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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Forces42 on May 07, 2009, 03:21:59 AM

Title: Neutralizing stomach acid
Post by: Forces42 on May 07, 2009, 03:21:59 AM: A Rolaids tablet contains calcium carbonate which neutralizes stomach acid. If a Rolaids tablet neutralizes 42.15 mL of .0320 M hydrochloric acid how many milligrams of calcium carbonate are in Rolaids tablet?

CaCO₃ + 2HCl -> CaCl₂ + H₂O + CO₂

this is what I have

42.15 mL sol'n x .320 M HCl/1000 mL sol'n x 1 mol CaCO₃/2 mol HCl = 0.00674 mol CaCO₃

my trouble is with finding milligrams of calcium carbonate I am not sure what comes next?

0.00674 mol CaCO₃ / 1000mg
Title: Re: Neutralizing stomach acid
Post by: nj_bartel on May 07, 2009, 03:31:59 AM: figure out the number of grams in one mole, multiply that by 1000 mg per gram, multiply that by the number of moles you have (which you already figured out).
Title: Re: Neutralizing stomach acid
Post by: Forces42 on May 07, 2009, 03:50:46 AM: Is this how it should look

0.00647 mol CaCO₃ x 100.09g CaCO₃ / 1 mol CaCO₃ x 1000 mg/ 1 g = 648 mg of calcium carbonate
Title: Re: Neutralizing stomach acid
Post by: Borek on May 07, 2009, 04:05:22 AM: Quote from: Forces42 on May 07, 2009, 03:21:59 AM
.0320 M hydrochloric acid

Quote
.320 M HCl

Which one is correct?

Quote from: Forces42 on May 07, 2009, 03:21:59 AM
0.00674 mol CaCO₃

Quote from: Forces42 on May 07, 2009, 03:50:46 AM
0.00647 mol CaCO₃

Watch out.
Title: Re: Neutralizing stomach acid
Post by: AWK on May 07, 2009, 04:08:07 AM: Quote
42.15 mL sol'n x .320 M HCl/1000 mL sol'n x 1 mol CaCO3/2 mol HCl = 0.00674 mol CaCO3
Where you taken into account that CaCO₃ reacts with 2 moles of HCl?
Title: Re: Neutralizing stomach acid
Post by: Forces42 on May 07, 2009, 04:30:36 AM: okay it is 0.320 M HCl

opps thanks, it should be 0.00674

0.00674 mol CaCO3 x 100.09g CaCO3 / 1 mol CaCO3 x 1000 mg/ 1 g = 675 mg of calcium carbonate
Title: Re: Neutralizing stomach acid
Post by: Borek on May 07, 2009, 04:34:42 AM: Quote from: AWK on May 07, 2009, 04:08:07 AM
Quote
42.15 mL sol'n x .320 M HCl/1000 mL sol'n x 1 mol CaCO3/2 mol HCl = 0.00674 mol CaCO3
Where you taken into account that CaCO₃ reacts with 2 moles of HCl?

Yes he did :)
Title: Re: Neutralizing stomach acid
Post by: Borek on May 07, 2009, 04:36:04 AM: Quote from: Forces42 on May 07, 2009, 04:30:36 AM
675 mg of calcium carbonate

OK
Title: Re: Neutralizing stomach acid
Post by: Forces42 on May 07, 2009, 04:49:57 AM: Yes he did :)
[/quote]

P.S. you assume I'm a he ;)

Thank you for the help.
Title: Re: Neutralizing stomach acid
Post by: Borek on May 07, 2009, 09:24:01 AM: Quote from: Forces42 on May 07, 2009, 04:49:57 AM
Quote
Yes he did :)

P.S. you assume I'm a he ;)

Wrongly? Set your sex in your forum configuration :)