Name: reaction bottlenecks in chemical kinetics
Uploaded: 2020-09-24T15:06:50.000Z
Duration: 3 min 8 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

NC K-12 Science Standard Course of Study

9-12

Chemistry

Matter and its Interactions

PS.Chm.5.1

Rate-Determining Steps

Most chemical reactions proceed in a multistep reaction mechanism. But how is a reaction mechanism determined?
Reaction mechanisms are hypothesized based on their balanced chemical equations and experimentally determined rate laws of each elementary step.
Each step has a specific reaction rate, rate constant, and activation energy. The slowest step is called the rate-determining step and influences the net reaction rate. It can be used to verify the rate law for the overall reaction and to validate a proposed reaction mechanism.
Consider the decomposition of nitrous oxide to nitrogen and oxygen. The experimentally determined rate law does not correspond to the rate expression of a single-step reaction, which is corroborated by the observed presence of oxygen atoms&#8212;a reaction intermediate.
Hence, a reaction mechanism is proposed where all steps cumulate to give the overall reaction.
First, the rate constants indicate that the first step is the rate-limiting step. It is the slowest, and thus influences the overall reaction rate. A rate law proposed from this step can be set equal to the overall rate law.
This proposed rate-law, directly derived from the molecular concentration of the elementary reactant, matches the experimental rate-law and verifies the predicted reaction mechanism.
However, many reactions start with a fast initial step followed by a rate-determining step. How can reaction mechanisms be proposed in such cases?
Consider the formation of nitrosyl bromide. The experimental rate law is second-order for nitric oxide and first-order for molecular bromine.
The first step is a fast equilibrium step with equal forward and reverse reaction rates, followed by the second rate-determining step, which contains a reaction intermediate. Consequently, the proposed rate law will hold the intermediate.
Therefore, a straightforward comparison between the proposed rate law, containing the reaction intermediate with an unknown concentration, and the experimental rate law, accommodating the starting reactants, is difficult.
However, assuming that the first step is in equilibrium, the intermediate concentration can be set equal to the reactants&#39; concentrations. Substituting this relationship into the proposed rate law, and combining the rate constants into an overall rate constant, generates an expression consistent with the experimental rate law.
Combining the elementary steps gives the overall balanced equation satisfying the second requirement for a reaction mechanism. Thus, the proposed two-step reaction mechanism of nitrosyl bromide formation is valid.

rate-determining steps

Relating Reaction Mechanisms
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to lane-closure. Like the bottleneck affecting the overall rate at which vehicles could travel, the slowest elementary step influences the net reaction rate.
Rate laws may be derived directly from the balanced chemical equations for elementary reactions. However, this is not the case for most chemical reactions, where balanced equations often represent the overall change in the chemical system, resulting from multistep reaction mechanisms. Therefore, the rate law must be determined from experimental data, and the reaction mechanism subsequently deduced from the rate law.
For instance, consider the reaction of NO2 and CO:
<img alt="Chromatography setup diagram; shows mobile/stationary phases; used for compound separation analysis." src="/files/ftp_upload/11382/11382_Equation_1.png" style="text-align: center; height: 50px;" data-altupdatedat="1754904545000" data-alt="Optical fiber modes diagram showing mode field distribution, key in photonics and telecommunications." />
The experimental rate law for this reaction at temperatures above 225 &#176;C is:
<img alt="Gibb's free energy formula; &#916;G=&#916;H&#8722;T&#916;S; thermodynamics equation diagram; chemical reactions analysis." src="/files/ftp_upload/11382/11382_Equation_2.png" style="text-align: center; height: 50px;" data-altupdatedat="1754904545000" data-alt="Eutectic phase diagram, temperature-composition axes, solid-liquid equilibrium, alloy example." />
According to the rate law, the reaction is first order with respect to NO2 and first-order with respect to CO. This is consistent with a single-step bimolecular mechanism, and it is possible that this reaction mechanism is valid for this chemical process at high temperatures.
However, at temperatures below 225 &#176;C, the reaction is described by a different rate law that is second order with respect to NO2:
<img alt="Force equilibrium diagram with parallel forces. Arrows indicate direction and magnitude of forces." src="/files/ftp_upload/11382/11382_Equation_3.png" style="text-align: center; height: 50px;" data-altupdatedat="1754904545000" data-alt="Static equilibrium diagram with forces &#931;Fx=0, &#931;Fy=0; mechanical system setup analysis." />
This rate law is not consistent with the single-step mechanism, but it is consistent with the following two-step mechanism:
<img alt="Physics static equilibrium, &#931;Fx=0, &#931;Fy=0, &#931;&#964;=0 diagram with forces and moments labeled for analysis." src="/files/ftp_upload/11382/11382_Equation_4.png" style="text-align: center; height: 70px;" data-altupdatedat="1754904545000" data-alt="Static equilibrium equation &#931;Fx=0, &#931;Fy=0 diagram, force vectors, balanced system, physics principles." />
The rate-determining (slower) step gives a rate law showing second-order dependence on the NO2 concentration, and the sum of the two elementary equations gives the overall net reaction.
In general, when the rate-determining (slower) step is the first step in the reaction mechanism, the rate law for the overall reaction is the same as the rate law for this step. However, when the rate-determining step is preceded by an elementary step involving a rapidly reversible reaction, the rate law for the overall reaction may be more difficult to derive, often due to the presence of reaction intermediates.
In such instances, the concept that a reversible reaction is at equilibrium when the rates of the forward and reverse processes are equal can be utilized.
For example, consider the reversible elementary reaction in which NO dimerizes to yield an intermediate species N2O2. When this reaction is at equilibrium:
<img alt="Gear mechanism diagram with annotated gears illustrating rotational motion and mechanical advantage." src="/files/ftp_upload/11382/11382_Equation_5.png" style="text-align: center; height: 115px;" data-altupdatedat="1754904545000" data-alt="Static equilibrium; &#931;Fx=0 diagram; balance of forces; mechanical analysis." />
This expression may be rearranged to express the concentration of the intermediate in terms of the reactant NO:
<img alt="Static equilibrium; &#931;Fx=0, &#931;Fy=0; force vectors diagram; physics analysis, mechanics study." src="/files/ftp_upload/11382/11382_Equation_6.png" style="text-align: center; height: 75px;" data-altupdatedat="1754904545000" data-alt="Polymeric structure, static equilibrium; chemical formula, diagram for educational research." />
This approach can be utilized in formulating rate laws for overall reactions when reaction intermediates are present.
Example of Deriving the Rate Law from a Reaction Mechanism
Consider a reaction between nitrogen monoxide and molecular chlorine, for which a two-step mechanism is proposed as shown:
<img alt="Carboxylic acid reaction mechanism, arrow depicting nucleophilic attack on carbonyl carbon diagram." src="/files/ftp_upload/11382/11382_Equation_7.png" style="text-align: center; height: 70px;" data-altupdatedat="1754904545000" data-alt="Static equilibrium diagram, &#931;Fx=0, beam balance, forces, torque analysis, equilibrium conditions." />
This mechanism can be used to derive the equation and predict the rate law for the overall reaction. Initially, by adding the two elementary reactions, the equation for the overall reaction is obtained.
<img alt="Static equilibrium equation &#931;Fx=0 &#931;Fy=0 diagram, depicting forces and equilibrium conditions." src="/files/ftp_upload/11382/11382_Equation_8.png" style="text-align: center; height: 110px;" data-altupdatedat="1754904545000" data-alt="Kirchhoff's law electrical circuit diagram, &#931;I=0, resistor voltage analysis, current direction arrows." />
To derive a rate law from this mechanism, the rates laws for each of the two elementary steps are written:
<img alt="Static equilibrium, &#931;Fx=0, &#931;Fy=0, torque diagram with force vectors, balancing method." src="/files/ftp_upload/11382/11382_Equation_9.png" style="text-align: center; height: 110px;" data-altupdatedat="1754904545000" data-alt="Chemical structure diagram of phosphatidylcholine, illustrating molecular formula and bonds." />
According to the proposed reaction mechanism Step 2 is the rate-determining step. Hence, the rate law for the overall reaction should be the same as the rate law for this elementary step. However, the rate law for Step 2 contains an intermediate species concentration, [NOCl2]. To modify this, the rate law of the first elementary step is used to derive an expression for the intermediate concentration in terms of reactant concentrations.
Assuming Step 1 is at equilibrium;
<img alt="Chemical reaction diagram of sulfuric acid and sodium hydroxide forming sodium sulfate and water." src="/files/ftp_upload/11382/11382_Equation_10.png" style="text-align: center; height: 130px;" data-altupdatedat="1754904545000" data-alt="static equilibrium, &#931;Fx=0, &#931;Fy=0, force balance diagram, educational physics concept, vector analysis" />
Substituting this expression into the rate law for Step 2 yields:
<img alt="Thermochromism process in leuco dye diagram; temperature-dependent color change mechanism." src="/files/ftp_upload/11382/11382_Equation_11v2.png" style="text-align: center; height: 70px;" data-altupdatedat="1754904545000" data-alt="Leucine amino acid structure diagram showing chemical formula C6H13NO2, educational use." />
This text is adapted from <a href="https://openstax.org/books/chemistry-2e/pages/12-6-reaction-mechanisms">Openstax, Chemistry 2e, Section 12.6: Reaction Mechanisms.</a>

Relating Reaction Mechanisms
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest ...

Education

JoVE Core

Chemical Kinetics

KEY TERMS AND CONCEPTS

reaction bottlenecks in chemical kinetics

Reaction bottlenecks help explain rate-determining steps in multistep reaction mechanisms. In a mechanism with several elementary steps, one step is often much slower than the others. That slowest step is called the rate-limiting step, or rate-determining step. A reaction cannot move faster than its slowest step, so this step controls the overall reaction rate.

The idea is like traffic on a four-lane freeway with one lane closed. Cars can only move as fast as the bottleneck allows. In the same way, the slowest elementary step sets the pace for the net chemical reaction.

Rate laws can be written directly from balanced equations for elementary reactions. For most reactions, though, the balanced equation shows only the overall change in the system. It does not show each step in the mechanism. For those cases, the rate law must be found from experimental data first, and the mechanism is then tested against that rate law.

The reaction between nitrogen dioxide and carbon monoxide shows this idea well. At temperatures above 225 °C, the experimental rate law is first order in NO2 and first order in CO. That matches a single-step bimolecular mechanism, so that mechanism may apply at high temperature. Below 225 °C, the rate law changes and becomes second order in NO2. That form does not fit the one-step idea, but it does fit a two-step mechanism with a slower first step.

When the rate-determining step is the first step in a mechanism, the overall rate law is the same as the rate law for that step. The rate law can be harder to build when a fast, reversible step happens first. In that case, reaction intermediates can appear. A reversible reaction is at equilibrium when the forward and reverse rates are equal. This idea can be used to rewrite the concentration of an intermediate, such as N2O2 formed when NO dimerizes, in terms of the reactant NO.

The same method works for a reaction between nitrogen monoxide and molecular chlorine. A two-step mechanism is proposed for this reaction, and the two elementary equations are added to get the overall reaction. Step 2 is the rate-determining step, so its rate law describes the overall reaction. Because that rate law includes the intermediate NOCl2, Step 1 is used to express the intermediate concentration in terms of the reactants. Treating Step 1 as an equilibrium step and substituting that result into the rate law for Step 2 gives the final rate law for the overall reaction.

Reaction Bottlenecks in Chemical Kinetics

reaction-bottlenecks-in-chemical-kinetics

reaction rate

Measuring Reaction Rates

Measuring reaction rates shows how fast reactants are used up or products are formed over time. The rate of reaction is the change in the amount of a reactant or product per unit time. Because of that, scientists measure how a property changes as the reaction proceeds and connect that change to reactant or product amounts. For reactions that make or use a gas, the rate can be followed by changes in volume or pressure. A rate expression is the mathematical way to write how concentration changes...

measuring reaction rates

Tracking Reaction Kinetics with Light and Pressure

Reaction kinetics can be tracked with polarimetry, spectrometry, and pressure measurements. These methods let scientists follow a reaction without disturbing the sample. They also help determine how reactant or product concentrations change over time. Polarimetry is used for optically active substances. These substances rotate the plane of polarized light, which is called optical rotation. The effect comes from molecular structure. Normal monochromatic light is unpolarized, but after it passes...

concentration and rate law

Reaction Order from Concentration

Reaction order from concentration shows how reactant amounts affect reaction rate. Rate laws, also called differential rate laws or rate equations, are mathematical expressions that connect reaction rate with the concentrations of reactants. For a generic reaction a A + b B → products, the rate law can be written using the reactant concentrations [A] and [B] and a rate constant k. In a rate law, k is the rate constant for one specific reaction at one specific temperature. The exponents m and n...

determining order of reaction

Finding Rate Law from Initial Rates

Rate laws connect the speed of a chemical reaction to the concentration of its reactants. The rate constant, k, and the reaction orders are not taken from the chemical equation. They are found experimentally by watching how the rate changes when the reactant concentrations change. One common way to do this is the method of initial rates. In this method, several trials are run with different starting concentrations. The measured rates are then compared to determine the reaction orders and,...

the integrated rate law: the dependence of concentration on time

the-integrated-rate-law-the-dependence-of-concentration-on-time

Reading Reaction Progress with Integrated Laws

Integrated rate laws connect reaction concentration to time. They help show how much reactant or product is present after a certain period. They can also help estimate how long a reaction must run to reach a given extent. A common use is finding how long radioactive material must be stored before its radioactivity drops to a safe level. These equations come from the differential rate law after it is integrated with respect to time. For a first-order reaction, where rate = k[A], the integrated...

half-life of a reaction

Reaction Half-Life in Kinetics

Reaction half-life is the time needed for half of a reactant to be consumed. After each half-life, half of the remaining reactant is used up. A hydrogen peroxide decomposition example shows this pattern clearly. The concentration drops from 1.000 M to 0.500 M in the first 6.00 hours, then to 0.250 M in the next 6.00 hours, and then to 0.125 M in the third period. Each later 6.00-hour interval removes half of what is left. For first-order reactions, the half-life does not depend on the reactant...

temperature dependence on reaction rate

Collision Theory and Reaction Speed

Collision theory explains why reaction speed depends on how particles collide. Atoms, molecules, or ions must come close together before they can react. The theory says the reaction rate depends on the collision rate, the orientation of the colliding species, and whether the collision has enough energy for bonds to change. A gas-phase reaction between carbon monoxide and oxygen shows why orientation matters. The molecules can collide in more than one way. If the oxygen side of carbon monoxide...

arrhenius plots

Determining Activation Energy from Temperature

The Arrhenius equation links activation energy and the rate constant, k, for chemical reactions. It is written as k = Ae−Ea/RT. In this equation, R is the ideal gas constant with a value of 8.314 J/mol·K, T is the temperature on the kelvin scale, Ea is the activation energy in J/mole, e is the constant 2.7183, and A is the frequency factor. The frequency factor depends on collision frequency and the orientation of reacting molecules. Experimental kinetic data can be used to find the activation...

reaction mechanisms

Elementary Steps in Reaction Mechanisms

Chemical reactions can happen in steps, and a balanced equation does not show the full path at the molecular level. A reaction mechanism, also called a reaction path, gives the step-by-step process that explains how reactants become products. The decomposition of ozone is one example of a reaction that can be described by a sequence of steps. Each step in a mechanism is an elementary reaction. These elementary reactions happen in order, and when they are added together, they give the balanced...

Reaction bottlenecks help explain rate-determining steps in multistep reaction mechanisms. In a mechanism with several elementary steps, one step is often much slower than the others. That slowest step is called the rate-limiting step, or rate-determining step. A reaction cannot move faster than its slowest step, so this step controls the overall reaction rate. The idea is like traffic on a four-lane freeway with one lane closed. Cars can only move as fast as the bottleneck allows. In the same...

catalysis

Catalyst Action in Reaction Rates

Catalysts change the rate of a chemical reaction by giving it a faster path. A catalyst increases reaction rate without being consumed during the process. Its effect is often explained with reaction mechanisms and energy diagrams. For an endothermic reaction, the reactants and products start and end at the same energies in both cases. The uncatalyzed path is a one-step mechanism with one transition state. The catalyzed path follows a different mechanism with two transition states and a lower...

enzymes

Enzyme Action and Inhibition

Enzymes are biological catalysts that speed up many reactions in living organisms. They help control cellular metabolism by lowering the activation energy needed for biochemical reactions. When activation energy drops, reaction rates can increase. Enzyme problems can also lead to serious disease. A genetic abnormality that causes G6PD, or glucose-6-phosphate dehydrogenase, deficiency can disrupt the pathway that supplies NADPH to cells. In red blood cells, this can reduce glutathione and...

key terms and concepts

Learn how the slowest step in a reaction mechanism controls reaction rate, how rate laws connect to experiments, and how intermediates help explain real examples.

Reaction Bottlenecks in Chemical Kinetics | JoVE K12

chemistry

JoVE Core Chemistry brings general chemistry concepts to life using concise and easy-to-understand animated video lessons. Plus, in the scientist-in-action videos, we demonstrate classical and original research experiments performed in today's laboratories worldwide.

Pennsylvania State Academic Standards

Physical Science

Chemical Reactions

3.2.9-12.D

3.2.9-12.E

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Interactions Of Matter

Chemical reactions

Virginia  Standards of Learning

HIgh School

CH.7

CH.7.e

Next Generation Science Standards

High School

Matter and Its Interactions

HS-PS1-2

HS-PS1-4

HS-PS1-5

HS-PS1-7

Florida Department of Education

SC.912.P.12

SC.912.P.12.12

new-york-state-science-learning-standards

New York State Science Learning Standards

HS. Chemical Reactions

HS-PS1-5.

Scientific Laws and Theories

Scientific Laws

In science, a law is defined as a concise, verbal or mathematical, statement that summarizes a vast number of experimental observations. ...

The Scientific Method

Chemistry is an empirical science. Scientists often pose questions to understand the chemistry in everyday life and seek answers to these questions. To ...

Classifying Matter by State

Chemistry is the study of matter and the changes it undergoes. Matter is anything that has mass and occupies space. Matter is all around us; the air, ...

Classifying Matter by Composition

Matter: Pure Substances and Mixtures
According to its composition, the matter can be classified into two broad categories &mdash; pure substances and ...

The Atomic Theory of Matter

The earliest recorded discussion of the basic structure of matter comes from ancient Greek philosophers. Leucippus and Democritus argued that all matter ...

Subatomic Particles

Dalton was only partially correct about the particles that make up matter. All matter is composed of atoms, and atoms are composed of three smaller ...

Elements: Chemical Symbols and Isotopes

A chemical symbol is an abbreviation used to indicate an element or an atom of an element. For example, the symbol for mercury is Hg. The same symbol is ...

Use models to explain how the scientific understanding of atomic structure has evolved.

PS.Chm.1.1

Radioactivity and Nuclear Equations

Nuclear chemistry is the study of reactions that involve changes in nuclear structure. The nucleus of an atom is composed of protons and, except for ...

Types of Radioactivity

The most common types of radioactivity are &#945; decay, &#946; decay, &#947; decay, neutron emission, and electron capture.
Alpha (&#945;) decay is the ...

Nuclear Stability

Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10&#8722;15 meters, a nucleus is ...

Nuclear Binding Energy

The difference between the calculated and experimentally measured masses is known as the mass defect of the atom. In the case of helium-4, the mass defect ...

Radioactive Decay and Radiometric Dating

Radioactivity is a spontaneous disintegration of an unstable nuclide and is a random process, as all the nuclei in the sample do not decay simultaneously. ...

Nuclear Fission

Many heavier elements with smaller binding energies per nucleon can decompose into more stable elements that have intermediate mass numbers and larger ...

Nuclear Power

Controlled nuclear fission reactions are used to generate electricity. Any nuclear reactor that produces power via the fission of uranium or plutonium by ...

Nuclear Fusion

The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process ...

Nuclear Transmutation

Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with ...

Use models to compare nuclear reactions including alpha decay, beta decay and gamma decay; nuclear fusion and nuclear fission.

PS.Chm.1.2

Atomic Orbitals

An atomic orbital represents the three-dimensional regions in an atom where an electron has the highest probability to reside. The radial distribution ...

The Pauli Exclusion Principle

The arrangement of electrons in the orbitals of an atom is called its electron configuration. We describe an electron configuration with a symbol that ...

The Energies of Atomic Orbitals

In an atom, the negatively charged electrons are attracted to the positively charged nucleus. In a multielectron atom, electron-electron repulsions are ...

The Aufbau Principle and Hund's Rule

To determine the electron configuration for any particular atom, we can build the structures in the order of atomic numbers. Beginning with hydrogen, and ...

electron-configuration-of-multielectron-atoms

Electron Configuration of Multielectron Atoms

The alkali metal sodium (atomic number 11) has one more electron than the neon atom. This electron must go into the lowest-energy subshell available, the ...

Use models to explain how electrons are distributed in atoms.

PS.Chm.1.3

Periodic Classification of the Elements

The periodic table arranges atoms based on increasing atomic number so that elements with the same chemical properties recur periodically. When their ...

The Periodic Table

As early chemists discovered more elements, they realized that various elements could be grouped by their similar chemical behaviors. One such grouping ...

Atomic Mass

Atoms &mdash; and the protons, neutrons, and electrons that compose them &mdash; are extremely small. For example, a carbon atom weighs less than 2 ...

Molar Mass

The identity of a substance is defined not only by the types of atoms or ions it contains but by the quantity of each type of atom or ion. For example, ...

Use the Periodic Table as a model to predict the relative properties of elements based on the pattern of valence electrons in the outermost energy levels of atoms.

PS.Chm.2.1

atomic-radii-and-effective-nuclear-charge

Atomic Radii and Effective Nuclear Charge

The elements in groups of the periodic table exhibit similar chemical behavior. This similarity occurs because the members of a group have the same number ...

Ionic Radii

Ionic radius is the measure used to describe the size of an ion. A cation always has fewer electrons and the same number of protons as the parent atom; it ...

Ionization Energy

The amount of energy required to remove the most loosely bound electron from a gaseous atom in its ground state is called its first ionization energy ...

Electron Affinity

The electron affinity (EA) is the energy change for adding an electron to a gaseous atom to form an anion (negative ion).



This process can be either ...

Construct an explanation to infer the atomic size, reactivity, electronegativity, and ionization energy of an element based on its position in the Periodic Table.

PS.Chm.2.2

Types of Chemical Bonds

Chemical bonding theories were pioneered by American chemist Gilbert&#xA0;N. Lewis. He developed a model called the Lewis model to explain the type and ...

Lewis Symbols and the Octet Rule

Chemical bonds are complex interactions between two or more atoms or ions, which reduce the potential energy of the molecule. Gilbert N. Lewis developed a ...

Ionic Bonding and Electron Transfer

Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence ...

The Born-Haber Cycle

Lattice Energy&#xA0;

An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a ...

trends-in-lattice-energy-ion-size-and-charge

Trends in Lattice Energy: Ion Size and Charge

An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure ...

Covalent Bonding and Lewis Structures

Compared to ionic bonds, which results from the transfer of electrons between metallic and nonmetallic atoms, covalent bonds result from the mutual ...

Electronegativity

Whether a bond is nonpolar or polar covalent is determined by a property of the bonding atoms called electronegativity.&#xA0;

Electronegativity values of ...

bond-polarity-dipole-moment-and-percent-ionic-character

Bond Polarity, Dipole Moment, and Percent Ionic Character

Bond Polarity

The absolute value of the difference in electronegativity (&Delta;EN) of two bonded atoms provides a rough measure of the polarity to be ...

lewis-structures-of-molecular-compounds-and-polyatomic-ions

Lewis Structures of Molecular Compounds and Polyatomic Ions

To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:


	Determine the ...

Resonance

The Lewis structure of a nitrite anion (NO2&minus;) may actually be drawn in two different ways, distinguished by the locations of the N-O and N=O ...

Formal Charges

In some cases, there are seemingly more than one valid Lewis structures for molecules and polyatomic ions. The concept of formal charges can be used to ...

Exceptions to the Octet Rule

Many covalent molecules have central atoms that do not have eight electrons in their Lewis structures. These molecules fall into three categories:


	...

Bond Energies and Bond Lengths

Stable molecules exist because covalent bonds hold the atoms together. The strength of a covalent bond is measured by the energy required to break it, ...

Analyze and interpret data to explain the mechanisms and properties of the two main types of intramolecular (ionic and covalent) bonds.

PS.Chm.3.1

molecular-comparison-of-gases-liquids-and-solids

Molecular Comparison of Gases, Liquids, and Solids

Particles in a solid are tightly packed together (fixed shape) and often arranged in a regular pattern; in a liquid, they are close together with no ...

Intermolecular vs Intramolecular Forces

Intermolecular forces (IMF) are electrostatic attractions arising from charge-charge interactions between molecules. The strength of the intermolecular ...

Intermolecular Forces

Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions ...

comparing-intermolecular-forces-melting-point-boiling-point

Comparing Intermolecular Forces: Melting Point, Boiling Point, and Miscibility

Intermolecular forces are attractive forces that exist between molecules. They dictate several bulk properties, such as melting points, boiling points, ...

surface-tension-capillary-action-and-viscosity

Surface Tension, Capillary Action, and Viscosity

Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded ...

Construct an explanation to summarize the influences intermolecular forces have on the properties of chemical compounds.

PS.Chm.3.2

Analyze the structure of atoms and isotopes.

Reaction Bottlenecks in Chemical Kinetics

Description

Transcript

Tags

More videos by Standards