[uclabruin]

Hello,

I am not taking a Chemistry course at the moment, but I plan to, and in preparation I've been reading through this book:
http://www.ck12.org/flexbook/book/808

It seems quite good for a free book, but I've encountered what I think might be an error, can someone help me out?

The chapter on covalent bonds contains some very confusing statements about bond energy, bond strength, and bond stability.

Bond energy:
"Bond energy is the amount of energy necessary to break the covalent bond"

OK, so bond energy should be directly proportional to bond stability.  And indeed it is:

"Stable compounds have high bond energy and unstable compounds have low bond energy"

Whereas bond energy STATE should be inversely proportional to bond stability.  And indeed it is:

"Low energy state bonds are stable and have high bond strength"

All good so far.  But then comes this:

"Molecules with high bond energy have weak bonds.  They did not release much energy when they formed and so not much energy is needed to break the molecules back apart.  High bond energy means low bond strength."

WTF?  So bond strength is INVERSELY proportional to bond energy and INVERSELY proportional to bond stability?

What the heck is the definition of bond strength, then?

I can see obviously see how bond strength would be inversely proportional to bond energy STATE.  But how can bond strength be inversely proportional to bond energy??  And how can it be inversely proportional to bond stability??

Furthermore, how can I reconcile the statement "Bond energy is the amount of energy necessary to break the covalent bond" with the statement "Molecules with high bond energy...did not release much energy when they formed and so not much energy is needed to break the molecules back apart."

I feel certain that the book has made a mistake, but until I know that the mistake is, I can't know how bond energy, strength, & stability are ACTUALLY related to each other.

Intuitively, here is what I would assume the relationships to be:
Bond energy ---dir. proportional---> bond strength, bond stability
Bond energy state ---ind. proportional---> bond strength, bond stability
Bond energy ---ind. proportional---> Bond energy state


Thanks.

[Borek]

But then comes this:

"Molecules with high bond energy have weak bonds.  They did not release much energy when they formed and so not much energy is needed to break the molecules back apart.  High bond energy means low bond strength."

Kudos to you for catching such things, that means you are really involved in understanding the thing you are reading.

An obvious mistake. I have some vague ideas about where this confusing statement could come from, but it doesn't matter much. Stay with the initial definition.

Have you tried to contact ck12? They have a feedback link in the page footer.

[uclabruin]

An obvious mistake. I have some vague ideas about where this confusing statement could come from, but it doesn't matter much. Stay with the initial definition.

Have you tried to contact ck12? They have a feedback link in the page footer.

Thank you for the reply.  So, just to be clear, strength and stability, if not quite synonyms, are very similar and are directly proportional to each other?  And both strength and stability are directly proportional to bond energy but inversely proportional to bond energy state?

I haven't tried contacting them, but perhaps I should.  Up until this point, I've been impressed with the book.  In fact, I was probably only able to catch the mistake because the book has been so good up until now about stressing the difference between bond energy and bond energy state, and driving home the point that chemical reactions occur because they release energy (much like potential energy in physics).

Thanks again!

[uclabruin]

I notified them about the mistake and linked to this page.  Apparently, they've already fixed the mistake about one business day later!  Ah, the joys of a completely digital book.

http://www.ck12.org/flexbook/pdf/a872b04e6d19df407979458f70fe9635.pdf CK-12 Chemistry PDF
http://www.ck12.org/flexbook/liveview/a872b04e6d19df407979458f70fe9635.html CK-12 Chemistry HTML Link
 
http://www.ck12.org/flexbook/pdf/fe6588c98dc2ec3c2ec7ad14c9921878.pdf  CK-12 Chemistry Second Edition PDF
http://www.ck12.org/flexbook/liveview/fe6588c98dc2ec3c2ec7ad14c9921878.html  CK-12 Chemistry Second Edition

HI uclabruin,
 
Thanks so much for identifying, recording, and providing your helpful corrections regarding the errata in CK-12's Chemistry resource.
 
We greatly appreciate your time, your thoughtful process in identifying, researching, and confirming the mistake via the forum, and for providing us with the rationale and exact location of errata within the content.  
 
We've corrected the errors and reimported the updates into the Chemistry FlexBook.  We've attached the newly imported PDF/HTML Links for the Chemistry FlexBook (links attached above).
 
I've also included the CK-12 Chemistry Second Edition PDF/HTML Links in case you are interested in the revised version of the FlexBook (links attached above).
 
Please know we are in the process of creating two new Chemistry FlexBooks - a Basic version and an Intermediate - Honors version.  Anticipated completion is June 2012 - we'd love to provide your with our new resources if you are interested.
 
Take care, and thanks so much again for helping us improve our content.
 
All the best,

[uclabruin]

double post again, sorry