Stronger bonds are more stable - do they have more energy or less?

[GomerPyle]

I am very confused and am hearing conflicting thoughts on bond energy.

So if a chemical bond is strong, it is stable. Does it have lower energy or higher energy than a weaker bond?

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[sazerac]

The answer is ambiguous and depends on your definition of lower or higher. The MCAT isn't going to nail you on obscure definitions. Just know that it takes more energy from somewhere to rip apart a stronger bond, and you will be fine I promise.

 

[nOchemallday]

I am very confused and am hearing conflicting thoughts on bond energy.

So if a chemical bond is strong, it is stable. Does it have lower energy or higher energy than a weaker bond?

Outlined here: http://forums.studentdoc...thread.php?t=218066 and here: http://forums.studentdoc...thread.php?t=579458 (Bond strength explained in last post here)

Bond Stability (Triple are closest and hardest to break = stable):
Triple>Double>Single ; however a sigma bond is more stable than pi bond
(2 pi + sigma)>(1pi + sigma)>(sigma)>(pi)

Bond Strength (in other words, "Energy required to break the bond"):
Triple>Double>Single
Again 2pi + sigma is harder to break than just a sigma bond.

Bond Length:
Single>Double>Triple

 

[GomerPyle]

Alright - thanks guys.

 

[athockey7]

I am very confused and am hearing conflicting thoughts on bond energy.

So if a chemical bond is strong, it is stable. Does it have lower energy or higher energy than a weaker bond?

and dont confuse bond energy with energy released when breaking bonds

the more energy released when breaking a bond results in more stable products from less stable reactants

the more bond energy initially in the bond the more stable.

 

[sazerac]

and dont confuse bond energy with energy released when breaking bonds

the more energy released when breaking a bond results in more stable products from less stable reactants

the more bond energy initially in the bond the more stable.

Energy is NEVER released when breaking a bond; otherwise the bond would never have formed in the first place.

 

[athockey7]

but im pretty sure ive come across solutions were it says that the most energy is released from the least stable compounds... maybe i misunderstood

 

[onedirection]

Outlined here: http://forums.studentdoc...thread.php?t=218066 and here: http://forums.studentdoc...thread.php?t=579458 (Bond strength explained in last post here)

Bond Stability (Triple are closest and hardest to break = stable):
Triple>Double>Single ; however a sigma bond is more stable than pi bond
(2 pi + sigma)>(1pi + sigma)>(sigma)>(pi)

Bond Strength (in other words, "Energy required to break the bond"):
Triple>Double>Single
Again 2pi + sigma is harder to break than just a sigma bond.

Bond Length:
Single>Double>Triple

Even easier just think about it in terms of s character

the more s character the more stable

this is because the s orbital is smaller than the p orbital, therefore electrons are closer to the nucleus making it more stable overall

 

[FeinMS]

but im pretty sure ive come across solutions were it says that the most energy is released from the least stable compounds... maybe i misunderstood

You're probably familiar with heat of hydrogenation. In that case, you're replacing C-C pi bond with more stable C-H sigma bond. This process releases energy because you're forming more stable bonds.

Always always, forming bond releases energy and breaking bond requires energy. When multiple bonds are formed and broken simultaneously, it's hard to predict without incorporating all information about bond stability

 

[surferbreh]

I am very confused and am hearing conflicting thoughts on bond energy.

So if a chemical bond is strong, it is stable. Does it have lower energy or higher energy than a weaker bond?

let's break it down now... hammer time

stronger bonds (either because they are double/triple bonded or b/c they have a shorter bond length), along with other factors, make a chemical species more "stable" (review ochem to get a grasp on stability).

Equilibrium in a reaction favors lower energy and stability. If a product is lower energy w/ respect to the reactant species, the equillibrium will shift right (it will naturally have a higher concentration of product) making it "product favored". If the reactant is lower energy, the equil. will shift left towards the reactants meaning that there will be a higher concentration of reactants.

ok, that's great, but we still have to "hammer" on...

Things that are stable are low energy (think of a rock, unmoving in the forrest).
Things that are unstable are high energy (think of an obnoxious 3yr old running around and screaming).

That being said, we still have to talk about BOND STRENGTH and the ENERGY required to break strong or weak bonds.

It's hard to break a ROCK (low energy substance) b/c its BONDS are STRONG.
It's easy to break a TODDLER (high energy substance) b/c his BONDS (relative to a rock) are WEAK.

thus, we see how a strong bond -> stable chem. species -> tough bond to break -> alot of energy is required to break a stable, low energy chemical species with strong bonds.

am I right, or am I right?

*no offense to toddler, I have 5yr old brother who I love. It's just that taboo or socially unacceptable thoughts stick in your head, so if you associate them with tricky concepts, the concepts get stuck in that head of yours with that taboo-image

 

[Janus_Kinase]

let's break it down now... hammer time

stronger bonds (either because they are double/triple bonded or b/c they have a shorter bond length), along with other factors, make a chemical species more "stable" (review ochem to get a grasp on stability).

Equilibrium in a reaction favors lower energy and stability. If a product is lower energy w/ respect to the reactant species, the equillibrium will shift right (it will naturally have a higher concentration of product) making it "product favored". If the reactant is lower energy, the equil. will shift left towards the reactants meaning that there will be a higher concentration of reactants.

ok, that's great, but we still have to "hammer" on...

Things that are stable are low energy (think of a rock, unmoving in the forrest).
Things that are unstable are high energy (think of an obnoxious 3yr old running around and screaming).

That being said, we still have to talk about BOND STRENGTH and the ENERGY required to break strong or weak bonds.

It's hard to break a ROCK (low energy substance) b/c its BONDS are STRONG.
It's easy to break a TODDLER (high energy substance) b/c his BONDS (relative to a rock) are WEAK.

thus, we see how a strong bond -> stable chem. species -> tough bond to break -> alot of energy is required to break a stable, low energy chemical species with strong bonds.

am I right, or am I right?

*no offense to toddler, I have 5yr old brother who I love. It's just that taboo or socially unacceptable thoughts stick in your head, so if you associate them with tricky concepts, the concepts get stuck in that head of yours with that taboo-image

Read with MC hammers voice to the beat of 'cant touch this'