Measuring Mass Lab

Measuring Mass: Calculating Moles

You can measure how much of something you have by counting individual objects. For example, you can count the number of cookies in a bag or the number of pages in your notebook. There is a name for a number of atoms, ions, or molecules. One mole of a substance is equal to 6.02 x 1023 atoms, ions, or molecules of that substance. You can determine the number of moles in a substance by obtaining the mass of the substance.

Objectives  To measure the masses of common compounds and objects  To calculate the moles and atoms from the experimental masses

Materials  salt (NaCl)

 sugar (C12H22O11)

 chalk (CaCO3)

 sand (SiO2)

 water (H2O)  balance  spoon

Procedure 1. Mass one level teaspoon of salt (NaCl). Record the mass in the Data Table. Repeat for each of the compounds listed in the materials.

Data Table

Moles of Atoms of Mass Molar Moles in 1 Formula Name each each in mg Mass teaspoon element element 0.11 Na NaCl Salt 6300 58g/mol 0.11 0.11 Cl

C12H22O11 Sugar

CaCO3 Chalk

SiO2 Sand

H2O Water

1. Calculate the number of moles of one level teaspoon of salt (NaCl). Repeat for all the other compounds. Fill in the appropriate boxes on the Data Table.

2. Calculate the number of moles of each element in one level teaspoon of salt (NaCl). Repeat for all the other compounds. Fill in the appropriate boxes on the Data Table.

3. Calculate the atoms of each element for one level teaspoon of salt (NaCl). Repeat for all the other compounds. Fill in the appropriate boxes on the Data Table.

4. You measured equal volumes for each of the different compounds. Which of the compounds has the greatest number of moles in one teaspoon?

5. Which of the compounds has the greatest total number of atoms?

6. Why can you use the technique of measuring volume as a means of counting?