Quantitative Determination
of an
Empirical Formula
INSTRUCTIONS:
Read the introduction to Lab 7 pages 45 and 46.
PROCEDURE:
Follow the general procedure found in your lab text with the following changes.
1. Prepare a data table.
2. A Bunsen burner will be used.
3. Clean, dry and mass to the nearest 0.01-g an evaporating dish and a watch glass. Record the
mass.
4. Set your scale to read an additional 2-g. Ask your instructor to provide you with the
granulated tin. Record the mass.
5. Obtain your nitric acid. If your mass of tin is less than or greater than 2.00-g determine the
correct volume of acid needed. More acid is fine, too little acid will give incorrect results.
6. Slowly add your volume of 8-M nitric acid. Replace the watch glass and allow the reaction to
take place. If the above concentration of acid is not available use the amount your instructor
recommends.
7. Follow procedure 6, heat directly over a burner flame, and do not use the water bath shown in
Figure 7-1.
8. Follow procedure 7 in book.
9. Follow procedure 8 in book.
10. Follow procedure 9 in book. The mass after the second heating must be within 0.02-g of the
mass from the first heating. If it does not agree you must heat for several more minutes until
your last two masses agree within 0.02-g.
11. Follow book.
Lab Report:
In your conclusion section answer questions 1 and 2.
On a separate piece of paper complete questions 2 through 5 in the further investigations.