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Thread: Chemistry Lab Help (full rep)

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    GOAT's Avatar
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    Chemistry Lab Help (full rep)

    A student grinds up an antacid tablet that weighs 1.42 grams. The antacid contains CaCO3 as the primary active ingredient. The resulting powder is added to 15.00 mL of 1.00 M HCl solution. The mixture is then heated, cooled, and titrated with 0.950 M NaOH solution from a buret. The initial buret reading is 7.85 mL; at end point, the buret reading is 13.65 mL.

    6. Calculate the initial number of moles of HCl in 15.00 mL of the 1.00 M HCl solution. (3 sig figs)


    7. Calculate the number of moles of EXCESS HCl that were left over after the antacid tablet was used up and then neutralized by the NaOH solution in the titration.


    8. Calculate the number of moles of HCl that were used up (neutralized) by the antacid.


    9. Calculate the number of moles of HCl neutralized per gram of antacid.


    10. The balanced reaction of the active ingredient with HCl is: 2 HCl + CaCO3 ---> CaCl2 + CO2 + H2O. Calculate the mass of the active ingredient in the tablet.


    11. If a box of the antacid used in the example above costs $2.38, contained 75 tablets and the average mass of the tablet is 1.42 g/tablet, what is the cost of the antacid in ˘ per tablet and in ˘ per gram?

    Please and thank you!

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    was going to do this but too many questions

    are you really having difficulty or do you just want someone to do your homework?

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    A little of both. I am continually swamped with work so there are times that I simply run out of times to do things. Just for Tuesday and Wednesday I have a 6-7 page essay to write, 2 lab reports to write, worksheets, studying for an exam, assignments, and many other things. The thing with this though, it's just very frustrating and I constantly feel like I am just going to snap soon...

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    alien's Avatar
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    A student grinds up an antacid tablet that weighs 1.42 gram. The antacid contains CaCO3 as the primary active ingredient. The resulting powder is added to 15.00 mL of 1.00 M HCl solution. The mixture is then heated, cooled, and titrated with 0.950 M NaOH solution from a buret. The initial buret reading is 7.85 mL; at end point, the buret reading is 13.65 mL.

    6. Calculate the initial number of moles of HCl in 15.00 mL of the 1.00 M HCl solution.
    (Ans. 0.0150 moles HCl before tablet was added)

    7. Calculate the number of moles of excess HCl that were left over after the antacid tablet was used up. To do this you must first calculate the moles of NaOH used to in the titration. Then convert moles NaOH to moles HCl using the stoichiometric ratio of HCl/NaOH found in the balanced reaction equation.
    (Ans. 0.00551 moles HCl left after tablet was added)

    8. Calculate the number of moles of HCl that were used up (neutralized) by the antacid. (Ans. 0.00949 moles HCl neutralized by the tablet)

    9. Calculate the number of moles of HCl neutralized per gram of antacid. (Ans. 0.00668 moles HCl/g)

    11. A box of the antacid used in the example above costs $2.38, contains 75 tablets and the tablets have an average mass of 1.42 g/tablet. What is the cost of the antacid in ˘ per tablet and in ˘ per gram? (Ans. 3.17 ˘ per tablet and 2.23 ˘ per gram)

    I found this as is on google, so you don't have to rep me xD answer to number 10 is missing though.
    Source: http://www.learningace.com/doc/10520...7e4f5/f1prelab

    wait, this might not even be useful because the calculations aren't shown. oh well, hope someone else can help. I'd try solving these myself but I'm busy studying for an exam. :{
    (I think the answer to 10 might be "0.75g" but I'm not sure!)
    Last edited by alien; 11-03-2013 at 04:10 AM.

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    Yeah unfortunately I found that as well but I need to show work...oh well I guess I just won't watch football today and spend today working. Fun... :/

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