Thermodynamics of Reactions with Glucose

[xsc614]

Homework Statement

Homework Equations

ΔH rxn = ΔH products - ΔH reactants
ΔU = q + w

The Attempt at a Solution

Pretty overwhelmed with the entire problem. Since the ΔH's of all reactants and products were in the literature for the reference temperature of 298.15 K, I was able to plug them in and get the value for that temperature. I am not sure how it changes with temperature increase?

Can anyone point me in the right direction?

 

[chemisttree]

Perhaps heat capacity(-ies) is the reason where delta T = 298.15 K - 330.15 K.

 

[xsc614]

Ah, okay I was able to the the change in enthalpy for 330.15 K by Hess's law, and adding delta H rxn (298.15K) to the integral of delta Cp dT integrated from To to T.

Now I'm stuck on b. part ii. I can't find any examples anywhere on calculating problems like this and my professor is so highly educated (MIT, Harvard, UPenn) that I can't understand him.

Ahh, any help is appreciated!

 

[chemisttree]

It lies somewhere in Table 4.1 and 4.2. That will get you started.

 

[DeeNos]

As a scientist, it is important to understand the thermodynamics of reactions involving glucose as it is a key molecule in many biological processes. In this homework problem, the relationship between enthalpy (ΔH) and internal energy (ΔU) is important to consider. The equation ΔU = q + w tells us that internal energy can change due to heat (q) and work (w). In the case of a reaction with glucose, heat can be released or absorbed (exothermic or endothermic) and work can be done on or by the system.

To solve this problem, you correctly used the equation ΔH rxn = ΔH products - ΔH reactants, where ΔH rxn is the change in enthalpy for the reaction. This equation allows us to determine whether the reaction is exothermic or endothermic. However, it is important to note that the values of ΔH for reactants and products may change with temperature. This is because the energy required to break and form chemical bonds can vary with temperature.

To account for this temperature dependence, we can use the equation ΔH(T2) = ΔH(T1) + ΔCp(T2 - T1), where ΔCp is the change in heat capacity of the system between temperatures T1 and T2. This equation allows us to calculate the enthalpy at a different temperature (T2) using the enthalpy at a reference temperature (T1) and the change in heat capacity.

In conclusion, understanding the thermodynamics of reactions involving glucose is essential for understanding the energetics of biological processes. To fully analyze these reactions, it is important to consider the temperature dependence of enthalpy and internal energy.