gas evolution reaction

(noun)

a chemical process that produce a gas, such as oxygen or carbon dioxide

Related Terms

Examples of gas evolution reaction in the following topics:

  • Gas Evolution Reactions

    • A gas evolution reaction is a chemical process that produces a gas, such as oxygen or carbon dioxide.
    • A gas evolution reaction is a chemical process that produces a gas, such as oxygen or carbon dioxide.
    • The oxidation of a metal in acidic solution will yield a metal salt and hydrogen gas:
    • The oxidation of metals by strong acids is another common example of a gas evolution reaction.
    • Hydrochloric acid oxidizes zinc to produce an aqueous metal salt and hydrogen gas bubbles.

  • Substitution of the Hydroxyl Hydrogen

    • This is the procedure used in reactions 2 and 3.
    • This toxic and explosive gas is always used as an ether solution (bright yellow in color).
    • The reaction is easily followed by the evolution of nitrogen gas and the disappearance of the reagent's color.
    • The mechanisms of reactions 1 & 4 will be displayed in the second diagram below.
    • Examples of these reactions are displayed in the third diagram above.

  • Writing Chemical Equations

    • A chemical equation is the symbolic representation of a chemical reaction.
    • For example, a compound in the gas state would be indicated by (g), solid (s), liquid (l), and aqueous (aq).
    • Symbols are used to differentiate among different types of reactions.
    • If the reaction requires energy, it is often indicated above the arrow.
    • When a baking soda volcano is made by mixing vinegar (dilute aqueous acetic acid) and baking soda (sodium bicarbonate), the resulting evolution of gas occurs via the following reaction:

  • The Arndt-Eistert Reaction

    • When an ether solution of diazomethane is slowly added to a warm solution of the acid chloride, nitrogen evolution is observed and the chloromethyl ketone is the chief product.
    • One equivalent of diazomethane is required for this reaction.
    • The products are the diazo ketone and methyl chloride (a gas) from the reaction of diazomethane with HCl.
    • The first two examples are typical Arndt-Eistert reactions.
    • Reaction #3 is an example of such an alternative reaction.

  • Expressing the Equilibrium Constant of a Gas in Terms of Pressure

    • For gas-phase reactions, the equilibrium constant can be expressed in terms of partial pressures, and is given the designation KP.
    • Take the general gas-phase reaction:
    • In this expression, $\Delta n$ is a measure of the change in number of moles of gas in the reaction.
    • For instance, if a reaction produces three moles of gas, and consumes two moles of gas, then $\Delta n=(3-2)=1$.
    • Write the equilibrium expression, KP, in terms of the partial pressures of a gas-phase reaction

  • Metabolomics

    • GC-MS is a method that combines the features of gas-liquid chromatography and mass spectrometry to identify different substances within a test sample.
    • As sensitivity has improved with the evolution of higher magnetic field strengths and magic-angle spinning, NMR continues to be a leading analytical tool to investigate metabolism.
    • Further, it was noted that further progress in the field was in large part the result of addressing otherwise "irresolvable technical challenges" through technical evolution of mass spectrometry instrumentation.
    • The metabolome forms a large network of metabolic reactions, where outputs from one enzymatic chemical reaction are inputs to other chemical reactions.
    • Gas chromatography–mass spectrometry (GC-MS) is a method that combines the features of gas-liquid chromatography and mass spectrometry to identify different substances within a test sample.

  • Gas Stoichiometry

    • At standard temperature and pressure, one mole of any gas will occupy a volume of 22.4 L.
    • Stoichiometry is the quantitative study of the relative amounts of reactants and products in chemical reactions; gas stoichiometry involves chemical reactions that produce gases.
    • According to the above reaction, what volume of NO2(g) is produced from the combustion of 100 g of NH3(g), assuming the reaction takes place at standard temperature and pressure?
    • Shows how to use stoichiometry to convert from grams of a gas to liters of a gas.
    • Calculate volumes of gases consumed/produced in a reaction using gas stoichiometry.

  • Non-Ionic Reactions

    • With few exceptions, the multitude of reactions discussed in this and other introductory texts are classified as ionic reactions.
    • Here we shall consider two other classes of organic reactions: Free-Radical Reactions & Pericyclic Reactions.
    • One type of "free-radical reaction", alkane halogenation has already been described.
    • In contrast to ionic reactions, both free radical and pericyclic reactions may occur in the gas phase, as well as in solution in various solvents.
    • Also, these nonionic reactions are more tolerant of spectator functional groups than are many ionic reactions.

  • Irreversible Addition Reactions

    • Lithium aluminum hydride is by far the most reactive of the two compounds, reacting violently with water, alcohols and other acidic groups with the evolution of hydrogen gas.
    • Before leaving this topic it should be noted that diborane, B2H6, a gas that was used in ether solution to prepare alkyl boranes from alkenes, also reduces many carbonyl groups.
    • Consequently, selective reactions with substrates having both functional groups may not be possible.
    • Because of their ring strain, epoxides undergo many carbonyl-like reactions, as noted previously.
    • A common pattern, shown in the shaded box at the top, is observed in all these reactions.

  • Measuring Reaction Rates

    • The volume of oxygen produced can be measured using the gas syringe method.
    • The gas collects in the syringe, pushing out against the plunger.
    • The rate of a reaction that produces a gas can also be measured by calculating the mass loss as the gas forms and escapes from the reaction flask.
    • Note that it is not possible to collect the SO2 gas that is produced in the reaction because it is highly soluble in water.
    • In a reaction that produces a gas, the volume of the gas produced can be measured using the gas syringe method.