 ### Note the Pattern

The molar mass of any substance is its atom mass, molecule mass, or formula fixed in grams per mole.

You are watching: Molar mass of iodine in grams

The regular table lists the atomic mass the carbon together 12.011 amu; the mean molar fixed of carbon—the massive of 6.022 × 1023 carbon atoms—is thus 12.011 g/mol:

substance (formula) Atomic, Molecular, or Formula massive (amu) Molar fixed (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 various from the of carbon-12 and also is not an integer due to the fact that carbon occurs together a mixture of carbon-12, carbon-13, and carbon-14. One mole that carbon still has actually 6.022 × 1023 carbon atoms, but 98.89% the those atoms are carbon-12, 1.11% space carbon-13, and a map (about 1 atom in 1012) space carbon-14. (For much more information, see ar 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. As soon as we deal with elements such together iodine and sulfur, which occur as a diatomic molecule (I2) and also a polyatomic molecule (S8), respectively, molar massive usually refers to the fixed of 1 mol that atoms that the element—in this situation I and also S, not come the massive of 1 mol the molecules of the aspect (I2 and S8).

The molar massive of ethanol is the massive of ethanol (C2H5OH) that consists of 6.022 × 1023 ethanol molecules. As you calculate in instance 1, the molecular mass that ethanol is 46.069 amu. Because 1 mol that ethanol has 2 mol the carbon atom (2 × 12.011 g), 6 mol of hydrogen atom (6 × 1.0079 g), and 1 mol of oxygen atoms (1 × 15.9994 g), that is molar mass is 46.069 g/mol. Similarly, the formula fixed of calcium phosphate is 310.177 amu, so its molar fixed is 310.177 g/mol. This is the mass of calcium phosphate that consists of 6.022 × 1023 formula units.

The mole is the basis of quantitative charline-picon.comistry. It provides charline-picon.comists with a way to transform easily between the fixed of a substance and the variety of individual atoms, molecules, or formula units of the substance. Conversely, it permits charline-picon.comists to calculation the mass of a substance essential to obtain a desired number of atoms, molecules, or formula units. For example, to convert moles that a substance to mass, we usage the relationship

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

or, an ext specifically,

( molesleft ( dfracgramsmole ight ) = grams )​

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### Example 1.7.2

For 35.00 g of ethylene glycol (HOCH2CH2OH), i beg your pardon is used in inks because that ballpoint pens, calculate the number of

moles. Molecules.

Given: mass and molecular formula

Asked for: number of mole and number of molecules

Strategy:

A use the molecular formula the the compound to calculate its molecular mass in grams every mole.

B convert from massive to moles by separating the mass given by the compound’s molar mass.

C convert from mole to molecule by multiplying the number of moles through Avogadro’s number.

Solution:

A The molecular mass that ethylene glycol can be calculated native its molecular formula making use of the method illustrated in example 1:

 2C (2 atoms)(12.011 amu/atom) = 24.022 amu 6H (6 atoms)(1.0079 amu/atom) = 6.0474 amu 2O (2 atoms)(15.9994 amu/atom) = 31.9988 amu C2H6O molecular fixed of ethanol = 62.068 amu

The molar massive of ethylene glycol is 62.068 g/mol

B The variety of moles the ethylene glycol existing in 35.00 g deserve to be calculation by separating the mass (in grams) by the molar mass (in grams per mole):

( ; 35.00; g; ethylene glycolleft ( frac1; mol; ethylene; glycol; (g))62.068; g; ethylene; glycol ight )=0.5639; mol; ethylene; glycol)

It is constantly a good idea to estimate the price before you carry out the really calculation. In this case, the mass provided (35.00 g) is less than the molar mass, therefore the answer should be less than 1 mol. The calculated price (0.5639 mol) is certainly less than 1 mol, so we have probably no made a major error in the calculations.

C To calculate the number of molecules in the sample, we multiply the variety of moles by Avogadro’s number:

( molecules; of; ethylene; glycol=0.5639; molleft ( dfrac6.022 imes 10^231; mol ight ) )

( = 3.396 imes 10^23; molecules​ )

Exercise

For 75.0 g of CCl3F (Freon-11), calculate the number of

moles. Molecules.

0.546 mol 3.29 × 1023 molecules

### Example 1.7.3

Calculate the massive of 1.75 mol of every compound.

S2Cl2 (common name: sulfur monochloride; organized name: disulfur dichloride) Ca(ClO)2 (calcium hypochlorite)

Given: number of moles and also molecular or empirical formula

Strategy:

A calculate the molecule mass that the link in grams indigenous its molecular formula (if covalent) or empirical formula (if ionic).

B convert from moles to massive by multiplying the moles of the compound provided by the molar mass.

Solution:

We begin by calculating the molecule mass that S2Cl2 and also the formula fixed of Ca(ClO)2.

A The molar massive of S2Cl2 is obtained from its molecular mass together follows:

 2S (2 atoms)(32.065 amu/atom) = 64.130 amu 2Cl (2 atoms)(35.353 amu/atom) = 70.906 amu S2Cl​2 molecular fixed of S2Cl​2 = 135.036 amu

The molar fixed of S2Cl2 is 135.036 g/mol.

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The fixed of 1.75 mol the 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 ight )=236;g; S_2Cl_2 )

B The formula fixed 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 fixed of Ca(ClO)2 = 142.983 amu

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

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

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

Exercise

Calculate the fixed of 0.0122 mol of each compound.

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