If one Tums tablet contains 550. mg of this ingredient and a person takes two tablets a day, how many calcium ions does this person obtain from...

The active ingredient in Tums is calcium carbonate. If a person takes two 550 mg tablets in one day, they have taken 550*2 = 1100 mg of the active ingredient. 

The chemical formula for calcium carbonate is CaCO3. When calcium carbonate ionizes, each molecule separates into one calcium ion and one carbonate ion. So we need to determine how many molecules of calcium carbonate are present in 1100 mg.

To do so, we need to look up the molar mass of calcium carbonate, which is listed as 100.0869 g/mol. One mole contains 6.022 X 10^23 molecules.

First we convert from milligrams to mols, and then from moles to number of molecules, as follows:

1100 mg = 1.1 g

`1.1/100.0869=0.01099 mol`

`0.01099*6.02*10^23= 6.616*10^21`  molecules

Thus, the person will obtain 6.616 X 10^21 calcium ions from the tablets, since one calcium ion is present for every molecule.