Please be specific!
Briefly explain whether each if the following procedural errors would result in a high, low, or an unchanged calculated mass of Ca2+ in the analyzed tablet.
a)a student had difficulty decanting the supernatant solution from the test tubes in step 9, causing him to transfer some of the solid along with the solution.
b)when rinsing the binder material from the test tubes, student observed small pieces of undissolved tablet in the solid at the bottom of the tubes.
c)a student found that the litmus paper did not turn blue when tested with a drop of the solution, then failed to add additional Na_2_CO_3_ solution and test the solution again beforeproceeding to the next step.
d)a student discarded the torn-off filter paper corner, instead of placing it in the cone
e)after labeling the filter paper, a student left wet fingerprints on the paper when transferring it to the balance to determine its mass.
f)a student failed to determine the mass of the filter paper prior to filtering the CaCO_3_. Realizing the importance of this mass, he selected a new piece of filter paper and used its mas in his calculations.
2)Briefly expalin why you can use this experiment's procedure to determine the number of milligrams of Ca2+ ion in a food sample in which the Ca2+ ion is present in a form ofther than CaCO_3_
I don't have any idea what procedure you used. If you wish to type in the ENTIRE procedure perhaps someone here can help but you can do this yourelf the following way.
Write an equation for each step. Substitute (mentally) high or low for the part of the equation that is changing, determine the effect at that stage, then go to the next step. Here is an example.
Doing an experiment for % Ca in lime (Ca(OH)2 in a sample by titrating with 0.1M HCl
2HCl + Ca(OH)2 ==> CaCl2 + 2H2O
1. mols HCl = mL x M
2. mols Ca(OH)2 = mols HCl/2
3. g Ca(OH)2 = mols Ca(OH)2 x molar mass Ca(OH)2.
4. %Ca(OH)2 = (mass Ca(OH)2/mass sample)*100 = ?
question: How will percent Ca(OH)2 be affected if we over titrate with HCl; i.e., add too much HCl.
Too much HCl in step 1 (mL too high) means mols too high. Go to step 2.
Too many mols HCl in step 1 means too many mols Ca(OH)2 in step 2. Go to 3.
Too many mols Ca(OH)2 means grams Ca(OH)2 will be too high and that substituted into 4 for mass Ca(OH)2 gives high results for percent Ca(OH)2.
See your post under the screen name anne. It takes longer to answer questions with different screen names.
a) This procedural error would result in a high calculated mass of Ca2+ in the analyzed tablet. By transferring some of the solid along with the solution, the student would be including additional calcium ions in the analysis, leading to an overestimate of the amount of Ca2+ in the tablet.
b) This procedural error would result in an unchanged calculated mass of Ca2+ in the analyzed tablet. The small pieces of undissolved tablet would not affect the measured mass of Ca2+ in the solution, as they would be filtered out during the process.
c) This procedural error would result in a low calculated mass of Ca2+ in the analyzed tablet. By not adding additional Na2CO3 solution and retesting the solution, the student would fail to fully react and precipitate all of the Ca2+ ions present. As a result, the measured mass of Ca2+ would be lower than the actual amount in the tablet.
d) This procedural error would result in an unchanged calculated mass of Ca2+ in the analyzed tablet. Discarding the torn-off filter paper corner would not affect the measured mass of Ca2+ in the tablet or the accuracy of the analysis.
e) This procedural error would result in a high calculated mass of Ca2+ in the analyzed tablet. The wet fingerprints on the filter paper would add additional mass, leading to an overestimate of the amount of Ca2+ in the tablet.
f) This procedural error would result in an unchanged calculated mass of Ca2+ in the analyzed tablet. Selecting a new piece of filter paper and using its mass would not affect the measured mass of Ca2+ in the tablet or the accuracy of the analysis.
2) The procedure can be used to determine the number of milligrams of Ca2+ ion in a food sample, even if the Ca2+ ion is present in a form other than CaCO3, because the procedure involves reacting Ca2+ ions with Na2CO3 solution to precipitate them as CaCO3. This reaction is specific to Ca2+ ions and allows for their selective separation from other ions or compounds present in the food sample. By measuring the mass of the precipitated CaCO3, the amount of Ca2+ ions present in the food sample can be determined.
a) This procedural error would result in a higher calculated mass of Ca2+ in the analyzed tablet. This is because some of the solid was transferred along with the solution, and this solid contains Ca2+ ions which would contribute to the overall mass measured.
b) This procedural error would result in an unchanged calculated mass of Ca2+ in the analyzed tablet. The undissolved tablet pieces that were observed do not contain Ca2+ ions, so they would not contribute to the measured mass of Ca2+.
c) This procedural error would result in a lower calculated mass of Ca2+ in the analyzed tablet. The student's failure to add additional Na2CO3 solution and test the solution again would mean that any Ca2+ ions initially present in the solution were not fully reacted with the Na2CO3. As a result, fewer Ca2+ ions would be measured, leading to a lower calculated mass.
d) This procedural error would result in an unchanged calculated mass of Ca2+ in the analyzed tablet. The torn-off filter paper corner does not contain Ca2+ ions and therefore would not contribute to the measured mass of Ca2+.
e) This procedural error would result in a higher calculated mass of Ca2+ in the analyzed tablet. The wet fingerprints on the filter paper would add additional mass to the measurement, which would incorrectly be attributed to Ca2+ ions.
f) This procedural error would result in a lower calculated mass of Ca2+ in the analyzed tablet. By failing to determine the mass of the filter paper prior to filtering, the student has mistakenly omitted the mass of the filter paper from the calculations. This would lead to a lower calculated mass of Ca2+.
2) This experiment's procedure can be used to determine the number of milligrams of Ca2+ ion in a food sample even if the Ca2+ ion is present in a form other than CaCO3. This is because the procedure involves reacting the Ca2+ ions with Na2CO3, which forms a precipitate of CaCO3. The mass of this precipitate is then measured, and by using stoichiometry, the number of milligrams of Ca2+ ions can be calculated based on the known reaction and the mass of the precipitate. Therefore, the specific form in which the Ca2+ ion is present does not affect the ability to determine its quantity using this procedure.