Conversions chemical equation

Temperature units/conversions Periodic table Basic atomic structure Quantum mechanical model Atomic number and isotopes Atoms, molecules, and moles Unit conversions Chemical equations Stoichiometric calculations Week 3 Atmospheric chemistry... 

This rule allows you to find AH corresponding to any desired amount of reactant or product. To do this, you follow the conversion-factor approach used in Chapter 3 with ordinary chemical equations. Consider, for example,... 

A chemical equation tells us the relations between the amounts (in moles) of each reactant and product. By using the molar masses as conversion factors, we can express these relations in terms of masses. 

Fig. 8-1 The conversion of moles of one reagent to moles of another, using a ratio of the coefficients of the balanced chemical equation as a factor label...

The balanced equation expresses quantities in moles, but it is seldom possible to measure out quantities in moles directly. If the quantities given or required are expressed in other units, it is necessary to convert them to moles before using the factors of the balanced chemical equation. Conversion of mass to moles and vice versa was considered in Sec. 4.5. Here we will use that knowledge first to calculate the number of moles of reactant or product, and then use that value to calculate the number of moles of other reactant or product. 

The pivotal conversion is from one substance to another, in moles with the balanced chemical equation providing the conversion factor. 

The conversion factor is obtained from the balanced chemical equation. 

The balanced chemical equation provides a conversion factor between the two compounds. 

QA First, determine the mass of iron that has reacted as Fe2+ with the titrant. The balanced chemical equation provides the essential conversion factor. 

This balanced equation can be read as 4 iron atoms react with 3 oxygen molecules to produce 2 iron(III) oxide units. However, the coefficients can stand not only for the number of atoms or molecules (microscopic level) but they can also stand for the number of moles of reactants or products. So the equation can also be read as 4 mol of iron react with 3 mol of oxygen to produce 2 mol ofiron(III) oxide. In addition, if we know the number of moles, the number of grams or molecules may be calculated. This is stoichiometry, the calculation of the amount (mass, moles, particles) of one substance in the chemical equation from another. The coefficients in the balanced chemical equation define the mathematical relationship between the reactants and products and allow the conversion from moles of one chemical species in the reaction to another. 

You should be very careful when working problems involving gases and one or more other phases. The gas laws can only give direct information about gases. This is why there is a mole ratio conversion (from the balanced chemical equation) in this example to convert from the solid (KCI03) to the gas (02). 

The potential of these reactions for methane production can be compared in terms of theoretical yields and heat recovery efficiencies. Theoretical methane yield is defined by the chemical equations. Theoretical heat recovery efficiency is defined as the percent of the higher heating value of the coal which is recovered in the form of methane product. These idealized parameters provide a measure of the ultimate capability of conversion systems and are useful for evaluating actual conversion processes. 

Conversely, lower pressures favor formation of styrene. So the logic is that steam mixed with the EB permits cracking the hydrogen off at lower pressure and favors the styrene staying cracked. (You may have noticed the chemical equation in Figure 8—6 has arrows going both directions. Thats the chemists notation for this reversibility.)... 

Example 13.2 Write chemical equations for the following conversions (i) CHg-CH -Cl into CHg-CH -CH -NH ... 

C 0 and H O, unavoidable by-products of alcohols synthesis. Considering chemical reactions of table H, water and carbon dioxide appear as equiva-lentby-products due to shift conversion equilibrium, equation (1). Most other low temperature alcohol synthesis catalysts have a rather high shift activity as well. CO removal fhom reacted syngas of synthesis loop, before recycling to reactor, leads to a significant decrease of water formation which, in turn, results in a lower water content in the raw alcohols, leading to simplified fhactionation-dehydration processes. 

After you understand how to interpret chemical symbols, the names of compounds (see Chapter 6), and the symbols in Table 8-1, you can understand almost anything. You re equipped, for example, to decode a chemical equation into an English sentence describing a reaction. Conversely, you can translate an English sentence into the chemical equation it describes. When you re fluent in this language, you regrettably won t be able to talk to the animals you will, however, be able to describe their metabolism in great detail. 

The balanced chemical equation for a reaction is used to set up the conversion factor from one substance to another and that conversion factor, the mole ratio for the reaction, is applied to the moles given to calculate the moles required. 

The sequence of conversions in Figure 18.20 is used to calculate the mass or volume of product produced by passing a known current through a cell for a fixed period of time. The key is to think of the electrons as a "reactant" in a balanced chemical equation and then to proceed as with any other stoichiometry problem. Worked Example 18.10 illustrates the calculations. Alternatively, we can calculate the current (or time) required to produce a given amount of product by working through the sequence in Figure 18.20 in the reverse direction, as shown in Worked Example 18.11. 

Stoichiometry is the series of calculations on the basis of formulas and chemical equations and will be covered in Chapter 4. The use of conversion factors is common even when the relative proportions are not fixed by a chemical formula. Consider a silver alloy used for jewelry production. (Alloys are mixtures of metals and, as mixtures, may be produced in differing ratios of the metals.) A particular alloy contains 86 percent silver. Factors based on this composition, such as... 

The International Union of Biochemistry has recommended that enzymes have three names, namely a systematic name, which shows the reaction being catalysed and the type of reaction based on the classification in Table A7.1, a recommended trivial name and a four figure Enzyme Commission code (EC code). Nearly all systematic and trivial enzyme names have the suffix -ase. Systematic names show, often in semi-chemical equation form, the conversion the enzyme promotes and the class of the enzyme. Trivial names are usually based on the function of the enzyme but may also include or be based on the name of the substrate. However, some trivial names in current use are historical and bear no relationship to the action of the enzyme or its substrate, for example, pepsin and trypsin are the names commonly used for two enzymes that catalyse the breakdown of proteins during digestion. The Enzyme Commission s code is unique for each enzyme. It is based on the classification in Table A7.1 but further subdivides each class of enzyme according to how it functions. The full code is... 

Write the two chemical equations that describe the conversion of magnesium into magnesium oxide. 

So that the chemical potential multiplied by the amount of the substance present gives the free energy of a pure material, conversely, dividing equation (27.5) through by m ... 

The most important step to all of these calculations is the use of a value known as the mole ratio. The mole ratio is the ratio of moles of one substance to moles of second substance. It is determined by the ratios of the coefficients from the balanced chemical equation. The mole ratio is used in all conversions since it allows you to switch from values that describe the given substances to values that describe the unknown substance. To facilitate this process, there is another chart, Figure 12.2, that provides guidelines for solving most problems. In this first type of calculation, we will use the mole ratio to convert from units of moles of the given substance to moles of the unknown substance. We re going to omit the states of the reactants and products so that you can focus your attention on the coefficients. 

Consider the reaction of phosphorus with chlorine as shown in the previous equation. Of course, the chemist is not required to place exactly 2 mol of P and 3 mol of CI2 in a reaction flask. The equation gives the reacting ratio. Ratios of coefficients from balanced chemical equations can be used as conversion factors for solving problems. 

The coefficient in the balanced chemical equation is not used in conversions between grams and moles of a substance. 

However, this simple chemical equation conceals a more complicated sequence of events in which the reactants undergo various transformations before the product is formed. These may be summarized in a Born-Haber thermodynamic cycle (Figure 3.1). The first stage of the reaction process is the conversion of M and E into gaseous state atoms, requiring an enthalpy of atomization of A// j(M), and, if E is a solid or liquid, the enthalpy of vaporization, of E or... 

The coefficients in a balanced chemical equation show the relative numbers of moles of the substances in the reaction. As a result, you can use the coefficients in conversion factors called mole ratios. Mole ratios bridge the gap and can convert from moles of one substance to moles of another, as shown in Skills Toolkit 1. 

Does the chemical equation tell you anything about the masses of the reactants and products Not directly. But as you learned in Chapter 11, the mass of any substance can be determined by multiplying the number of moles of the substance by the conversion factor that relates mass and number of moles, which is the molar mass. Thus, the mass of the reactants can be calculated in this way. 

Mole ratios You have seen that the coefficients in a chemical equation indicate the relationships among moles of reactants and products. For example, return to the reaction between iron and oxygen described in Table 12-1. The equation indicates that four moles of iron react with three moles of oxygen. It also indicates that four moles of iron react to produce two moles of iron(III) oxide. How many moles of oxygen react to produce two moles of iron(III) oxide You can use the relationships between coefficients to write conversion factors called mole ratios. A mole ratio is a ratio between the numbers of moles of any two substances in a balanced chemical equation. As another example, consider the reaction shown in Figure 12-2. Aluminum reacts with bromine to form aluminum bromide. Aluminum bromide is used as a catalyst to speed up a variety of chemical reactions. 

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