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Counting Molecules (1)

In this video we'll show you how to scoop solids and use the balance:

  1. To start this activity, click this link for Counting Molecules (1). The lab will load in a new tab. Click back to this tab to read further instructions and complete the questions below. You can follow along with the instructions below in the Procedures tab in the lab.
  2. Expand the Samples menu in the Stockroom tray. Then expand the Salts menu and select NaCl - 100%. You'll see a bottle appear on the stockroom counter with the salt sample.
  3. Drag the bottle to the spotlight near the balance, and click on the Balance area to zoom in. Drag a piece of weighing paper to the balance pan and then Tare the balance so the balance reads 0.0000 g. Click on the bottle lid (Remove Lid) to remove the lid.
  4. Click on the image of the largest sample in a scoop on the front of the bottle to load the scoop with approximately 1 g. Drag the scoop to the weighing paper on the balance until it snaps in place and then let go. This will put approximately 1 g of sample on the balance. 

Record the mass of the sample. 

g NaCl


  1. Calculate the moles of NaCl contained in the sample.

mol NaCl


6.         Calculate the moles of each element in NaCl. 

Moles Na =


Moles Cl =


7.         Calculate the number of atoms for each element in NaCl.     

Atoms Na =  


Atoms Cl =