The Challenge for this weeks worksheet is to use the numbers obtained by a student to complete the “Identification of unknown Metal Carbonate” pages in the lab manual (pg 65-66) then submit a pdf copy to the Gradescope page. Deadline Friday Oct 9 at 5 pm. A video of the experimental basics is athttps://www.youtube.com/watch?v=V6jP1Jt59Xc To prepare for the experiment you need to read the lab manual pg 59-63, paying specific attention to how the mass percent of CO2 is determined for a compound. You will need to calculate Mass percent of CO2 for each of the Carbonates listed in table 9-3. Remember that if you have a “hydrate” as shown on page 60, you must use the entire Molar mass including the number of water molecules to find the correct theoretical percent CO2. The goal is to use the numbers generated by a student to find your unknown. The scene: A student weighed a beaker and test tube, mass was determined as 129.02 g. Some Lithium Carbonate was added and now the mass was 130.22 g. Acid was added to the test tube and the total mass before reaction was 139.73 g. The acid was dumped into the beaker (see video for observations) and now the entire assembly weighed 139.01 g.It is up to you to use these numbers to make sure you know how to do the calculations and get the correct mass percent for Lithium Carbonate. Next the student took an unknown carbonate and performed the same steps, repeating for accuracy. Items weighed Trial 1 Trial 2 Beaker + test tube 136.14 g 134.75 g Beaker + test tube +carbonate 137.25g 136.04 g Beaker + test tube +carbonate + acid 146.87 g 148.22 g Mass of assembly after reaction 146.69 g 147.99 g The calculations and questions to answer: Use this information to fill in the tables on pg 65, in table 9-1 you should be able to obtain the correct mass percent for Lithium Carbonate. This allows you to make sure you understand the process.Fill in the data table 9-2 for your unknown carbonate. Find the Mass % of CO2 in the unknown carbonate, compare to table 9-3 ( that you filled out in the preparation for this lab) and name which unknown you have.Find the % error in your results (question 1) remembering that the error is an absolute value.Watch the video again to think about sources of error. List 3, and decide which could have the greatest impact on your results.Apply what you learned when calculating % CO2 in a carbonate, and calculate % Cl in Group II metal chlorides. It is the same procedure, but now you are considering chlorine instead of CO2. If you do not remember what Group II is, use your textbook to refresh your memory. Remember to show calculations for all sections.
Identification of Unknown Metal Carbonate Questions