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.

• If the molar mass (g/mole) is divided by the density (g/mL), what units remain?
• What would be an appropriate name for measurements having units in moles per mL?

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

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

• Does the data between molar mass and the density of the various metals seem to fit an easily recognized mathematical function?

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.

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.

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

• Y=

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 _____________________.