Find mass of Ca (mg/tablet)? I need to know how to do this I have the answer but

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Find mass of Ca (mg/tablet)? I need to know how to do this I have the answer but do not know how to do it. Also if Relative error and absoute error could be shown too that would be great! The procedure was

1.  Remove your crucibles from the oven and place in a desiccator to cool. You will need to determine the mass ofeach crucible at some point prior to the filtration steps below. This can be done while you are waiting for theprecipitation reaction described below to take place. Since a positive bias can result from oils on the hands, donot handle crucibles with bare hands after weighing.2.  Obtain one antacid tablet and determine its mass. Record its brand and any other observations about the tabletas well as the reported mass of calcium in each tablet.3.  Calculate the mass of tablet required to obtain approximately 30 mg of calcium based on the nominal mg Calisted on the package.4.  Crush the tablet and grind with a ceramic mortar and pestle to homogenize the sample.5.  Transfer the calculated mass of tablet to a 100 mL beaker. Repeat this to provide a total of 3samples in separatebeakers.6.  Add 8 mL of 0.45 M HCl to each beaker. 7.  If the tablet does not completely dissolve, boil the samples for 5 minutes. If necessary, add 0.45 M HCl toprevent the sample from boiling dry. If any solids remain in the sample, filter it using a Buchner funnel (withfilter paper) on a clean side-arm filter flask with vacuum pressure. Rinse with a few mL of 0.45 M HCl.Transfer the solution back to a 100 mL beaker. Rinse the filter flask with a small amount of 0.45 M HCl andtransfer the rinse to the beaker as well. Repeat this process for each sample. NOTE: you must change the filterpaper and clean the filter flask between samples.8.  Add approximately 20 mL of 0.1 M HCl to each beaker to make the total volume of sample about 25 - 30 mL

CALCIUM ANALYSIS

2

Antacid Brand Reported Calcium from bottle (mg/tablet) Mass of tablet (g) TUMS 300 1.4500 Mass of Mass of antacid weighted (g) 0.1850 0.1930 0.1590 Mass of dry crucible (g) 25.2010 23.1120 25.1100 Mass of Ca (mg)/tablet 275.0 286.3 287.5 282.9 6.9 17.1 6% Mass of Mass of product (mg) Ca (mg) crucible and roduct 25.3290 23.2510 25.2250 128.0 139.0 115.0 35.09 38.11 31.53 Average (mg)Tablet SD Abs Error (mg) Rel Error %

Explanation / Answer

To obtaint the mass of Ca(in mg/table, first divide the mass of table with the mass of the antacid used:

0.185 g / 1.45 g/tablet = 0.12758621 tablet

mass of Ca (mg/tablet) = 35.09 / 0.12758621 = 275.03 mg/tablet

Now when you get the average of the mass, you'll get the SD:

m avg = 275+286.3+287.5 = 282.93

SD = [(282.9-275)2 + (282.9-286.3)2 + (282.9-287.5)2 / 3-1]1/2

SD = 6.8967

Abs Error = 300 - 282.9 = 17.1 mg

Rel Error = 17.1 / 282.9 * 100 = 6.04%

Hope this helps

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