The Size of Molecules Worksheet

Name:_______________________

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You may use the back of this sheet for calculations.

Warm-up Data and Calculations

Length of Foil = ______________

Width of Foil = ______________

Mass of Foil = ______________

1. Calculate the volume of the foil. Show your work.

    

    

    

    

2. Calculate the thickness of the foil. Show your work.

 

 

 

  Monolayer Thickness Data and Calculations

Number of drops to Equal 1.0 ml = ______________

Number of drops of Oleic Acid Solution Used = ______________

Diameter of clear area:

Trial 1 = ______________

Trial 2 = ______________

Trial 3 = ______________

Average = ______________

 

 

1. Calculate the area of the clear surface. This is the area covered by the oleic acid.

    

    

    

2. Calculate the volume of pure oleic acid using these steps:
   1. Convert drops of solution to ml by dividing the number of drops you used by the number of drops needed to equal 1.0 ml.

       

       

       

   2. Multiply that answer by 0.05. The answer is the volume of pure oleic acid expressed in ml (which, remember, are equal to cm³)

    

    

    

3. Use the following equation to calculate the thickness of the layer of oleic acid on the water:
   V = (p)(r ²)(h)

   In this equation V is the volume of pure oleic acid, r = the radius of the clear acid region on the water (diameter/2), and h is the thickness you want to find. If we assume that the layer is a single molecule thick, the answer to this calculation is the size of a single molecule of oleic acid.

    

    

    

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