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Keep in mind the Pattern

The molar mass of any type of substance is its atomic mass, molecular mass, or formula mass in grams per mole.

You are watching: Calculate the mass percent of chlorine in ccl3 f (freon-11).



The routine table lists the atomic mass of carbon as 12.011 amu; the average molar mass of carbon—the mass of 6.022 × 1023 carbon atoms—is therefore 12.011 g/mol:


Substance (formula) Atomic, Molecular, or Formula Mass (amu) Molar Mass (g/mol)
carbon (C) 12.011 (atomic mass) 12.011
ethanol (C2H5OH) 46.069 (molecular mass) 46.069
calcium phosphate 310.177 (formula mass) 310.177

The molar mass of naturally arising carbon is different from that of carbon-12 and also is not an integer because carbon occurs as a mixture of carbon-12, carbon-13, and carbon-14. One mole of carbon still has 6.022 × 1023 carbon atoms, however 98.89% of those atoms are carbon-12, 1.11% are carbon-13, and a map (around 1 atom in 1012) are carbon-14. (For more indevelopment, check out Section 1.6 ) Similarly, the molar mass of uranium is 238.03 g/mol, and also the molar mass of iodine is 126.90 g/mol. When we resolve elements such as iodine and also sulhair, which occur as a diatomic molecule (I2) and also a polyatomic molecule (S8), respectively, molar mass commonly refers to the mass of 1 mol of atoms of the element—in this situation I and S, not to the mass of 1 mol of molecules of the facet (I2 and S8).

The molar mass of ethanol is the mass of ethanol (C2H5OH) that includes 6.022 × 1023 ethanol molecules. As you calculated in Example 1, the molecular mass of ethanol is 46.069 amu. Since 1 mol of ethanol consists of 2 mol of carbon atoms (2 × 12.011 g), 6 mol of hydrogen atoms (6 × 1.0079 g), and also 1 mol of oxygen atoms (1 × 15.9994 g), its molar mass is 46.069 g/mol. Similarly, the formula mass of calcium phosphate is 310.177 amu, so its molar mass is 310.177 g/mol. This is the mass of calcium phosphate that contains 6.022 × 1023 formula units.

The mole is the basis of quantitative dearteassociazione.orgistry. It provides dearteassociazione.orgists through a means to convert conveniently in between the mass of a substance and also the number of individual atoms, molecules, or formula devices of that substance. Conversely, it enables dearteassociazione.orgists to calculate the mass of a substance necessary to acquire a wanted variety of atoms, molecules, or formula devices. For example, to transform moles of a substance to mass, we use the relationship


( (moles)(molar ; mass) ightarrow mass ag1.71 )


or, more especially,

( molesleft ( dfracgramsmole est ) = grams )​


To convert from mass to number of pposts, mass is multipled by (1/molar mass) to acquire the variety of moles which is then multiplied by AvogadroShowtime Set It And Forget It Cooking Times, Ronco Showtime Rotisserie Cooking Times

The mass of 1.75 mol of S2Cl2 is calculated as follows:

( moles; S_2Cl_2 left = mass; S_2Cl_2 )

( 1.75; mol; S_2Cl_2left ( dfrac135.036; g; S_2Cl_21;mol;S_2Cl_2 appropriate )=236;g; S_2Cl_2 )

B The formula mass of Ca(ClO)2 is obtained as follows:

1Ca (1 atom )(40.078 amu/atom) = 40.078 amu
2Cl (2 atoms)(35.453 amu/atom) = 70.906 amu
2O (2 atoms)(15.9994 amu/atom) = 31.9988 amu
Ca(ClO)2 formula mass of Ca(ClO)2 = 142.983 amu

The molar mass of Ca(ClO)2 is 142.983 g/mol

( moles; Caleft ( ClO est )_2left < dfracmolar; mass; Caleft ( ClO ight )_21; mol; Caleft ( ClO ideal )_2 ight >=mass; Caleft ( ClO est )_2 )

( 1.75; mol; Caleft ( ClO est )_2left < dfrac142.983; g Caleft ( ClO appropriate )_21; mol; Caleft ( ClO ight )_2 appropriate >=250.; g; Caleft ( ClO ideal )_2 )​

Exercise

Calculate the mass of 0.0122 mol of each compound.

Si3N4 (silicon nitride), supplied as bearings and also rollers (CH3)3N (trimethylamine), a corrosion inhibitor

Answer: