Chemical equations decomposition reactions

What is needed now is some means for calculating e. To do this, it is useful to consider some component, H, which is formed only by Reaction I, which does not appear in the feed, and which has a stoichiometric coefficient of v/// = 1 for Reaction I and stoichiometric coefficients of zero for all other reactions. It is always possible to write the chemical equation for Reaction I so that a real product has a stoichiometric coefficient of +1. For example, the decomposition of ozone, 2O3 3O2, can be rewritten as 2/3O3 —> O2. However, you may prefer to maintain integer coefficients. Also, it is necessary that H not occur in the feed, that there is a unique H for each reaction, and that H participates only in the reaction that forms it. Think of H as a kind of chemical neutrino formed by the particular reaction. Since H participates only in Reaction I and does not occur in the feed, Equation (2.40) gives... 

Interpreting Chemical Equations Writing Chemical Equations Combination Reactions Decomposition Reactions Single-Replacement Reactions... 

The following plot shows how the partial pressures of reactant and products vary with time for the decomposition of compound A into compounds B and C. All three compounds are gases. Use this plot to do the following (a) Write a balanced chemical equation for the reaction, (h) Calculate the equilibrium constant for the reaction, (c) Calculate the value of Kc for the reaction at 25°C. 

Write the balanced chemical equation for (a) the thermal decomposition of potassium chlorate without a catalyst (b) the reaction of bromine with water (c) the reaction between sodium chloride and concentrated sulfuric acid, (d) Identify each reaction as a Bronsted acid—base, Lewis acid—base, or redox reaction. 

For the decomposition reaction of hydrogen iodide, the value of the exponent of [HI] in the rate law equation is the same as its molar coefficient in the balanced chemical equation. This is not always the case. The values of the exponents in a rate law equation must be determined by experiment... 

The order of a reaction cannot in general be predicted from the chemical equation a rate law is an empirical law. That is, a rate law is an experimentally determined characteristic of the reaction and cannot in general be written down from the stoichiometry of the chemical equation for the reaction. For instance, both the decomposition of N205 and that of N02 have a stoichiometric coefficient of 2 for the reactant, but one reaction is first order and the other is second order. The decomposition of ammonia also has a stoichiometric coefficient of 2 for the reactant, but its rate law is zero order. 

A reaction mechanism is a special kind of model unique to each reaction. For example, in the decomposition of ozone, 2 0,(g) - 3 02(g), we could imagine the reaction occurring in one step, when two O, molecules collide and rearrange their six atoms to form three 02 molecules (Fig. 13.22). Alternatively, we could imagine a mechanism involving two elementary reactions in the first step, an 03 molecule is energized by solar radiation and dissociates into an O atom and an 02 molecule. Then, in a second step, the O atom attacks another O, molecule to produce two more 02 molecules (Fig. 13.23). The O atom in the second mechanism is a reaction intermediate, a species that plays a role in a reaction but does not appear in the chemical equation for the overall reaction. 

Elementary reactions are summarized by chemical equations written without the state symbols. These equations show how individual atoms and molecules take part in the reaction, as shown in Figs. 13.22 and 13.23. For example, one proposed step in the decomposition of ozone is... 

Elementary reactions are classified on the basis of their molecularity, the number of molecules (or atoms) on the reactant side of the chemical equation for the elementary reaction. A unimolecular reaction is an elementary reaction that involves a single reactant molecule—for example, the unimolecular decomposition of ozone in the upper atmosphere ... 

The equilibrium constant Kc is the number obtained by multiplying the equilibrium concentrations of all the products and dividing by the product of the equilibrium concentrations of all the reactants, with the concentration of each substance raised to the power of its coefficient in the balanced chemical equation. No matter what the individual equilibrium concentrations may be in a particular experiment, the equilibrium constant for a reaction at a particular temperature always has the same value. Thus, the equilibrium equation for the decomposition reaction of N2O4 to give 2 N02 is... 

To decompose means to break apart. In a decomposition reaction, one reactant breaks apart and forms two or more products. When electricity is passed through water, the water will break down, or decompose, and produce hydrogen and oxygen. The chemical equation for this reaction is the opposite of the synthesis reaction that makes water ... 

Matter is conserved in chemical reactions The total mass of the products equals the total mass of the reactants. Chemical equations reflect this conservation. It is why chemical equations must be balanced. Atoms have mass, and the numbers of each kind of atom on each side of the equation must be the same. Coefficients, the numbers to the left of the formulas, are used to balance equations. Many equations can be balanced directly by simply adjusting the coefficients, as illustrated in the equations given above. Other equations are more difficult to balance, such as that for the decomposition of nitroglycerine (an explosive)... 

VU f Write the products for each decomposition reaction. Balance the chemical equation. 

For each reaction in Table B, write the appropriate balanced chemical equation for the double displacement reaction. Then write a balanced chemical equation for the decomposition reaction that leads to the formation of a gas and water. 

Classify each reaction as synthesis, decomposition, single displacement, double displacement, or combustion. Also, balance each chemical equation. 

In addition to balancing chemical equations, you can also classify the types of reactions that occur. There are four types of reactions synthesis, decomposition, single replacement, and double replacement. Explanations and examples of each are as follows ... 

Let s look at the electrolysis of water, a decomposition reaction. When water is subjected to an electric current, hydrogen gas and oxygen gas are formed. A chemical equation can be written to show this reaction ... 

An example of a chemically induced substitution reaction is represented by the halide removal in MnCl(CO)5 by AICI3 leading to the hexacarbonylmanganese(I) cation. The driving force of this reaction, carried ont at room temperature, is represented by the high affinity of aluminum for chloride. Similarly, the corresponding rhenium(I) derivative [Re(CO)6]AlCLi can be prepared. This complex has considerable stability in that it can be dissolved in water without prompt decomposition (equation 32). 

The decomposition reactions dealt with in these equations are strongly a function of the characteristics of the particular explosive charge. Particle size and surface area, the presence of chemical impurities, and other often uncontrollable factors all affect the decomposition reaction mechanism and hence its rate and thermochemical characteristics. Values o Ea, A//, and Z are not readily available in the literature, and often must be experimentally determined for the particular batch of explosives of interest. 

The rate equation in the thermal explosion theory is then expressed with the rate constant, Aa exp[- E/R II. alone. In other words, the rate of the exothermic decomposition reaction, in the early stages of the self-healing process, of a chemical of the TD type, including every gas-permeable oxidatively-heating substance, is thought, in the theory, to depend only on one variable, T, i.e., the temperature of the chemical, included in the rate constant. It is thus seen that the theory is in fact very simple by virtue of the /croth-ordcr assumption. 

It is obvious that the absence of the melting point is characteristic of the DTA curve of a powdery chemical of the TD type. That is, a powdery chemical of this type decomposes prior to melting. The self-heating behavior of a powdery chemical, such as 98 % O, a -azobis(isobutyronitrile) (AIBN), which decomposes explosively prior to any remarkable exothennic decomposition reaction, is also of the TD type, so that the F-K equation is applied to calculate its 1. When confined in the closed cell and subjected to the adiabatic selfheating test started from a in the range of 65 to 74 C, 2 cm of AIBN shows such a self-healing behavior, which is typical of liquid, or powdery, chemicals of the TD type, as exemplified in Fig. 15. 

Both liquid and powdery chemicals of the TD type are, however, the same to the effect that their exothermic decomposition reactions are accompanied with no phase transition. Therefore, when charged in the open-cup cell, or confined in the closed cell, in accordance with the self-heating property of the chemical, and subjected to the adiabatic self-heating test started from a r, 2 cm each of a liquid chemical, or a powdery chemical, of the TD type continues to self-heat over the at a very slow, but virtually constant, rate depending on the value of Ts in accordance with the Arrhenius equation, after its having been warmed up to the Ts. 

A chemical which is powdery at room temperature and shows a large interval between the two peaks of the DTA curve is, in principle, a liquid of the TD type. In case of a powdery chemical of this type, the melting is isolated, as a perfectly separate phase transition, from the exothermic decomposition reaction of the resultant liquid. In other words, the resultant liquid of this type decomposes exotliermically, independent of the melting process, so that the Semenov equation is applied to calculate the T. For instance, the DTA curve of MNTS is a case in point (see Fig. 12 in Section 3.3). 

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