Instructions 2.Experimental – approximately half a typed page. You are to include experimental steps you have taken in conducting the experiment, such that the reader can repeat the experiment by following instructions given in this section. However, there is no need to include lengthy description on preparation of solutions provided to you. 3. Results and Discussion (you are to present results in the Results section, followed by a discussion and/or comments on the results in the Discussion section). (a) Tabulate all titration results in a table with appropriate units shown in each column. (b) Using your own results, calculate the mean, standard deviation and relative standard deviation of the titres in each of the three assays above. Based on an appropriate stoichiometric ratio, you are able to work out the number of moles of Al3+, Ca2+ and Mg2+ present in the titration experiments. You should subtract moles of Al3+, Ca2+ and Mg2+ present in the blank solutions from the total to obtain the true number of moles present in the sample. Next, calculate the number of moles of Al3+, Ca2+ and Mg2+ present in the sample weighed out in the beginning of the experiment. A sketch shown for Ca2+ assay below may help you analyse steps required in your calculations. Next, determine the percentage weight (i.e. concentration) of Al3+ and that of individual Ca2+ and Mg2+ in the antacid sample. You can ignore calculating the standard deviations of the percentage weights. (c) Use the mean and standard deviations from part (b) to calculate the 95% confidence intervals for the mean titres Al3+, Ca2+ and Mg2+ of future antacid batches. (d) For each assay above, how many titrations should you perform if you wish to be 95% confident to have an estimated bias within ±0.05? (e) Based on the stipulated values, estimate the percentage weight of Al3+ and that of individual Ca2+ and Mg2+ (note we are to calculate the percentage weight of ions here, not the compounds) in the antacid sample. Compare and comment on the results estimated in (b) and (e). [Note: when you are asked to make a comparison, do not simply report that one result is higher/lower than the other, which is obvious when we examine two numbers. Instead, you should comment on what could have happened during the experiment, giving rise to such a difference.] You can use the percentage difference between your experimental value and the stipulated value for each ion as a guide in making your comparison. Comment on all relevant errors encountered in this experiment. If necessary, classify them under the headings “Determinate Errors”, “Indeterminate Errors” and “Gross Errors”. Caution: Be careful of the distinctions among “errors”, “mistakes” and “carelessness”. 4. Conclusions – no more than half a typed page.