We have already investigated the relationship between mass, mole and the number of particles. But, is there any relationship between volume and mass, or mole and number of particles? Lets investigate.

Purpose: Determine if there is a mathematical relationship between the mole and molar volume.

Construct a scatter plot of density versus molar mass for the elements listed below.

TI Directions

Density/Molar Mass Data

Sketch a simple diagram of the graph into your lab report.

Next, examine the following data for gases and determine if there is a mathematical relationship between the density of a gas and it's molar mass. Do this by constructing a scatter plot of molar mass vs. density.

TI Directions

Substance/Density/Molar Mass Data

Calculate the line of best fits for the graph of Molar Mass (g/mol) vs. Density (g/L) . Record the regression equation in your lab note book and add the regression line to your graph.

TI Directions

Sketch a simple diagram of the graph into your lab report and record the regression equation.

Questions:

  1. Is there a relationship between molar mass and density?
  2. Is it correct to assume a (0,0) origin for the graph ? Explain.
  3. What does the slope of the line represent?
  4. What is the numerical value (with label) for the slope of the line?
  5. If the molar mass is in grams per mole, then what might be an appropriate term for grams per liter?
  6. What are STP conditions?
  7. The molar volume is a constant value for gases kept at STP. Why would the temperature and pressure be important considerations in the volume of a gas?
  8. Scientists can count the particles of a solid or liquid by _____________ the sample. Scientists can count the particles of a gas by __________________ the volume of a gas at _____________________.