really quick question on bond strength

[t35t]

in an endothermic reaction:

"which will be stronger, the bonds in the products or reactants?" explain your answer

I wrote the reactants because it should be more stable and therefore should have less potential chemical energy stored inside the bonds (e.g. its harder to disrupt the bonds of carbon dioxide than disrupting the bonds of glucose (?))
the answer however states that its the product because energy has been absorbed. Is this a mistake?

[diligent18]

According to my understanding..

Bonds in the reactants will be stronger.

Bonds in the products will be less stable, bonds will be weaker.

I believe it is a mistake.  It did specify "bonds in the products/reactions" after all.

[aishuwa1995]

If you look at photosynthesis and the energy profile for it, the products have stronger bonds than the reactants. This is because products are found above the reactants in the energy profile meaning the energy stored in the bonds are greater in the products

EDIT: stronger bonds have more energy?

[diligent18]

If you look at photosynthesis and the energy profile for it, the products have stronger bonds than the reactants. This is because products are found above the reactants in the energy profile meaning the energy stored in the bonds are greater in the products..I hope that makes sense 

EDIT: stronger bonds have more energy

Energy stored in the bonds VS Strength of the bond. Different?
I was taught that the lower the energy of the reactant/product, the more stable, the stronger the bonds within the reactant/product.

Edit: In photosynthesis, are the bonds easier to break in glucose and O2 (high energy) or H20 and CO2 (lower energy)?

[aishuwa1995]

If you look at photosynthesis and the energy profile for it, the products have stronger bonds than the reactants. This is because products are found above the reactants in the energy profile meaning the energy stored in the bonds are greater in the products..I hope that makes sense 

EDIT: stronger bonds have more energy

Energy stored in the bonds VS Strength of the bond. Different?
I was taught that the lower the energy of the reactant/product, the more stable, the stronger the bonds within the reactant/product.

I'm probably wrong, don't worry but I'm confused...how does that work?

[diligent18]

I'm probably wrong, don't worry but I'm confused...how does that work?

TBH I'm not 100% certain either. It's an interesting question.
I'll have a scavenge through my notebook and see if I have something about it.

[aishuwa1995]

I'm probably wrong, don't worry but I'm confused...how does that work?

TBH I'm not 100% certain either. It's an interesting question.
I'll have a scavenge through my notebook and see if I have something about it.

haha, you're right 

If the reactants have weak bonds, while the products have strong bonds then the reaction is exothermic (enthalpy change < 0). There is a small amount of energy needed to break the bond (smaller bond energy) and a bigger energy released when strong bonds form. A negative enthalpy  change means that the system released energy.

If the reactants have strong bonds, but the products have weak bonds its an endothermic reaction. (enthalpy change > 0). The energy required to break the reactant bonds is greater than the energy released when the product bonds form.

Found this on http://chemwiki.ucdavis.edu/Theoretical_Chemistry/Chemical_Bonding/General_Principles/Bond_Energies#Average_Bond_Energy

[LeviLamp]

The simple rule for this is that the highest point on the energy profile diagram is where the reactants, or activated complex as it will be at this point, are the least stable, and the lowest point is where they are the most stable. Exothermic reactions display a higher level of stability in products, and endothermic reactions display a higher level of stability in reactants. Endothermic reactions result in a net gain of energy; all this absorbed energy now inside the products very clearly results in reduced product stability. If the book says otherwise then you should feel good for knowing that you've got a better understanding of the concept than the authors do

[Tonychet2]

reactants because by looking at the graph u can see they require more energy to break the bonds


(the activation energy for the forward reaction is higher than the backwards reaction)