April 30, 2024, 12:31:40 PM
Forum Rules: Read This Before Posting


Topic: comparing lattice energies (not calculation)  (Read 3080 times)

0 Members and 1 Guest are viewing this topic.

Offline bubaKazouba

  • New Member
  • **
  • Posts: 7
  • Mole Snacks: +0/-0
comparing lattice energies (not calculation)
« on: January 02, 2013, 07:11:56 PM »
this is the question:
http://i.img-share.net/sTGgfY1TB4.png

13a)
I think the answer should be C because CaO has the highest difference between the anion and cation in the ionic radii, so the anion will be more polarised, so more covalent characters so more lattice energy
but my teacher says its D I'm really confused I don't know.
---------------------
13b) I don't konw what to do about B Li2O because there are 2 Li
Please help thanks in advance :)

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27666
  • Mole Snacks: +1801/-410
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: comparing lattice energies (not calculation)
« Reply #1 on: January 03, 2013, 03:52:22 AM »
a. This is most likely purely about electrostatic interactions (so treat them all as purely ionic).

b. And this one is most likely about the least ionic character.

I don't like the question. They want you to use contradicting approaches to answer a and b.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline bubaKazouba

  • New Member
  • **
  • Posts: 7
  • Mole Snacks: +0/-0
Re: comparing lattice energies (not calculation)
« Reply #2 on: January 03, 2013, 04:23:29 PM »
thank you for your reply  :), but sorry I don't understand
what will I do if I treat them as completely ionic?

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27666
  • Mole Snacks: +1801/-410
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: comparing lattice energies (not calculation)
« Reply #3 on: January 03, 2013, 04:25:54 PM »
Lattice energy will be just a function of charges and distances (coulomb forces).
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline bubaKazouba

  • New Member
  • **
  • Posts: 7
  • Mole Snacks: +0/-0
Re: comparing lattice energies (not calculation)
« Reply #4 on: January 03, 2013, 05:06:07 PM »
Oh yeah I get it Thank you very much
but I still dont get b)

Offline souro10

  • Regular Member
  • ***
  • Posts: 92
  • Mole Snacks: +2/-21
  • Gender: Male
  • Chemistry lover
Re: comparing lattice energies (not calculation)
« Reply #5 on: January 10, 2013, 03:44:36 PM »
You have already got the answer to question (a).

For (b) , you need to find out the compound which has most covalent character. Why is Calcium Sulfide almost insoluble in water?

Sponsored Links