 2 Supp.
Attacks heated lithium, or heated selenium carbide with incandescence [Mellor ]. Reacts explosively if warmed with powdered zinc [Mellor Reacts vigorously with tin [Mellor A mixture with potassium nitrate and arsenic trisulfide is a known pyrotechnic formulation [Ellern p.
Mixtures with any perchlorate can explode on impact [ACS ]. A mixture of damp sulfur and calcium hypochlorite produces a brilliant crimson flash with scatter of molten sulfur [Chem. News strkcture 28 :9 ]. Takes fire spontaneously in chlorine dioxide and may produce an explosion [Mellor ]. Ignites if heated with chromic anhydride ignite and can explode, [Mellor ]. Even small percentages of hydrocarbons in contact with structjre sulfur generate hydrogen sulfide and carbon disulfide, which may accumulate in explosive concentrations.
Sulfur reacts with Group I metal nitrides to chemicsl flammable mixtures, evolving flammable and toxic NH3 and H2S gases if water is present Mellor,Vol. Reducing Agents, Strong. The Response Recommendation fields include isolation and evacuation distances, as well as recommendations for firefighting, non-fire response, protective clothing, and first aid.
Excerpt from ERG Guide [Flammable Solids]: As an immediate cute is what we aim for vinyl measure, isolate spill or leak area for at least 25 meters 75 feet in all directions. ERG, Move containers from fire area if you can do it without risk. Fire Involving Metal Pigments or Pastes e. Also, see ERG Guide For massive fire, structurd unmanned hose holders or monitor nozzles; if this is impossible, withdraw from area and let fire burn.
Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. Do not touch or walk through spilled material. Prevent entry into waterways, sewers, basements or confined areas. Safety goggles with side shields; approved respirator; heat-resistant sttructure leather heat-resistant clothing. EYES: wash eyes carefully for at least 15 min. SKIN: Treat molten sulfur burns with petroleum jelly or mineral oil. If recovered sulfur, treat as for hydrogen sulfide.
The Physical Property fields include properties such as vapor pressure and boiling o, as well as explosive limits and toxic exposure thresholds The information in CAMEO Chemicals comes from a variety of data sources. Vapor Density Relative to Air : data unavailable. Specific Gravity: 1. Boiling Point: Molecular Weight: The Regulatory Information fields include tsructure from the U.
This section provides a listing of alternate names for iz chemical, including trade names and synonyms. Flammable Solid international Class 9 domestic.
Feb 01, · A solid is a state of matter characterized by particles arranged such that their shape and volume are relatively stable. The constituents of a solid tend to be packed together much closer than the particles in a gas or liquid. The reason a solid has a rigid shape is that the atoms or molecules are tightly connected via chemical bonds. 1. Introduction Classifications for solids (examples) Degree of order • Long range order: crystals (3D periodicity) • Long range order with extended defects (dislocations) • Crystals with disorder of a partial structure (ionic conductors) • Amorphous solids, glasses (short range order) Chemical bonding – typical properties • Covalent solids (e.g. diamond, boron nitride): extreme. Chemical bonding - Chemical bonding - Molecular solids: The structures of molecular solids, which are solids composed of individual molecules, have also been touched on in the section on intermolecular forces. These molecules are held to one another by hydrogen bonds (if they can form them), dispersion forces, and other dipolar forces—in that order of decreasing importance—and the.
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur.
The substance or substances initially involved in a chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change , and they yield one or more products , which usually have properties different from the reactants. Reactions often consist of a sequence of individual sub-steps, the so-called elementary reactions , and the information on the precise course of action is part of the reaction mechanism. Chemical reactions are described with chemical equations , which symbolically present the starting materials, end products, and sometimes intermediate products and reaction conditions.
Chemical reactions happen at a characteristic reaction rate at a given temperature and chemical concentration. Typically, reaction rates increase with increasing temperature because there is more thermal energy available to reach the activation energy necessary for breaking bonds between atoms.
Reactions may proceed in the forward or reverse direction until they go to completion or reach equilibrium. Reactions that proceed in the forward direction to approach equilibrium are often described as spontaneous , requiring no input of free energy to go forward.
Non-spontaneous reactions require input of free energy to go forward examples include charging a battery by applying an external electrical power source, or photosynthesis driven by absorption of electromagnetic radiation in the form of sunlight.
A reaction may be classified as redox in which oxidation and reduction occur or nonredox in which there is no oxidation and reduction occurring. Most simple redox reactions may be classified as combination, decomposition, or single displacement reactions.
Different chemical reactions are used during chemical synthesis in order to obtain a desired product. In biochemistry , a consecutive series of chemical reactions where the product of one reaction is the reactant of the next reaction form metabolic pathways. These reactions are often catalyzed by protein enzymes. Enzymes increase the rates of biochemical reactions, so that metabolic syntheses and decompositions impossible under ordinary conditions can occur at the temperatures and concentrations present within a cell.
The general concept of a chemical reaction has been extended to reactions between entities smaller than atoms, including nuclear reactions , radioactive decays , and reactions between elementary particles , as described by quantum field theory. Chemical reactions such as combustion in fire, fermentation and the reduction of ores to metals were known since antiquity. Initial theories of transformation of materials were developed by Greek philosophers, such as the Four-Element Theory of Empedocles stating that any substance is composed of the four basic elements — fire, water, air and earth.
In the Middle Ages , chemical transformations were studied by alchemists. They attempted, in particular, to convert lead into gold , for which purpose they used reactions of lead and lead-copper alloys with sulfur.
The artificial production of chemical substances already was a central goal for medieval alchemists. In the 17th century, Johann Rudolph Glauber produced hydrochloric acid and sodium sulfate by reacting sulfuric acid and sodium chloride. With the development of the lead chamber process in and the Leblanc process , allowing large-scale production of sulfuric acid and sodium carbonate , respectively, chemical reactions became implemented into the industry. Further optimization of sulfuric acid technology resulted in the contact process in the s,  and the Haber process was developed in — for ammonia synthesis.
From the 16th century, researchers including Jan Baptist van Helmont , Robert Boyle , and Isaac Newton tried to establish theories of the experimentally observed chemical transformations. The phlogiston theory was proposed in by Johann Joachim Becher.
It postulated the existence of a fire-like element called "phlogiston", which was contained within combustible bodies and released during combustion. This proved to be false in by Antoine Lavoisier who found the correct explanation of the combustion as reaction with oxygen from the air. Joseph Louis Gay-Lussac recognized in that gases always react in a certain relationship with each other. Based on this idea and the atomic theory of John Dalton , Joseph Proust had developed the law of definite proportions , which later resulted in the concepts of stoichiometry and chemical equations.
Regarding the organic chemistry , it was long believed that compounds obtained from living organisms were too complex to be obtained synthetically. According to the concept of vitalism , organic matter was endowed with a "vital force" and distinguished from inorganic materials. Other chemists who brought major contributions to organic chemistry include Alexander William Williamson with his synthesis of ethers and Christopher Kelk Ingold , who, among many discoveries, established the mechanisms of substitution reactions.
Chemical equations are used to graphically illustrate chemical reactions. They consist of chemical or structural formulas of the reactants on the left and those of the products on the right. Equations should be balanced according to the stoichiometry , the number of atoms of each species should be the same on both sides of the equation. More elaborate reactions are represented by reaction schemes, which in addition to starting materials and products show important intermediates or transition states.
Also, some relatively minor additions to the reaction can be indicated above the reaction arrow; examples of such additions are water, heat, illumination, a catalyst , etc.
Similarly, some minor products can be placed below the arrow, often with a minus sign. Retrosynthetic analysis can be applied to design a complex synthesis reaction. Here the analysis starts from the products, for example by splitting selected chemical bonds, to arrive at plausible initial reagents.
The elementary reaction is the smallest division into which a chemical reaction can be decomposed, it has no intermediate products. The actual sequence of the individual elementary reactions is known as reaction mechanism. An elementary reaction involves a few molecules, usually one or two, because of the low probability for several molecules to meet at a certain time. The most important elementary reactions are unimolecular and bimolecular reactions.
Only one molecule is involved in a unimolecular reaction; it is transformed by an isomerization or a dissociation into one or more other molecules. Such reactions require the addition of energy in the form of heat or light. A typical example of a unimolecular reaction is the cis—trans isomerization , in which the cis-form of a compound converts to the trans-form or vice versa. In a typical dissociation reaction, a bond in a molecule splits ruptures resulting in two molecular fragments.
The splitting can be homolytic or heterolytic. In the first case, the bond is divided so that each product retains an electron and becomes a neutral radical. In the second case, both electrons of the chemical bond remain with one of the products, resulting in charged ions. Dissociation plays an important role in triggering chain reactions , such as hydrogen—oxygen or polymerization reactions. For bimolecular reactions, two molecules collide and react with each other.
Their merger is called chemical synthesis or an addition reaction. Another possibility is that only a portion of one molecule is transferred to the other molecule.
This type of reaction occurs, for example, in redox and acid—base reactions. In redox reactions, the transferred particle is an electron, whereas in acid—base reactions it is a proton.
This type of reaction is also called metathesis. Most chemical reactions are reversible; that is, they can and do run in both directions. The forward and reverse reactions are competing with each other and differ in reaction rates. These rates depend on the concentration and therefore change with time of the reaction: the reverse rate gradually increases and becomes equal to the rate of the forward reaction, establishing the so-called chemical equilibrium.
The time to reach equilibrium depends on parameters such as temperature, pressure, and the materials involved, and is determined by the minimum free energy. In equilibrium, the Gibbs free energy must be zero. The pressure dependence can be explained with the Le Chatelier's principle.
For example, an increase in pressure due to decreasing volume causes the reaction to shift to the side with the fewer moles of gas. The reaction yield stabilizes at equilibrium, but can be increased by removing the product from the reaction mixture or changed by increasing the temperature or pressure.
A change in the concentrations of the reactants does not affect the equilibrium constant, but does affect the equilibrium position. Chemical reactions are determined by the laws of thermodynamics. Reactions can proceed by themselves if they are exergonic , that is if they release energy.
The associated free energy of the reaction is composed of two different thermodynamic quantities, enthalpy and entropy : . Typical examples of exothermic reactions are precipitation and crystallization , in which ordered solids are formed from disordered gaseous or liquid phases. In contrast, in endothermic reactions, heat is consumed from the environment.
This can occur by increasing the entropy of the system, often through the formation of gaseous reaction products, which have high entropy. Since the entropy increases with temperature, many endothermic reactions preferably take place at high temperatures.
On the contrary, many exothermic reactions such as crystallization occur at low temperatures. Changes in temperature can sometimes reverse the sign of the enthalpy of a reaction, as for the carbon monoxide reduction of molybdenum dioxide :.
This reaction to form carbon dioxide and molybdenum is endothermic at low temperatures, becoming less so with increasing temperature. Changes in temperature can also reverse the direction tendency of a reaction.
For example, the water gas shift reaction. The shift in reaction direction tendency occurs at K. Reactions can also be characterized by the internal energy which takes into account changes in the entropy, volume and chemical potential. The latter depends, among other things, on the activities of the involved substances. The speed at which reactions takes place is studied by reaction kinetics. The rate depends on various parameters, such as:.
Several theories allow calculating the reaction rates at the molecular level. This field is referred to as reaction dynamics.
The rate v of a first-order reaction , which could be disintegration of a substance A, is given by:. The rate of a first-order reaction depends only on the concentration and the properties of the involved substance, and the reaction itself can be described with the characteristic half-life. More than one time constant is needed when describing reactions of higher order. The temperature dependence of the rate constant usually follows the Arrhenius equation :.
One of the simplest models of reaction rate is the collision theory. More realistic models are tailored to a specific problem and include the transition state theory , the calculation of the potential energy surface , the Marcus theory and the Rice—Ramsperger—Kassel—Marcus RRKM theory. In a synthesis reaction, two or more simple substances combine to form a more complex substance.
These reactions are in the general form:. Two or more reactants yielding one product is another way to identify a synthesis reaction. One example of a synthesis reaction is the combination of iron and sulfur to form iron II sulfide :.