Gravimetric Analysis Of Calcium Carbonate
The purpose of this lab is to find the mass of an unknown metal by conducting a double-displacement precipitation reaction, which is our gravimetric analysis. Once we find the precipitate mass, we can then find the molar mass by using the molar ratio given in the reaction equation.
First, we set up the ring stand with a Bunsen burner, put a crucible on top of the pipe stem triangle and heated the crucible for a minute, then let it cool down. We then massed the crucible and added two grams of the unknown carbonate to the crucible, then recorded its combined mass. We then repeatedly heated, cooled, and massed the crucible until the mass of the crucible and the unknown carbonate no …show more content…
Then, it was simply a matter of solving for the unknown metal and once we found how much the metal weighed, a quick glance at our periodic table identified the metal as sodium. The low percent error of 0.377% is indicative of the accuracy of this experiment.
Possible sources of error include the unknown carbonate absorbing water during the heating and cooling process. There also may have been human error when the solid contents when transferred to the filter paper because perhaps not all of the contents were completely transferred. In addition, the measurements of how much liquid was poured into the beaker may be off.
Post Lab Questions
1. The moles of CaCO3 is 0.01828 because the mass of CaCO3 is 1.830 grams, therefore in order to get the moles of CaCO3, we must divide 1.830 by the molar mass of CaCO3, which is 100.1. This yields 0.01828 moles.
2. Dividing the mass of the unknown carbonate by the moles of CaCO3 will yield the molar mass of M2CO3. Therefore, 1.931 /0.01828 is 105.6 grams per