Small Scale Lab

Measuring Mass As A Means Of Counting

Alexandra Montalvo

Purpose:

To determine the mass of several chemical compound samples and use the data to count atoms.

Materials: 

Pencil

Paper 

Plastic spoon

Balance

Ruler

Procedure:

Measure the mass of one level teaspoon of sodium chloride (NaCl), water (H2O), and calcium carbonate (CaCO3). Make a table similar to Figure A to record your measured and calculated data.

 Data Table:

    H20:

Mass (g) -    6.0 g

Molar Mass (g/mol) -      18.0 g

Moles of Each Compound -  .33 moles

Moles of Each Element  -      3.3 moles

Atoms of Each Element  -   2 Hydrogen atoms

                                                  1 Oxygen atom

      NaCl:  

Mass (g)  -  10.5 g

Molar Mass (g/mol)  -  58.5 g

Moles of Each Compound  -  .179 moles

Moles of Each Element  -  58.4 moles 

Atoms of Each Element  -  1 Sodium atom

                                                 1 Chlorine atom

      CaCO3:   

Mass (g)  -   7.5 g

Molar Mass (g/mol)  -  100.1 g

Moles of Each Compound  -  .75 moles

Moles of Each Element  -  101 moles

Atoms of Each Element  - 1 Calcium atom

                                                1 Carbon atom

                                                3 Oxygen atom

Analysis Questions:

1. Which of the three teaspoon sized samples contains the greatest number of moles?

- I would say NaCl has the greatest number of moles.

2. Which of three compounds contains the most atoms?

- The compound that contains the most atoms is CaCO3.