Gram-molecular mass

This kind of quantity, called the gram molecular mass, is exceptionally convenient for chemists, who are much more inclined to measure the mass of a substance than to count all the individual particles that make up a sample. 

Chemists may distinguish between the molar masses of pure elements, molecular compounds, and ionic compounds by referring to them as the gram atomic mass, gram molecular mass, and gram formula mass, respectively. Don t be fooled The basic concept behind each term is the same molar mass. 

Divide the gram molecular mass by the empirical formula mass. 

Q. What is the molecular formula of a compound that has a gram molecular mass of 34 g/mol and the empirical formula HO ... 

A compound has a percent composition of 49.5% carbon, 5.2% hydrogen, 16.5% oxygen, and 28.8% nitrogen. The compound s gram molecular mass is 194.2 g/mol. What are the empirical and molecular formulas ... 

In a 194.20 g sample, 78.20 g is potassium, 52.00 g is chromium, and 64.00 g is oxygen. Divide each of these masses by the gram molecular mass, and then multiply by 100 to get the percent composition ... 

Dividing the gram molecular mass you were given (194.2 g/mol) by this empirical formula mass yields the quotient, 2. Multiplying each of the subscripts in the empirical formula by 2 produces the molecular formula, CgHjgN 02. The common name for this culturally important compound is caffeine. 

In chemistry we have traditionally expressed the amount of a substance i in a system of substances in terms of the number of moles nt - mi/Mi instead of its mass mt, where M denotes the gram molecular mass of the substance i. The composition of the system of substances is expressed accordingly by the molar fraction xt as defined in Eq. 1.1 ... 

Mole is abbreviated mol. Do not use m or M for mole these symbols are used for other quantities related to moles, and so you will be confused if you use either of them. Note A mole is referred to by some authors as a gram molecular mass because 1 mol of molecules has a mass in grams equal to its molecular mass. In this terminology, a gram atomic mass is 1 mol of atoms, and a gram formula mass is 1 mol of formula units. 

Here M, represents the gram molecular mass of species i, and g, the gravitational constant. The expression shows explicitly how the total energy in the volume element changes through the influx or outflow of gaseous species through any particular volume element. 

Atoms and molecules are incredibly small. Just as the dozen is used as a convenient number of items in everyday life, chemists use the mole to describe quantities of atoms or molecules. One mole is 6.02 x 10 items, a number called Avogadro s number. Using moles simplifies calculations. The number of formula units can be converted to moles of the same substance, and vice versa, using Avogadro s number. Some authors refer to a mole as a gram molecular mass because one mole of molecules has a mass in grams equal to its molecular mass. Mole is abbreviated mol. 

Occasionally, one encounters gram-atomic mass (GAM), gram-formula mass (GFM), and gram-molecular mass (GMM). These terms are functionally the same as molar mass. For example, the GAM of an element is the mass in grams of a sample containing atoms and is equal to the element s atomic... 

For most of the questions we will be called upon to answer, working with the actual numbers of molecules is awkward because there are so many of them in even the most minute portions of matter. This awkwardness can be removed, however, by using 6.023 x 10 molecules Avogadro s number, the number of C atoms in exactly 12g of C), the chemist s "dozen," as a basic unit. The amount of matter containing an Avogadro number of molecules of any substance is called a mole. This amount will have a mass in grams equal to its gram molecular mass (GMW). To calculate the... 

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