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https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Spectroscopy/Vibrational_Spectroscopy/Infrared_Spectroscopy/Interpreting_Infrared_Spectra/IR8._More_Complicated_IR_Spectra |
Sometimes more complicated heteroatomic functional groups, containing bonds to more than one heteroatom, have slightly different spectra. Carboxylic acids feature a hydroxyl group bonded to a carbonyl. Hexanoic acid, a carboxylic acid in a six-atom chain, is one example. If you look at the IR spectrum of hexanoi... | 666 | 144 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Book%3A_Quantum_States_of_Atoms_and_Molecules_(Zielinksi_et_al)/04%3A_Electronic_Spectroscopy_of_Cyanine_Dyes/4.05%3A_The_Transition_Dipole_Moment_and_Spectroscopic_Selection_Rules |
Once we know what energy a given transition would have, we can ask, “Which transitions between energy levels or states are possible?” In answering this question, we also will learn why the longer cyanine dye molecules have stronger absorptions, or larger absorption coefficients. Clearly the transitions cannot vi... | 7,385 | 145 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Basic_Principles_of_Organic_Chemistry_(Roberts_and_Caserio)/10%3A_Alkenes_and_Alkynes_I_-_Ionic_and_Radical_Addition_Reactions/10.05%3A_Orientation_in_Addition_to_Alkenes |
Addition of an unsymmetrical substance such as \(\ce{HX}\) to an unsymmetrical alkene theoretically can give two products: and Both products are seldom formed in equal amounts; in fact, one isomer usually is formed to the exclusion of the other. For example, the hydration of propene gives 2-propanol (not 1-p... | 8,768 | 146 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Basic_Principles_of_Organic_Chemistry_(Roberts_and_Caserio)/21%3A_Resonance_and_Molecular_Orbital_Methods/21.11%3A_Pericyclic_Reactions |
There are numerous reactions in organic chemistry that proceed through cyclic transition states. They may be classified generally as reactions. An important and familiar example is the Diels-Alder reaction, in which a conjugated diene cycloadds to an alkene or alkyne: This reaction has been described previousl... | 16,258 | 147 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/Atomic_and_Molecular_Properties/Intermolecular_Forces/Specific_Interactions/Hydrogen_Bonding |
A hydrogen bond is an intermolecular force (IMF) that forms a special type of dipole-dipole attraction when a hydrogen atom bonded to a strongly electronegative atom exists in the vicinity of another electronegative atom with a lone pair of electrons. Intermolecular forces (IMFs) occur between molecules... | 12,958 | 149 |
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Descriptive_Chemistry/Elements_Organized_by_Block/1_s-Block_Elements/Group__2_Elements%3A_The_Alkaline_Earth_Metals/Z056_Chemistry_of_Barium_(Z56)/Borax |
The name borax (disodium tetraborate) generally describes a number of closely related compounds with different amounts of crystal water: Borax forms soft colorless/white crystals which dissolve easily in water and which effloresce in dry air. Wikimedia Commons, user Aramgutang When heated to temperature... | 1,142 | 150 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Equilibria/Chemical_Equilibria/Calculating_An_Equilibrium_Concentrations/Effect_Of_Volume_Changes_On_Gas-phase_Equilibria |
states that when a system at equilibrium undergoes a change in temperature, volume, or amount of moles present in a reactant or product, the system will respond in order to reach equilibrium. Think of a system at equilibrium as a balanced scale (equal weights on both sides) and when one side gains more... | 1,307 | 151 |
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Coordination_Chemistry/Structure_and_Nomenclature_of_Coordination_Compounds/Isomers/Structural_Isomers%3A_Linkage_Isomerism_in_Transition_Metal_Complexes |
Linkage isomerism occurs with ligands that are capable of coordinating in more than one way. The best known cases involve the monodentate ligands: \(SCN^- / NCS^-\) and \(NO_2^- / ONO^-\). The only difference is what . The ligand(s) must have more than one donor atom, but bind to ion in only one place... | 1,957 | 152 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Supplemental_Modules_(Organic_Chemistry)/Reactions/Reactivity/Part_V%3A__Reactivity_in_Organic%2C_Biological_and_Inorganic_Chemistry_3/RO._Reduction_and_Oxidation/RO8._Electron_Transfer_Mechanisms%3A_Outer_Sphere |
How does an electron get from one metal to another? This might be a more difficult task than it seems. In biochemistry, an electron may need to be transfered a considerable distance. Often, when the transfer occurs between two metals, the metal ions may be constrained in particular binding sites within a protein... | 10,353 | 153 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Acids_and_Bases/Acid_Base_Reactions/The_Fall_of_the_Proton_-_Viewing_Acid_Base_Chemistry_from_a_Thermodynamic_Perspective |
An , being a proton donor, can only as an acid if there is a suitable present to accept the proton. What do we mean by "suitable'' in this context? Simply that a base, in order to accept a proton, must provide a lower-energy resting place for the proton. (We are actually referring to something called "free ... | 9,725 | 154 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Book%3A_Thermodynamics_and_Chemical_Equilibrium_(Ellgen)/06%3A_Equilibrium_States_and_Reversible_Processes/6.10%3A_Duhem's_Theorem_-_Specifying_Reversible_Change_in_A_Closed_System |
We view a chemical system as a collection of substances that occupies some volume. Let us consider a closed system whose volume is variable, and in which no work other than pressure–volume work is possible. If this system is undergoing a reversible change, it is at equilibrium, and it is in contact with its surr... | 11,722 | 155 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Kinetics/06%3A_Modeling_Reaction_Kinetics/6.02%3A_Temperature_Dependence_of_Reaction_Rates/6.2.01%3A_Activation_Parameters |
It seems intuitive that a reaction goes faster as the temperature is raised, as more reactant molecules have the energy needed to overcome the activation barrier to the reaction. The Arrhenius equation relates the reaction rate constant (k) and temperature. One of the forms of the Arrhenius equation is given bel... | 1,986 | 156 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Statistical_Mechanics/Statistical_Mechanical_Ensembles/The_Canonical_Ensemble/Heat_Capacity_within_the_Canonical_Ensemble |
The heat capacity is a coefficient that gives the amount of energy to raise the temperature of a substance by one degree Celsius. The heat capacity can also be described as the temperature derivative of the average energy. The constant volume heat capacity is defined by using the notation that E = U ... | 1,592 | 157 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Spectroscopy/Vibrational_Spectroscopy/Infrared_Spectroscopy/Interpreting_Infrared_Spectra/IR5._Carbon_Oxygen_Single_Bonds |
These bonds are pretty polar, so they show up strongly in IR spectroscopy. IR spectroscopy is therefore a good way to determine what heteroatom-containing functional groups are present in a molecule. Oxygen forms two bonds. An oxygen atom could be found in between two carbons, as in dibutyl ether, or between a c... | 1,593 | 158 |
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Descriptive_Chemistry/Elements_Organized_by_Block/2_p-Block_Elements/Group_13%3A_The_Boron_Family/Z013_Chemistry_of_Aluminum_(Z13)/Aluminium_Metallurgy |
This page starts by looking at the extraction of aluminum from its ore, bauxite, including some economic and environmental issues. It finishes by looking at some uses of aluminum. Aluminum is too high in the (reactivity series) to extract it from its ore using carbon reduction. The temperatures needed... | 4,727 | 159 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/Atomic_and_Molecular_Properties/Intermolecular_Forces/Specific_Interactions/Polarizability |
The term refers to the tendency of molecules to generate induced electric dipole moments when subjected to an electric field. It originates from the fact that nuclei and electrons are generally not fixed in space and that when molecules are subject to an electric field, the negatively charged electrons ... | 4,938 | 160 |
https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_Principles_of_Modern_Chemistry_(Oxtoby_et_al.)/Unit_2%3A_Chemical_Bonding_and_Structure/8%3A_Bonding_in_Transition_Metal_Compounds_and_Coordination_Complexes/8.3%3A_Introduction_to_Coordination_Chemistry |
A complex ion has a metal ion at its center with a number of other molecules or ions surrounding it. These can be considered to be attached to the central ion by (in some cases, the bonding is actually more complicated than that. The molecules or ions surrounding the central metal ion are called ligan... | 4,073 | 161 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Spectroscopy/Vibrational_Spectroscopy/Infrared_Spectroscopy/Interpreting_Infrared_Spectra/IR6._Carbon_Oxygen_Double_Bonds |
The largest class of oxygen-containing molecules is , which contain C=O bonds. A C=O stretch is normally easy to find in an IR spectrum, because it is very strong and shows up in a part of the spectrum that is not cluttered with other peaks. Examples of carbonyl compounds include 2-octanone, a ketone, and butan... | 1,164 | 162 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/Atomic_and_Molecular_Properties/Intermolecular_Forces/Specific_Interactions/Dipole_moments |
The intermolecular forces have important contribution in helping us to understand the interaction between atoms in same or different kind of molecules. The interaction can involve polar or non polar molecules and ions. There are three common and this module will focus more in-depth the interaction inv... | 3,718 | 163 |
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Descriptive_Chemistry/Elements_Organized_by_Block/2_p-Block_Elements/Group_13%3A_The_Boron_Family/Z005_Chemistry_of_Boron_(Z5)/Boranes_and_Borohydrides |
Boranes are compounds consisting of boron and hydrogen. They were investigated systematically by the german scientist Alfred Stock at the beginning of the 19th century. The most basic example is diborane (\(\ce{B2H6}\)), all boranes are electron-deficient compounds. For \(\ce{B2H6}\) usually 14 electron... | 2,264 | 164 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Basic_Principles_of_Organic_Chemistry_(Roberts_and_Caserio)/16%3A_Carbonyl_Compounds_I-_Aldehydes_and_Ketones._Addition_Reactions_of_the_Carbonyl_Group/16.02%3A_The_Carbonyl_Bond |
The carbonyl bond is both a strong bond and a reactive bond. The bond energy varies widely with structure, as we can see from the carbonyl bond energies in Table 16-1. Methanal has the weakest bond \(\left( 166 \: \text{kcal} \right)\) and carbon monoxide the strongest \(\left( 237.3 \: \text{kcal} \right)\). Ir... | 5,629 | 165 |
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Descriptive_Chemistry/Elements_Organized_by_Block/1_s-Block_Elements/Group__1%3A_The_Alkali_Metals/2Reactions_of_the_Group_1_Elements/Group_1_Compounds |
This page discusses a few compounds of the Group 1 elements (lithium, sodium, potassium, rubidium and cesium), including some information about the nitrates, carbonates, hydrogen carbonates and hydrides of the metals. Group 1 compounds are more resistant to heat than the corresponding compounds in Group 2. Lithi... | 7,825 | 167 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Spectroscopy/Electronic_Spectroscopy/Electronic_Spectroscopy_Basics/What_Causes_Molecules_to_Absorb_UV_and_Visible_Light |
This page explains what happens when organic compounds absorb UV or visible light, and why the wavelength of light absorbed varies from compound to compound. When we were talking about the various sorts of orbitals present in organic compounds on the introductory page (see above), you will have come across this ... | 16,723 | 168 |
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Descriptive_Chemistry/Elements_Organized_by_Block/3_d-Block_Elements/1b_Properties_of_Transition_Metals/Metallurgy/The_Extraction_of_Iron/Iron_Production |
The production of iron from its ore involves an carried out in a blast furnace. Iron ore is usually a mixture of iron and vast quantities of impurities such as sand and clay referred to as gangue. The iron found in iron ores are found in the form of iron oxides. As a result of these impurities, iron m... | 3,009 | 169 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Basic_Principles_of_Organic_Chemistry_(Roberts_and_Caserio)/13%3A_Polyfunctional_Compounds_Alkadienes_and_Approaches_to_Organic_Synthesis/13.03%3A_Cycloaddition_Reactions |
There are a variety of reactions whereby rings are formed through addition to double or triple bonds. An especially simple example is the addition of ethene to 1,3-butadiene to give cyclohexene: This is the prototype reaction, which has proved so valuable in synthesis that it won its discoverers, O. Diels and ... | 9,989 | 170 |
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Descriptive_Chemistry/Elements_Organized_by_Block/2_p-Block_Elements/Group_17%3A_The_Halogens/1Group_17%3A_General_Reactions/More_Reactions_of_Halogens |
This page describes reactions of the halogens that do not fall under the other categories in other pages in this section. All the reactions described here are redox reactions. The following examples illustrate the decrease in reactivity of the halogens down Group 7. Fluorine combines explosively with hydrogen ev... | 2,628 | 171 |
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Map%3A_Inorganic_Chemistry_(Housecroft)/06%3A_Structures_and_Energetics_of_Metallic_and_Ionic_solids/6.03%3A_The_Packing_of_Spheres_Model_Applied_to_the_Structures_of_Elements/6.3C%3A_Solid_Metallic_Elements |
A metal (from Greek μέταλλον métallon, "mine, quarry, metal") is a material (an element, compound, or alloy) that is typically hard, opaque, shiny, and has good electrical and thermal conductivity. Metals are generally - that is, they can be hammered or pressed permanently out of shape without breakin... | 4,809 | 172 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Book%3A_Thermodynamics_and_Chemical_Equilibrium_(Ellgen)/03%3A_Distributions_Probability_and_Expected_Values/3.01%3A_The_Distribution_Function_as_a_Summary_of_Experimental_Results |
In , we derive Boyle’s law from Newton’s laws using the assumption that all gas molecules move at the same speed at a given temperature. This is a poor assumption. Individual gas molecules actually have a wide range of velocities. In Chapter 4, we derive the Maxwell–Boltzmann distribution law for the distributi... | 3,575 | 174 |
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Coordination_Chemistry/Structure_and_Nomenclature_of_Coordination_Compounds/Isomers/Stereoisomers%3A_Geometric_Isomers_in_Transition_Metal_Complexes_II |
Geometric Isomers are isomers that differ in the arrangement of the ligands around the metal or the central atom. In other words, these isomers differ from each other based on where the ligands are placed in the coordinate compound. This will be much easier to understand as examples will be considered. ... | 4,646 | 175 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/States_of_Matter/Properties_of_Gases/Kinetic_Theory_of_Gases/Common_Ideal_Gas_Difficulties |
This page looks at the assumptions which are made in the Kinetic Theory about ideal gases, and takes an introductory look at the Ideal Gas Law: pV = nRT. There is no such thing as an ideal gas, of course, but many gases behave approximately as if they were ideal at ordinary working temperatures and pressures. Re... | 4,992 | 176 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Equilibria/Le_Chateliers_Principle/Effect_Of_Temperature_On_Equilibrium_Composition/Exothermic_Versus_Endothermic_And_K |
An reaction occurs when the temperature of a system increases due to the evolution of heat. This heat is released into the surroundings, resulting in an overall negative quantity for the heat of reaction (\(q_{rxn} < 0\)). An reaction occurs when the temperature of an isolated system decreases while t... | 4,379 | 177 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Radical_Reactions_of_Carbohydrates_(Binkley)/Radical_Reactions_of_Carbohydrates_II%3A_Radical_Reactions_of_Carbohydrates/Appendix_I%3A_Hydrogen-Atom_Donors/IV._Compounds_with_Phosphorous%E2%80%93Hydrogen_Bonds |
The search for less problematic hydrogen-atom transfers for use in the Barton-McCombie reaction has led to compounds with phosphorus–hydrogen bonds. These include dialkylphosphine oxides ( ), alkyl phosphites ( ), hypophosphorous acid ( ), and salts of hypophosphorous acid ( ) (Figure 2). All of these c... | 1,195 | 178 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Electronic_Structure_of_Atoms_and_Molecules/Electronic_Configurations/Case_Study%3A_Electron_Configuration_of_Mn_vs._Cu |
Transition metals consist of elements from the d-block found between the group IIa and the group IIb elements of the . A transition metal is an element that forms one or more stable ions which have incompletely filled d sub-orbitals. While these transition metals contain at most two electrons in their ... | 8,435 | 179 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Physical_Chemistry_(LibreTexts)/20%3A_Entropy_and_The_Second_Law_of_Thermodynamics/20.02%3A_Nonequilibrium_Isolated_Systems_Evolve_in_a_Direction_That_Increases_Their_Probability |
In spontaneous processes for an isolated system, there is a competition between minimizing the energy of the system and increasing the dispersal of energy within the system. If energy is constant, then the system will evolve to maximize energy dispersal. If energy dispersal is not a factor, the system w... | 2,387 | 180 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Basic_Principles_of_Organic_Chemistry_(Roberts_and_Caserio)/10%3A_Alkenes_and_Alkynes_I_-_Ionic_and_Radical_Addition_Reactions/10.04%3A_Electrophilic_Additions_to_Alkenes |
The reactions of alkanes discussed in are processes, which means that the bonds are made and broken through radical or atomic intermediates. In contrast, the \(S_\text{N}\) and \(E\) reactions of alkyl halides, considered in Chapter 8, involve heterolytic bond cleavage and ionic reagents or products. An espe... | 17,978 | 181 |
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In much the same fashion as the partial molar volume is defined, the is defined for compound \(i\) in a mixture: \[ \mu_i = \left( \dfrac{\partial G}{\partial n_i} \right) _{P,T,n_j\neq i} \label{eq1}\] The partial molar function is of particular importance and is called the . The chemical potential ... | 4,383 | 184 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Quantum_Mechanics/02._Fundamental_Concepts_of_Quantum_Mechanics/Deriving_the_Wien's_Displacement_Law_from_Planck's_Law |
Wien's displacement law states that the blackbody radiation curve for different temperatures peaks at a wavelength inversely proportional to the temperature. The shift of that peak is a direct consequence of the Planck radiation law which describes the spectral brightness of black body radiation as a fu... | 3,008 | 185 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/Atomic_and_Molecular_Properties/Intermolecular_Forces/Specific_Interactions/Dipole_Moment |
Let's go back to that first ion pair which was formed when the positive ion and the negative ion came together. If the electronegativities of the elements are sufficiently different (like an alkali metal and a halide), the charges on the paired ions will not change appreciably - there will be a full ele... | 2,321 | 186 |
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The hydrogen bond is really a special case of dipole forces. A hydrogen bond is the attractive force between the hydrogen attached to an electronegative atom of one molecule and an electronegative atom of a different molecule. Usually the electronegative atom is oxygen, nitrogen, or fluorine, which has ... | 2,281 | 187 |
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Two compounds that have the same formula and the same connectivity do not always have the same shape. There are two reasons why this may happen. In one case, the molecule may be flexible, so that it can twist into different shapes via rotation around individual sigma bonds. This phenomenon is called con... | 8,309 | 188 |
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Magnesium is a group two element and is the eighth most common element in the earth's crust. Magnesium is light, silvery-white, and tough. Like aluminum, it forms a thin layer around itself to help prevent itself from rusting when exposed to air. Fine particles of magnesium can also catch on fire when ... | 4,580 | 189 |
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Book3A_Bioinorganic_Chemistry_(Bertini_et_al.)/04%3A_Biological_and_Synthetic_Dioxygen_Carriers/4.07%3A_General_Aspects_of_the_Chemistry_of_Dioxygen |
Dioxygen has a rich redox chemistry that is not explicitly exploited in the oxygen carriers, but which is central to enzymes that coordinate and activate dioxygen for subsequent reaction with a substrate. On reduction of dioxygen by one electron, the superoxide anion radical O is formed. Concomitant wi... | 5,559 | 190 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Basic_Principles_of_Organic_Chemistry_(Roberts_and_Caserio)/13%3A_Polyfunctional_Compounds_Alkadienes_and_Approaches_to_Organic_Synthesis/13.02%3A_13-_or_Conjugated_Dienes._Electrophilic_and_Radical_Addition |
The reactions of 1,3-butadiene are reasonably typical of conjugated dienes. The compound undergoes the usual reactions of alkenes, such as catalytic hydrogenation or radical and polar additions, but it does so than most alkenes or dienes that have isolated double bonds. Furthermore, the products frequently are... | 2,724 | 191 |
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Strontium is a group 2 element that does not occur as a free element due to its extreme reactivity with oxygen and water. It occurs naturally only in compounds with other elements such as strontianite. It is softer than calcium and decomposes water more vigorously. It has a silver appearance but then tu... | 2,149 | 192 |
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Discovered by von Reichenstein in 1782, tellurium is a brittle metalloid that is relatively rare. It is named from the Latin tellus for "earth". Tellurium can be alloyed with some metals to increase their machinability and is a basic ingredient in the manufacture of blasting caps. Elemental tellurium is... | 6,211 | 193 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Quantum_Mechanics/02._Fundamental_Concepts_of_Quantum_Mechanics/Heisenberg's_Uncertainty_Principle/Commuting_Operators |
If two operators commute then both quantities can be measured at the same time, if not then there is a tradeoff in the accuracy in the measurement for one quantity vs. the other. Operators are commonly used to perform a specific mathematical operation on another function. The operation can be to take th... | 1,457 | 194 |
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Previously, we introduced Serpentinization, the geothermal processes that heat water up to 91°C (196°F) in the geothermal vents in the Atlantic Massif . A "Fly-in video" puts the formation into perspective. The Atlantis Massif rises ~14,000 feet above the surrounding seafloor and is formed by long-lived faulti... | 8,091 | 195 |
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This page discusses the tests for halide ions (fluoride, chloride, bromide and iodide) using silver nitrate and ammonia. This test is carried out in a solution of halide ions. The solution is acidified by adding dilute nitric acid. The nitric acid reacts with, and removes, other ions that might also form precipi... | 3,686 | 196 |
https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_ChemPRIME_(Moore_et_al.)/03%3A_Using_Chemical_Equations_in_Calculations/3.02%3A_Equations_and_Mass_Relationships/3.2.02%3A_Environment-_Atom_Efficiency_and_the_2006_Presidential_Green_Chemistry_Award |
The Presidential Green Chemistry Challenge Awards began in 1995 as an effort to recognize individuals and businesses for innovations in green chemistry. IWC replica Réplica de reloj Typically five awards are given each year, one in each of five categories: Academic, Small Business, Greener Synthetic Pathways, ... | 15,886 | 197 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Basic_Principles_of_Organic_Chemistry_(Roberts_and_Caserio)/10%3A_Alkenes_and_Alkynes_I_-_Ionic_and_Radical_Addition_Reactions/10.06%3A_Electrophilic_Addition_Reactions_of_Alkynes |
The alkynes behave in many ways as if they were doubly unsaturated alkenes. For example, bromine adds to ethyne in two stages - first to give -1,2-dibromoethene by antarafacial addition, and finally to give 1,1,2,2-tetrabromoethane: Likewise, anhydrous hydrogen fluoride adds first to give fluoroethene and ultim... | 2,094 | 199 |
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Write the Schrödinger equation for a particle in a two dimensional box with infinite potential barriers and adjacent sides of unequal length (a rectangle). Solve the equation by separating variables with a product function X(x)Y(y) to obtain the wavefunctions X(x) and Y(y) and energy eigenvalues. How many differ... | 4,119 | 200 |
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Intermolecular forces are forces between molecules. Depending on its strength, intermolecular forces cause the forming of three physical states: solid, liquid and gas. The physical properties of melting point, boiling point, vapor pressure, evaporation, viscosity, surface tension, and solubility are rel... | 5,018 | 202 |
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Selenium was discovered by Berzelius in 1818. It is named for the Greek for "moon", selene. Selenium can exist in multiple allotropes that are essentially different molecular forms of an element with varying physical properties. For example, one allotrope of selenium can be seen as an amphorous (“witho... | 3,677 | 203 |
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Another important feature of the The Lanthanide Contraction refers to the fact that the 5s and 5p orbitals penetrate the 4f sub-shell so the 4f orbital is not shielded from the increasing nuclear change, which causes the atomic radius of the atom to decrease. This decrease in size continues throughout t... | 4,714 | 205 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Nuclear_Chemistry/Applications_of_Nuclear_Chemistry/Radiation_in_Biology_and_Medicine%3A_Positron_Emission_Tomography |
Nuclear chemistry is the study of changes associated with the nuclei of atoms. Positron emission tomography (PET) is one of the beneficial real-life uses of nuclear chemistry. Simply, it is a handy instrument that physicians use to take images of an individual's body to determine if a person is at risk ... | 8,490 | 206 |
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Polonium was discovered in 1898 by Marie Curie and named for her native country of Poland. The discovery was made by extraction of the remaining radioactive components of pitchblende following the removal of uranium. There is only about 10 g per ton of ore! Current production for research purposes invo... | 838 | 207 |
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Hydrogen chloride (HCl) is a colorless gas which forms white fumes of hydrochloric acid when brought into contact with atmospheric humidity. Inhalation of the gas can cause severe burns of the nose, throat, and upper respiratory tract (which may lead to death in severe cases). Hydrogen chloride may also... | 844 | 208 |
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Hydrogen peroxide (H O ) is a viscous liquid (mp.: -0.89°C, bp.: 152.1°C, density: 1.448 g/cm at 20°C) that has strong oxidizing properties. It is commonly used (in concentrations typically around 5%) to bleach human hair, hence the phrases "peroxide blonde" and "bottle blonde". It burns the skin upon ... | 1,625 | 209 |
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This page explains what a transition metal is in terms of its electronic structure, and then goes on to look at the general features of transition metal chemistry. These include variable oxidation state (oxidation number), complex ion formation, colored ions, and catalytic activity. The terms transition... | 8,838 | 210 |
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In this section we examine how the results of the various approximation methods considered in this chapter can be used to understand and predict the physical properties of multi-electron atoms. Our results include total electronic energies, orbital energies and single-electron wavefunctions that describe the spa... | 814 | 211 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Basic_Principles_of_Organic_Chemistry_(Roberts_and_Caserio)/13%3A_Polyfunctional_Compounds_Alkadienes_and_Approaches_to_Organic_Synthesis/13.03%3A_Cycloaddition_Reactions |
There are a variety of reactions whereby rings are formed through addition to double or triple bonds. An especially simple example is the addition of ethene to 1,3-butadiene to give cyclohexene: This is the prototype reaction, which has proved so valuable in synthesis that it won its discoverers, O. Diels and ... | 9,989 | 213 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Basic_Principles_of_Organic_Chemistry_(Roberts_and_Caserio)/10%3A_Alkenes_and_Alkynes_I_-_Ionic_and_Radical_Addition_Reactions/10.04%3A_Electrophilic_Additions_to_Alkenes |
The reactions of alkanes discussed in are processes, which means that the bonds are made and broken through radical or atomic intermediates. In contrast, the \(S_\text{N}\) and \(E\) reactions of alkyl halides, considered in Chapter 8, involve heterolytic bond cleavage and ionic reagents or products. An espe... | 17,978 | 214 |
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There are many factors to be considered such as covalent character and electron-electron interactions in ionic solids. But for simplicity, let us consider the ionic solids as a collection of positive and negative ions. In this simple view, appropriate number of cations and anions come together to form a... | 4,950 | 215 |
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As we shall see, the two heaviest members of each group usually exhibit substantial similarities in chemical behavior and are quite different from the lightest member. As shown in Table \(\Page {1}\), the observed trends in the properties of the group 3 elements are similar to those of groups 1 and 2. D... | 34,993 | 216 |
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In our survey of the dioxygen chemistry of iron and copper species in earlier subsections, three general functions for the protein matrix became apparent: provision of ligand(s) in an appropriate stereochemistry; protection of the metal-dioxygen moiety from oxidation and competitive ligands; and modulat... | 3,470 | 217 |
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In our survey of the dioxygen chemistry of iron and copper species in earlier subsections, three general functions for the protein matrix became apparent: provision of ligand(s) in an appropriate stereochemistry; protection of the metal-dioxygen moiety from oxidation and competitive ligands; and modulat... | 3,470 | 218 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/Solutions_and_Mixtures/Solution_Basics/Intermolecular_Forces_In_Mixtures_And_Solutions |
Some forces that interact within pure liquids are also present during mixtures and solutions. Forces such as Cohesive as well as Adhesive forces still apply to mixtures; however, more importantly we focus on the interaction between different molecules. Why is oil only soluble in benzene and not water? W... | 5,513 | 219 |
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Most alkenes react readily with ozone \(\left( \ce{O_3} \right)\), even at low temperatures, to yield cyclic peroxidic derivatives known as . For example, These substances, like most compounds with peroxide \(\left( \ce{O-O} \right)\) bonds, may explode violently and unpredictably. Therefore ozonizations must b... | 5,997 | 220 |
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states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the gases in the mixture. the different molecules in a mixture of gases are so far apart that they act independently; they do not react with each other. The pressure of an ideal gas is determine... | 4,004 | 222 |
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Ligands can be further characterized as monodentate, bidentate, tridentate etc. where the concept of teeth is introduced. Monodentate ligands bind through only one donor atom. Monodentate means "one-toothed." The halides, phosphines, ammonia and amines seen previously are monodentate ligands. Bidentat... | 6,190 | 223 |
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In this chapter we used a very simple model called the particle-in-a-box model or the infinite-potential-well model to obtain very crude approximate wavefunctions for pi electrons in cyanine dye molecules. With the particle in the box model, we can estimate the wavelengths at which the peaks occur in the absorpt... | 3,040 | 224 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Physical_Chemistry_(LibreTexts)/20%3A_Entropy_and_The_Second_Law_of_Thermodynamics/20.09%3A_The_Statistical_Definition_of_Entropy_is_Analogous_to_the_Thermodynamic_Definition |
We learned earlier in 20-5 that entropy, \(S\), is related to the number of microstates, \(W\), in an ensemble with \(A\) systems: \[S_{ensemble}=k_B \ln{W} \label{eq1} \] and \[W=\frac{A!}{\prod_j{a_j}!} \label{eq2} \] Combining Equations \ref{eq1} and \ref{eq2} to get: \[\begin{split} S_{ens... | 1,924 | 225 |
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The transition metals, groups 3–12 in the periodic table, are generally characterized by partially filled d subshells in the free elements or their cations. (Although the metals of group 12 do not have partially filled d shells, their chemistry is similar in many ways to that of the preceding groups, an... | 12,020 | 226 |
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This page takes an introductory look at two areas of bonding theory needed for a proper understanding of how organic compounds absorb some of the UV or visible light that passes through them. It looks simply at anti-bonding orbitals, and what is meant by conjugation in compounds and how it contributes to the del... | 13,327 | 227 |
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Electron configuration describes the distribution of electrons among different orbitals (including shells and subshells) within atoms and molecules. here are four principle (s, p, d, and f) which are filled according to the energy level and valence electrons of the element. All four orbitals can hold ... | 5,536 | 228 |
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Sulfur is a chemical element that is represented with the chemical symbol "S" and the atomic number 16 on the periodic table. Because it is 0.0384% of the Earth's crust, sulfur is the seventeenth most abundant element following strontium. Sulfur also takes on many forms, which include elemental sulfur, ... | 11,387 | 229 |
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In chemical thermodynamics, activity (symbol a) is a measure of the “effective concentration” of a species in a mixture, in the sense that the species' chemical potential depends on the activity of a real solution in the same way that it would depend on concentration for an ideal solution. By convention... | 17,458 | 232 |
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Chemists are committed to the idea that a balanced chemical equation such as \[2 Fe + O_2 \rightarrow 2 FeO \label{1} \] not only tells how many atoms or molecules of each kind are involved in a reaction, it also indicates the of each substance that is involved. Equation (1) says that 1 Fe atom can react with ... | 12,354 | 233 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Radical_Reactions_of_Carbohydrates_(Binkley)/Radical_Reactions_of_Carbohydrates_II%3A_Radical_Reactions_of_Carbohydrates/Appendix_I%3A_Hydrogen-Atom_Donors/VI._Compounds_with_Carbon%E2%80%93Hydrogen_Bonds |
Few compounds in which a carbon–hydrogen bond must serve as the hydrogen-atom source are reactive enough to function as hydrogen-atom transfers in radical reactions of carbohydrates. The reason for this is that when less reactive donors are used, other reactions become competitive. Even compounds with quite rea... | 3,202 | 234 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Book%3A_Thermodynamics_and_Chemical_Equilibrium_(Ellgen)/03%3A_Distributions_Probability_and_Expected_Values/3.10%3A_Statistics_-_the_Mean_and_the_Variance_of_a_Distribution |
There are two important statistics associated with any probability distribution, the of a distribution and the of a distribution. The mean is defined as the expected value of the random variable itself. The Greek letter \(\mu\) is usually used to represent the mean. If \(f\left(u\right)\) is the cumulative pro... | 5,814 | 236 |
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Aluminum oxide, with the chemical formula \(Al_2O_3\), is an amphoteric oxide and is commonly referred to as alumina. Corundum (α-aluminum oxide), emery, sapphire, amethyst, topaz, as well as many other names are reflecting its widespread occurrence in nature and industry. Corundum is the most common na... | 2,840 | 237 |
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We can use these ideas to create a plot that approximates the cumulative probability distribution function given any set of \(N\) measurements of a random variable \(u\). To do so, we put the \(u_i\) values found in our \(N\) measurements in order from smallest to largest. We label the ordered values \(u_1\), \(... | 4,862 | 238 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Statistical_Mechanics/Fundamentals_of_Statistical_Mechanics/09._Classical_and_quantum_dynamics_of_density_matrices |
Statistical mechanics makes the connection between macroscopic dynamics and equilibriums states based on microscopic dynamics. For example, while thermodynamics can manipulate equations of state and fundamental relations, it cannot be used to derive them. Statistical mechanics can derive such equations ... | 19,595 | 241 |
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This page describes how to perform a flame test for a range of metal ions, and briefly discusses how the flame color arises. Flame tests are used to identify the presence of a relatively small number of metal ions in a compound. Not all metal ions give flame colors. For compounds, flame tests are usua... | 3,955 | 242 |
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Entropy is a state function, so we can calculate values for a process using any path. This allows us to calculate the entropy change of a chemical reaction using standard entropies. Specifically, we sum the entropies of the products and subtract the entropies of the reactions: \[\Delta_{rxn}S^\circ = \s... | 915 | 244 |
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A change is said to occur reversibly when it can be carried out in a series of infinitesimal steps, each one of which can be undone by making a similarly minute change to the conditions that bring the change about. For example, the reversible expansion of a gas can be achieved by reducing the external p... | 19,234 | 245 |
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In the presence of dioxygen, iron(II) species are readily oxidized to iron(III) species. In the presence of water, iron(III) species frequently associate into \(\mu\)-oxodiiron(III) dimers. For iron(II)-porphyrin complexes this process may take only milliseconds at room temperature. The following mechan... | 10,210 | 246 |
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All organic and biological compounds contain carbon and hydrogen, usually with various other elements as well. Hydrocarbons are compounds containing only carbon and hydrogen, but no other types of atoms. Since all organic compounds contain carbon and hydrogen, looking at hydrocarbon spectra will tell us what pea... | 1,275 | 247 |
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The biological properties of molecules depends strongly on their polarity, because and play a large part in "noncovalent attractions" between molecules. Noncovalent attractions which are responsible for the DNA double helix, and antibody-antigen bonding can be understood in terms of alone, but sometimes th... | 8,540 | 248 |
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To understand ionic reactions, we need to be able to recognize whether a particular reagent will act to or to . Reagents that acquire an electron pair in chemical reactions are said to be ("electron-loving"). We can picture this in a general way as a heterolytic bond breaking of compound \(X:Y\) by an elect... | 5,152 | 249 |
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Symmetrical reagents do not differentiate between the members of a pair of enantiomers for the same reason that an ordinary sock fits equally well on a right foot as on a left foot. However, asymmetric or chiral reagents can differentiate between enantiomers, especially by having at least some difference in reac... | 3,292 | 250 |
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Recall that the entropy of a system, \(S\), can be calculated if the partition function, \(Q\), is known: \[S=\frac{U}{T}+k_B \ln{Q} \nonumber \] where \(Q\) is: \[Q=\sum_j{e^{-\frac{E_j}{kT}}} \nonumber \] The internal energy of the system can also be calculated from the partition function: \[U=k_BT^2\... | 1,384 | 251 |
https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_ChemPRIME_(Moore_et_al.)/02%3A_Atoms_Molecules_and_Chemical_Reactions/2.04%3A_Macroscopic_and_Microscopic_Views_of_a_Chemical_Reaction/2.4.01%3A_Foods-_The_Mineral_Nutrients_Potassium_and_Iodine |
In a previous section on we looked at essential minerals that are sometimes called , but are really only usable to our bodies when they are supplied as . Both potassium and iodine are essential nutrients, but each must be supplied in a compound if it is to be of any use (let alone nontoxic) to the body. Iodi... | 3,913 | 252 |
https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_Principles_of_Modern_Chemistry_(Oxtoby_et_al.)/Unit_5%3A_Rates_of_Chemical_and_Physical_Processes/20%3A_Molecular_Spectroscopy_and_Photochemistry/20.1%3A_General_Aspects_of_Molecular_Spectroscopy |
Electromagnetic radiation, as you may recall from a previous chemistry or physics class, is composed of electrical and magnetic waves which oscillate on perpendicular planes. Visible light is electromagnetic radiation. So are the gamma rays that are emitted by spent nuclear fuel, the x-rays that a docto... | 5,115 | 253 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Book%3A_Thermodynamics_and_Chemical_Equilibrium_(Ellgen)/03%3A_Distributions_Probability_and_Expected_Values/3.11%3A_The_Variance_of_the_Average-_The_Central_Limit_Theorem |
The establishes very important relationships between the statistics for two distributions that are related in a particular way. It enables us to understand some important features of physical systems. The central limit theorem concerns the distribution of averages. If we have some original distribution and sam... | 1,784 | 254 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Acids_and_Bases/Acids_and_Bases_in_Aqueous_Solutions/The_pH_Scale/Temperature_Dependence_of_the_pH_of_pure_Water |
The formation of hydrogen ions (hydroxonium ions) and hydroxide ions from water is an endothermic process. Using the simpler version of the equilibrium: \[ H_2O_{(l)} \rightleftharpoons H^+_{(aq)} + OH^-_{(aq)}\] Hence, the forward reaction, as written, "absorbs heat". According to , if you make a chan... | 2,197 | 255 |
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Basic_Principles_of_Organic_Chemistry_(Roberts_and_Caserio)/04%3A_Alkanes/4.05%3A_Halogenation_of_Alkanes._Energies_and_Rates_of_Reactions |
The economies of the highly industrialized nations of the world are based in large part on energy and chemicals produced from petroleum. Although the most important and versatile intermediates for conversion of petroleum to chemicals are compounds with double or triple bonds, it also is possible to prepare many ... | 32,267 | 257 |
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Descriptive_Chemistry/Elements_Organized_by_Block/2_p-Block_Elements/Group_13%3A_The_Boron_Family/1Group_13%3A_General_Properties_and_Reactions |
The boron family contains the semi-metal (B) and metals (Al), (Ga), (In), and (Tl). These elements are found in Group 13 (XIII) of the p block in the . Aluminum, gallium, indium, and thallium are metallic. They each have three electrons in their outermost shell (a full s orbital and one electron i... | 6,683 | 258 |
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Descriptive_Chemistry/Elements_Organized_by_Block/3_d-Block_Elements/Group_07%3A_Transition_Metals/Chemistry_of_Manganese/Chemistry_of_Manganese |
This page looks at some aspects of manganese chemistry. It includes: two simple reactions of manganese(II) ions in solution (summarized from elsewhere on the site), and the use of potassium manganate(VII) (potassium permanganate) as an oxidizing agent - including its use in titrations. The simplest ion that mang... | 4,336 | 259 |
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/Solutions_and_Mixtures/Ideal_Solutions/Dissolving_Gases_In_Liquids%2C_Henry's_Law |
Henry's law is one of the gas laws formulated by William Henry in 1803 and states: "At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid." An equivalent way of... | 2,457 | 260 |
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