Pre-Laboratory Assignment: Determining the Molar Mass of a Metal
- Prepare a data table in your bound notebook using the sample table as a guide. When you record the actual data, be sure to indicate the units of measurement.
- Do metals react with acids? If so, what products are most typically formed?
- Do all metals react with acids? How can you tell whether a reaction will occur?
- Give 3 examples of metals that do not react with acids
- What about zinc, aluminum, and magnesium—do they react?
- Write the balanced un-ionized equation and the net ionic equation for the reaction of each of the following metals with hydrochloric acid: zinc, aluminum, and magnesium.
- The release of a gaseous product is a powerful driving force for a reaction. An additional driving force is to use an excess of one reactant to assure the reaction goes to completion. In this experiment which reactant should be used in excess? Justify your answer using complete sentences. (No calculations are necessary.)
Experiment 4: Determining the Molar Mass of a Metal 57
- Confirm your expectation in question 3 quantitatively by working a limiting reactant problem. Use the volume and molarity of HCl(aq) and the maximum mass suggested for zinc in Part II. Show all of your work.
- The experimental procedure has you carefully measure the volume of hydrogen gas produced from the reaction of a given amount of metal. How does the measurement of the volume of a gas help you determine the molar mass of a metal? Answer this question by detailing the “road map” of calculations that will be necessary to reach the goal of this experiment.
- What properties, conditions, or values must you be sure to measure (in addition to the volume of the gas) if you are going to have the information you need for these calculations?
Experiment 4: Determining the Molar Mass of a Metal 58