Title: Gravimetric Analysis of a Metal Carbonate
Beginning Question: Can you identify a group 1 metal carbonate gravimetrically using a double replacement reaction?
Pre-Lab Questions: See gravimetric analysis packet page 26 for table and questions.
An unknown metal carbonate was analyzed gravimetrically and yielded the information in the table.
Mass of crucible and M2CO3 12.627 g
Mass of crucible 10.655 g
Mass of M2CO3 1.972 g
Mass of filter paper .598 g
Mass of filter paper and CaCO3 2.436 g
Mass of CaCO3 1.838 g
Moles of CaCO3
Molar mass of M2CO3
Identity of M2CO3 Sodium
Percent error
1. Calculate moles of CaCO3 precipitated.
2. Calculate molar mass of M2CO3.
3. Calculate molar mass:
A.) Li2CO3
B.) Na2CO3
C.) K2CO3
4. Identity of M2CO3? The molar mass of the unknown and the molar mass of sodium carbonate are only about 2 g/mol away, the unknown is Sodium.
5. Percent Error?
Procedure: See gravimetric analysis packet page 27.
Data and Observations: The solution was pretty easy to filter because after we stirred in the solid in to the distilled water, we let it set and the solid stayed on the bottom until the watery part was almost finished filtering. Then we took the more solid stuff to put in the filter paper. We didn’t have a very large amount left when we filtered the solution.
Data Table:
Mass of crucible and M2CO3 14.87 g
Mass of crucible 12.86 g
Mass of crucible and M2CO3 (dried) 14.51 g
Mass of M2CO3 1.650 g
Mass of filter paper .71 g
Mass of filter paper and CaCO3 1.850 g
Mass of CaCO3 1.140 g
Moles of CaCO3
Molar mass of M2CO3
Identity of M2CO3
Percent error
Calculations/Post Lab Questions:
1.)
2.)
3.)
4.)
5.) If our filtered calcium carbonate wasn’t completely dry, we would have a larger mass, resulting in a larger percent error because of the molar mass. We could have misread out scale when we were massing anything, like the crucible or filter paper. When...