Chemical equations molar interpretation

To interpret a titration, we need the stoichiometric relation from the chemical equation for the reaction. This relation is used to write the mole ratio in the usual way. The only new step is to use the molarities of the solutions to convert between the moles of reactants and the volumes of... 

You can get the same kind of information from a balanced chemical equation. In Chapter 4, you learned how to classify chemical reactions and balance the chemical equations that describe them. In Chapters 5 and 6, you learned how chemists relate the number of particles in a substance to the amount of the substance in moles and grams. In this section, you will use your knowledge to interpret the information in a chemical equation, in terms of particles, moles, and mass. Try the following Express Lab to explore the molar relationships between products and reactants. 

Knowledge Required (1) The definition of molarity, M. (2) The interpretation of a balanced chemical equation. 

As we discussed in Section 3.4, the coefficients in a chemical equation can be interpreted as molar relationships as well as molecular relationships. So we can say that the equation shows that one mole of methane reacts with two moles of oxygen to produce one mole of carbon dioxide and two moles of water. From the chemical equation, we can write the following set of mole ratios ... 

You see from the preceding discussion that a balanced chemical equation relates the amounts of snbstances in a reaction. The coefficients in the equation can be given a molar interpretation, and using this interpretation you can, for example, calculate the moles of product obtained from any given moles of reactant. Also, yon can extend this type of calcnlation to answer questions about masses of reactants and products. 

A chemical equation may be interpreted in terms of moles of reactants and products, as well as in terms of molecules. Using this molar interpretation, you can convert from the mass of one substance in a chemical equation to the mass of another. The maximum amount of product from a reaction is determined by the limiting reactant, the reactant that is completely used up the other reactants are in excess. 

If you use the molar interpretation of a chemical equation, there is nothing unreasonable about using such coefficients as and . 

Thermochemical equation the chemical equation for a reaction (including phase labels) in which the equation is given a molar interpretation, and the enthalpy of reaction for these molar amounts is written directly after the equation. (6.4) Thermochemistry the study of the quantity of heat absorbed or evolved by chemical reactions, (p. 225)... 

The molar interpretation of a chemical equation involves reading the coefficients as the number of moles of the reactants and products. This is still a particulate-level explanation, but we are grouping the particles into counting units that make it easier to translate into a macroscopic-level interpretation. On the molar level, fractional coefficients are acceptable. H2(g) + V2 02(g) H20(g) can be read as one mole of... 

In Section 8.4 we introduced the three levels on which a chemical equation may be interpreted particulate, molar, and macroscopic. Let s briefly review the particulate and molar interpretations of an equation. Consider the equation... 

In this reaction, the number of silver atoms that reacts is twice the number of sulfur atoms. When 200 silver atoms react, 100 sulfur atoms are required. However, in the actual chemical reaction, many more atoms of both silver and sulfur would react. If we are dealing with molar amounts, then the coefficients in the equation can be interpreted in terms of moles. Thus, 2 mol of silver reacts with 1 mol of sulfur to produce 1 mol of Ag2S. Because the molar mass of each can be determined, the moles of Ag, S, and AgjS can also be stated in terms of mass in grams of each. Thus, 215.8 g of Ag and 32.1 g of S react to form 247.9 g of Ag2S. The total mass of the reactants (247.9 g) is equal to the mass of product (247.9 g). The various ways in which a chemical equation can be interpreted are seen in Table 9.1. 

Stoichiometry in Reactive Systems. The use of molar units is preferred in chemical process calculations since the stoichiometry of a chemical reaction is always interpreted in terms of the number of molecules or number of moles. A stoichiometric equation is a balanced representation that indicates the relative proportions in which the reactants and products partake in a given reaction. For example, the following stoichiometric equation represents the combustion of propane in oxygen ... 

The applicability of the multicomponent mass diffusion models to chemical reactor engineering is assessed in the following section. Emphasis is placed on the first principles in the derivation of the governing flux equations, the physical interpretations of the terms in the resulting models, the consistency with Pick s first law for binary systems, the relationships between the molar and mass based fluxes, and the consistent use of these multicomponent models describing non-ideal gas and liquid systems. 

The equilibrium constant for the complexation of cholesterol with Eu(fod)3 has been evaluated from measurements on a series of solutions at varying total concentrations but identical molar ratio. The same analysis provides values for the chemical shifts of protons in the uncomplexed steroid, and in the steroid-europium complex the latter value is not accessible by direct measurement, since the complex is always in equilibrium with the free steroid. The mathematical equations presented in this paper should be generally applicable. In another paper the validity of various procedures for interpreting lanthanide-induced shifts is explored comments on cholesterol are included. No one mathematical model at present available is considered to have general validity. 

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