Molar mass calculation worksheet

Unit 4
Molar Mass Worksheet
Molar mass is the mass of one mole of substance. It is number of the atomic mass from the periodic table,
but written as grams. Read the Unit 4 Notes on slides 13-18 and Section 10.2 in your textbook, then practice
calculating the molar mass for these elements and compounds. You will need a periodic table.
Show your calculations to get full credit for this assignment.
DO NOT google the answers - you will not learn anything that way!
Example: Carbon has atomic mass of 12.011, so its molar mass is 12.011 g.
For compounds: add up the atomic masses of all the elements
CH4, has one carbon and four hydrogens, so. . . 12.011 g + 1g +1g +1g +1g = 16.011 g
Calculate the molar masses of the following elements and compounds:
1) Chlorine gas

Cl2 has two chlorines, so its molar mass is 35.453 g + 35.453 g = 70.906 g



2) CH3COOH

CH3COOH has two carbons, four hydrogens and two oxygens, so its molar mass is 12.011 g + 12.011 g + 1.008 g

+ 1.008 g + 1.008 g + 1.008 g + 15.999 g + 15.999 g = 60.052 g



3) gold

Gold has atomic mass of 196.967, so its molar mass is 196.967 g



4) FeCl3

FeCl3 has one iron and three chlorines, so its molar mass is 55.847 g + 35.453 g + 35.453 g + 35.453 g = 162.206

g



5) Boron trifluoride

BF3 has one boron and three fluorines, so its molar mass is 10.81 g + 18.998 g + 18.998 g + 18.998 g = 67.804 g



6) CCl2F2