May 31, 2020, 02:16:26 AM
Forum Rules: Read This Before Posting


Topic: Arrrrr very basic problem, yet confused.  (Read 3336 times)

0 Members and 1 Guest are viewing this topic.

Offline Zoloft

  • Regular Member
  • ***
  • Posts: 29
  • Mole Snacks: +0/-0
Arrrrr very basic problem, yet confused.
« on: February 08, 2009, 06:45:58 PM »
According to one of my labs, the atomic mass of Zinc can be determined by the balanced equation,

Zn + 2HCl ---> H2 + ZnCl2

Then it says "the number of moles of zinc metal that reacted be be calculated"

So then I use the number of moles of H2 that I calculated (we did a barometric experiment and calculated moles of H2,n, from n = PV/RT) and I do:

.00581 mol H2 x (1 mol Zn / 1 mol H2) = .00581 mol of Zn

then it says "Since all the original Zinc is consumed in this reaction, the atomic mass of zinc can thereby be determined..."

My question is, how do I determine this?

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 25773
  • Mole Snacks: +1686/-400
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Arrrrr very basic problem, yet confused.
« Reply #1 on: February 08, 2009, 07:11:57 PM »
I suppose you know mass of zinc used?
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Offline Zoloft

  • Regular Member
  • ***
  • Posts: 29
  • Mole Snacks: +0/-0
Re: Arrrrr very basic problem, yet confused.
« Reply #2 on: February 08, 2009, 07:20:59 PM »
I suppose you know mass of zinc used?
Yes, it was .587 grams.

Obviously the Atomic mass is 65.41 g, but how do I determine this (or a number close to this) using the experimental procedure?

Offline nj_bartel

  • Sr. Member
  • *****
  • Posts: 1487
  • Mole Snacks: +76/-42
Re: Arrrrr very basic problem, yet confused.
« Reply #3 on: February 08, 2009, 08:03:40 PM »
MWZinc = x gramsZinc / 1 moleZinc

grams / moles

Offline Zoloft

  • Regular Member
  • ***
  • Posts: 29
  • Mole Snacks: +0/-0
Re: Arrrrr very basic problem, yet confused.
« Reply #4 on: February 08, 2009, 08:14:40 PM »
MWZinc = x gramsZinc / 1 moleZinc

grams / moles

Hmmm, so in this case the number of moles of Zinc is the moles of Zinc using the stoichiometric relationship, right?


Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 25773
  • Mole Snacks: +1686/-400
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Arrrrr very basic problem, yet confused.
« Reply #5 on: February 09, 2009, 02:51:17 AM »
Try to devise a scenario in which it is not.
« Last Edit: February 09, 2009, 05:26:40 AM by Borek »
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Sponsored Links