Make your own free website on

        Click to Go Home

Molar Mass Lab Analysis Questions

1.     Determine the mass of the small objects that were in your container.
2.     Determine the average mass of the 5 small objects that you measured.
3.     Using the average mass and the mass of all of the objects combined, determine the number
        of objects that you had in your container.
4.     Compare this number to the number that you actually counted.  Were you close?
5.     Write out the relationship between grams, moles, and formula units/molecules for each of
        the following:


Using the relationships from part 5 and the measured masses, determine each of the following:

6.       How many formula units of NaCl were in one scoop of NaCl?
7.       How many moles of NaCl were in one scoop of NaCl?
8.       How many molecules of H2O were in your small beaker?
9.       How many moles of H2O were in the beaker?
10.     How many molecules of C12H22O11 were in one scoop?
11.     How many moles of C12H22O11 were in one scoop?
12.     How many ATOMS of H are there in 1 mole of C12H22O11?
13.     How many moles of H are in 3.0 g of H2O?


1. Explain how you were able to determine the number of small objects in the cup without
actually counting them individually.

2. What is the connection between what you did in the first part of the lab (i.e. with the small
objects) and the remainder of the lab.

3. What is the significance

Selected Answers

5.    58 g NaCl = 1 Mol NaCl = 6.02 x 1023 NaCl
        18 g H2O = 1 Mol H2O = 6.02 x 1023 NaCl
        342 g C12H22O11 = 1 Mol C12H22O11 = 6.02 x 1023 C12H22O11

12.    22 x 6.02 x 1023 atoms H
13.    3 / 18 x 2 = 3.7 mol