Conversion factors chemical formulas

Decide which conversion factors, mathematical formulas, or chemical principles you will need to solve the problem. Your plan might suggest a single calculation or a series of them involving different conversion factor s. Once you understand how you need to proceed, you may wish to sketch out the route you will take, using arrows to point the way from one stage of the solution to the next. Sometimes you will need data that are not actually part of the problem statement For instance, you ll often use data from the periodic table. 

Exact numbers, such as the stoichiometric coefficients in a chemical formula or reaction, and unit conversion factors, have an infinite number of significant figures. A mole of CaCb, for example, contains exactly two moles of chloride and one mole of calcium. In the equality... 

C03-0042. Diagram the process for converting from the mass of a compound of a known chemical formula to the number of atoms of one of its constituent elements. Include all necessary equations and conversion factors. 

For work in the laboratory, it s necessary to weigh reactants rather than just know numbers of moles. Thus, it s necessary to convert between numbers of moles and numbers of grams by using molar mass as the conversion factor. The molar mass of any substance is the amount in grams numerically equal to the substance s molecular or formula mass. Carrying out chemical calculations using these relationships is called stoichiometry. 

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 chemical formula for a compound gives the ratio of atoms of each element in the compound to atoms of every other element in the compound. It also gives the ratio of dozens of atoms of each element in the compound to dozens of atoms of every other element in the compound. Moreover, it gives the ratio of moles of atoms of each element in the compound to moles of atoms of every other element in the compound. For example, a given quantity of H2O has 2 mol of H atoms for every mole of O atoms, and a given quantity of CH4 has 1 mol of C atoms for every 4 mol of H atoms. The mole ratio from the formula can be used as a factor to convert from moles of any element in the formula to moles of any other element or to moles of the formula unit as a whole. In Figure 7.2, these additional conversions have been added to those already presented in Figure 7.1. 

The number of moles of an element in a mole of componnd can also be used to calculate the number of moles of the compound involved in a reaction. The ratio of the number of moles of an element within a compound to the number of moles of the compound is determined by the compound s chemical formula (Section 7.3). Thns, the snbscripts of the formula may be used to form conversion factors. 

The graphs are arranged by carbon number and chemical formula to provide ease of use. English units are used for the property values. For those involved in SI and metric usage, each graph displays a conversion factor to provide the SI and metric units. 

Conversion factors such as the one just used for fluorine can he written for any element in a compound. The number of moles of the element that goes in the numerator of the conversion factor is the subscript for that element in the chemical formula. 

You are given the number of moles of AI2O3 and must determine the number of moles of AP+ ions. Use a conversion factor based on the chemical formula that relates moles of Al + ions to moles of AI2O3. Every mole of AI2O3 contains two moles of Al + ions. Thus, the answer should be two times the number of moles of AI2O3. 

The mass of your backpack is the sum of the mass of the pack plus the masses of the books, notebooks, pencils, lunch, and miscellaneous items you put into it. You could find its mass by determining the mass of each item separately and adding them together. Similarly, the mass of a mole of a compound equals the sum of the masses of every particle that makes up the compound. You know how to use the molar mass of an element as a conversion factor in calculations. You also know that a chemical formula indicates the number of moles of each element in a compound. With this information, you can now determine the molar mass of a compound. 

Example Problem 11-8 illustrated how to find the number of moles of a compound contained in a given mass. Now, you will learn how to calculate the number of representative particles—molecules or formula units—contained in a given mass and, in addition, the number of atoms or ions. Recall that no direct conversion is possible between mass and number of particles. You must first convert the given mass to moles by multiplying by the inverse of the molar mass. Then, you can convert moles to the number of representative particles by multiplying by Avogadro s number. To determine numbers of atoms or ions in a compound, you will need conversion factors that are ratios of the number of atoms or ions in the compound to one mole of compound. These are based on the chemical formula. Example Problem 11-9 provides practice in solving this type of problem. 

You are given 35.6 g AICI3 and must calculate the number of Al + ions, the number of Cl ions, and the mass in grams of one formula unit of AICI3. Molar mass, Avogadro s number, and ratios from the chemical formula are the necessary conversion factors. The ratio of AP+ ions to CE ions in the chemical formula Is 1 3. Therefore, the calculated numbers of ions should be in that ratio. The mass of one formula unit in grams should be an extremely small number. 

To calculate the number of AP+ and Cl ions, use the ratios from the chemical formula as conversion factors. 

This section is designed to fill the gap between the familiar formulas presented above and the assumptions and definitions of terms and physical constants needed to apply them. Values for all physical constants and needed conversion factors are provided, and dimensional analyses are included to show how the final results and their units are obtained. This close focus on the details and units of the equations themselves is followed by worked examples from the chemical literature. The goal is to provide nearly everything the interested reader may need to evaluate his or her own data, with reasonable confidence that he or she is doing so correctly. 

To complete these steps, we need one additional kind of conversion factor that converts between moles of an element and moles of a compound containing that element. We obtain this conversion factor from the compound s chemical formula. For example, the formula for hexane, C6H14, tells us that each hexane molecule contains six... 

The ratio of moles of P4O10 to moles of P (which came from the subscripts in the chemical formula, P4O10) provided the key conversion factor that allowed us to convert from units of phosphorus to units of tetraphosphorus decoxide. 

A mole of substance is the amount that contains Avogadro s number (6.022x10 ) of chemical entities (atoms, molecules, or formula units). The mass (in grams) of a mole has the same numerical value as the mass (in amu) of the entity. Thus, the mole allows us to count entitles by weighing them. Using the molar mass (jM., g/mol) of an element (or compound) and Avogadro s number as conversion factors, we can convert among amount (mol), mass (g), and number of entities. The mass fraction of element X in a compound is used to find the mass of X in any amount of the compound. 

Figure 3.8 Summary of the mass-mole-number relationships in a chemical reaction. The amount of one substance in a reaotion is related to that of any other. Quantities are expressed in terms of grams, moles, or number of entities (atoms, molecules, or formula units). Start at any box in the diagram (known) and move to any other box (unknown) by using the information on the arrows as conversion factors. As an example, if you know the mass (in g) of A and want to know the number of molecules of B, the path involves three calculation steps ...

Avogadro s number, molar mass, and the chemical formula of a compound are three useful conversion factors. What unit conversions can be accomplished using these conversion factors ... 

Conversions between mass, moles, and the number of particles are summarized in Figure 10.11. Note that molar mass and the inverse of molar mass are conversion factors between mass and number of moles. Avogadros number and its inverse are the conversion factors between moles and the number of representative particles. To convert between moles and the number of moles of atoms or ions contained in the compound, use the ratio of moles of atoms or ions to 1 mole of compound or its inverse, which are shown on the upward and downward arrows in Figure 10.11. These ratios are derived from the subscripts in the chemical formula. 

The necessary basic knowledge is provided in Chapter 2 The Chemical Production Plant and its Components. It deals vhth important subdisciplines of technical chemistry such as catalysis, chemical reaction engineering, separation processes, hydrodynamics, materials and energy logistics, measurement and control technology, plant safety, and materials selection. Thus, it acts as a concise textbook vhthin the book that saves the reader from consulting other works when such information is required. A comprehensive appendix (mathematical formulas, conversion factors, thermodynamic data, material data, regulations, etc.) is also provided. 

Contents Background and Technical Aspects of the Chemical Industry. - Air Quality and Emission Control. - Water Quality Emission Control. - Natural and Derived Sodium and Potassium Salts. - Industrial Bases by Chemical Routes. - Electrolytic Sodium Hydrocide and Chlorine and Related Commodities. -Sulfur and Sulfuric Add. - Phosphorus and Phosphoric Acid. - Ammonia, Nitric Add and their Derivatives. - Aluminium and Compounds. - Ore Enrichment and Smelting of Copper. - Production of Iron Steel. - Production of Pulp and Paper. - Fermentation Processes. - Petroleum Production and Transport. - Petroleum Refining. - Formulae and Conversion Factors. - Subject Index. 

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