CHEM 1105: GRAVIMETRIC ANALYSIS Name: _______________ Date:_________________ Section__________________ Objective: Procedure: As in Kwantlen Chemistry 1105 lab manual, pages __________. Observations Data Table 1. Mass of Sample Unknown Number Mass of vial and all M2CO3 (g) Mass of vial and remaining M2CO3 (g) Mass of empty vial (g) Table 2. Mass of Precipitate Measurment Run 1 Run 2 Mass of M2CO3 (g) Mass of empty crucible (g) Mass of precipitate and crucible (g) Mass of precipitate (g) KPU, Chem 1105 July 2013 1 Calculations: Show all your calculations below. You only need to show calculations for one run. 1. The molar mass of calcium carbonate: 2. The number of moles of calcium carbonate obtained: 3. Write a balanced chemical equation, and use it to determine the number of moles of unknown metal carbonate. You can use a generic formula for the metal carbonate ie MxCO3 4. The molar mass (grams/mole) of the unknown carbonate is: 5. The average molar mass of the unknown is (If the two molar masses do not agree within 10 grams, do not average them; simply report the two values):2 KPU, Chem 1105 July 2013 2 6. As you are told the unknown metal is an alkali metal, the formula of the unknown metal carbonate must be M2CO3. Therefore, calculate the atomic mass of the metal using the atomic masses of oxygen and carbon: 7. Suggest the identity of the unknown metal M: 8. Now calculate the difference between the expected molar mass of your metal carbonate and the molar mass of the metal carbonate you obtained experimentally: Results: unknown #: ____ Calculated molar mass of metal carbonate KPU, Chem 1105 Run 1 Run 2 Average (or Best Value if One Run Had Known Error) July 2013 3 Conclusion: Questions Answer any assigned questions here. KPU, Chem 1105 July 2013 4