Compounds one mole

Mole A mole is a measure of amount of substance. One mole is the formula weight of the substance expressed in grams. For example, for limonene, formula C10H16, the formula weight is (C = 12) (10 x 12) + (16 x 1) (H = 1) = 136 so that one mole of limonene is 136 grams of the compound. One mole of any substance contains the same number of units (atoms, molecules or ions). This is termed the Avogadro number, 6.022 x 1023 in scientific notation. 

Notice in Table 1 that the same about 25 joule rule also applies to the molar heat capacities of solid ionic compounds. One mole barium chloride has three times as many ions as atoms in 1 mol of metal. So, you expect the molar heat capacity for BaCl2 to be C = 3 x 25 J/K mol. The value in Table 1,75.1 J/K mol, is similar to this prediction. 

Because no simple NaCl molecules exist at ordinary temperatures, it is inappropriate to refer to the molecular weight of NaCl or any ionic compound. One mole of an ionic compound contains 6.02 X 1Q23 formula units of the substance. Recall that one formula unit of sodium chloride consists of one sodium ion, Na+, and one chloride ion, Cl . One mole, or 58.4 g, of NaCl contains 6.02 X 1023 ]Sy[2+ 5 q2 x 1023 CC ions (Table... 

The alkylated product obtained by the reaction of methyl iodide and bis(/3-mercaptoethylamine)palladium(II) was shown to have the structure (LXVI). In this compound, one mole of the coordinated ligand is replaced... 

Avogadro s number tells us that one mole of a compound contains 6.02 x 10 of the particular type of particles that make up that compound. One mole of a molecular compound contains Avogadro s number of molecules. For example, 1 mole of CO2 contains 6.02 x 10 molecules of CO2. One mole of an ionic compound contains Avogadro s number of formula units, which are the groups of ions represented by the formula of an ionic compound. One mole of NaCl contains 6.02 X 10 formula units of NaCl (Na, CF). Table 7.1 gives examples of the number of particles in some 1-mole quantities. 

Recall that in Chapter 2 a mole was defined as an amount of substance having the same number of elementary entities as there are atoms in exactly 12 g of pure carbon-12. This definition carefully avoids saying that the entities to be counted are always atoms. As a result, we can apply the concept of a mole to any quantity that we can represent by a symbol or formula—atoms, ions, formula units, or molecules. Specifically, a mole of compound is an amount of compound containing Avogadro s number (6.02214 X 10 ) of formula units or molecules. The molar mass is the mass of one mole of compound—one mole of molecules of a molecular compound and one mole of formula units of an ionic compound. 

A more useful quantity for comparison with experiment is the heat of formation, which is defined as the enthalpy change when one mole of a compound is formed from its constituent elements in their standard states. The heat of formation can thus be calculated by subtracting the heats of atomisation of the elements and the atomic ionisation energies from the total energy. Unfortunately, ab initio calculations that do not include electron correlation (which we will discuss in Chapter 3) provide uniformly poor estimates of heats of formation w ith errors in bond dissociation energies of 25-40 kcal/mol, even at the Hartree-Fock limit for diatomic molecules. 

In the normal process ( ), step (J) occurs very rapidly and step (/) is the rate-determining step, whereas in the inhibition process (B), step (3) occurs very slowly, generally over a matter of days, so that it is rate determining. Thus it has been demonstrated with AChE that insecticides, eg, tetraethyl pyrophosphate and mevinphos, engage in first-order reactions with the enzyme the inhibited enzyme is a relatively stable phosphorylated compound containing one mole of phosphoms per mole of enzyme and as a result of the reaction, an equimolar quantity of alcohoHc or acidic product HX is hberated. 

Water. Based on the overall balanced equation for this reaction, a minimum of one mole of water per mole of nitro compound is required for the reduction to take place. In practice, however, 4 to 5 moles of water per mole of nitro compound are used to ensure that enough water is present to convert all of the iron to the intermediate ferrous and ferric hydroxides. In some cases, much larger amounts of water are used to dissolve the amino compound and help separate it from the iron oxide sludge after the reaction is complete. 

Guanidines. Guanidines (10) were one of the first aniline derivatives used as accelerators. They are formed by reaction of two moles of an aromatic amine with one mole of cyanogen chloride. Diphenylguanidine (DPG) has enjoyed a resurgence ia demand as an activator for sulfenamides and a co-accelerator ia tire tread compounds which employ siUca fillers for low rolling resistance. Guanidines alone show too Htde activity to be extensively used as primary accelerators. There were no U.S. producers as of mid-1996. 

The alkoxy titanate compounds formed by reaction of one mole of tetraalkyl titanate with one mole of a dialkanolamine are excellent esterification catalysts for the manufacture of phthalate-based plasticizers (112). If a 1 1 molar mixture of alkanolamine and water is used ia place of the alkanolamine, oligomeric titanate complexes are formed, which have high catalyst activity and can be used as thixotropic additives to paints and other aqueous coating formulations (113). 

Peracid Precursor Systems. Compounds that can form peracids by perhydrolysis are almost exclusively amide, imides, esters, or anhydrides (85). Two compounds were commercially used for laundry bleaching as of 1990. Tetraacetylethylenediarnine (TAED) [10543-57-4] is utilized in over 50% of Western European detergents (5). The perhydrolysis reaction of this compound is shown in equation 19. T A ED generates two moles of peracid and one mole of diacetylethylenediamine per mole of imide (93). 

Treatment of pyrrole, 1-methyl-, 1-benzyl- and 1-phenyl-pyrrole with one mole of A -bromosuccinimide in THF results in the regiospecific formation of 2-bromopyrroles. Chlorination with IV-chlorosuccinimide is less selective (8UOC2221). Bromination of pyrrole with bromine in acetic acid gives 2,3,4,5-tetrabromopyrrole and iodination with iodine in aqueous potassium iodide yields the corresponding tetraiodo compound. 

The reaction of ozone with an aromatic compound is considerably slower than the reaction with an alkene. Complete ozonolysis of one mole of benzene with workup under non-oxidative conditions will yield three moles of glyoxal. The selective ozonolysis of particular bonds in appropriate aromatic compounds is used in organic synthesis, for example in the synthesis of a substituted biphenyl 8 from phenanthrene 7 ... 

The standard heat of formation ( AH ) of a chemical compound is the standard heat of reaction corresponding to the chemical combination of its constituent elements to form one mole of the compound, each existing in its standard state at 1 atm and 25°C. It has units of cal/g-mole. 

Knowing the formula of a compound, Fe203> you can readily calculate the mass percents of its constituent elements. It is convenient to start with one mole of compound (Example 3.4a). The formula of a compound can also be used in a straightforward way to find the mass of an element in a known mass of the compound (Example 3.4b). 

The standard molar enthalpy of formation of a compound, AH , is equal to the enthalpy change when one mole of the compound is formed at a constant pressure of 1 atm and a fixed temperature, ordinarily 25°C, from the elements in their stable states at that pressure and temperature. From the equations... 

Naphthalene, Ci0Hs, is the compound present in moth balls. When one mole of naphthalene is burned, 5.15 X 103 kj ofheat is evolved. A sample of naphthalene burned in a bomb calorimeter (heat capacity = 9832 J/°C) increases the temperature in die calorimeter from 25.1°C to 28.4°C. How many milligrams of naphthalene were burned ... 

Write thermochemical equations for the decomposition of one mole of the following compounds into the elements in their stable states at 25°C and 1 atm. 

Write the formulas for the following compounds and give the weight of one mole of each carbon disulfide, sulfur hexafluoride, nitrogen trichloride, osmium tetroxide. 

One mole of an organic compound is found to react with mole of oxygen to produce an acid. To what class of compounds does this starting material belong ... 

One mole of any chemical compound is one mole of its chemical formula unit. Here are some examples ... 

Before we can calculate a molar mass, we need a chemical formula. Then we can calculate the masses of each of the elements in one mole of the compound. 

To determine a chemical formula, we would like to count the atoms of each element in one molecule of the compound. Atoms are too small to count, but we might hope to measure the number of moles of each element present in one mole of the compound. Unfortunately, there is no direct experimental method for measuring moles. Instead, laboratory experiments give the masses of the various elements contained in some total mass of the compound. 

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