April 26, 2024, 04:10:57 PM
Forum Rules: Read This Before Posting


« previous next »
Pages: [1]   Go Down

Topic: determining the number of moles?  (Read 4133 times)

0 Members and 1 Guest are viewing this topic.

Offline whittfred

  • New Member
  • **
  • Posts: 7
  • Mole Snacks: +0/-0
determining the number of moles?
« on: August 14, 2007, 09:33:17 AM »
can someone please help with this question?  "Determine the number of moles of CaCl2 in 38.0g of CaCl2-"
Logged

Offline Yggdrasil

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 3215
  • Mole Snacks: +485/-21
  • Gender: Male
  • Physical Biochemist
Re: determining the number of moles?
« Reply #1 on: August 14, 2007, 06:31:19 PM »
Divide the mass by the molecular weight of CaCl2.
Logged

Offline whittfred

  • New Member
  • **
  • Posts: 7
  • Mole Snacks: +0/-0
Re: determining the number of moles?
« Reply #2 on: August 14, 2007, 07:44:28 PM »
I get 2.92mol is this correct?
Logged

Offline constant thinker

  • mad scientist
  • Sr. Member
  • *****
  • Posts: 1275
  • Mole Snacks: +85/-45
  • Gender: Male
Re: determining the number of moles?
« Reply #3 on: August 14, 2007, 09:15:05 PM »
No, you did it backwards.

Molecular weight of CaCl2 is 110.9834.

I got about .34mols CaCl2.

Quick way.
38/110.9834=.34

Way that shows more.
38g CaCl2 * (1 mol/110.9834g)
grams cancels and you're left with mols CaCl2
38*(1/110.9834)=.34
.34 mols CaCl2
Logged
"The nine most terrifying words in the English language are, 'I'm from the government and I'm here to help.' " -Ronald Reagan

"I'm for anything that gets you through the night, be it prayer, tranquilizers, or a bottle of Jack Daniels." -Frank Sinatra
Pages: [1]   Go Up
« previous next »
Sponsored Links