# Finding change in free energy, enthalpy and entropy

Could you take a look at some problems that I have answered to see if I'm in the right direction.

(a) Using this plot, estimate the enthalpy and entropy of binding for each protein to DNA.

(b) What is the free energy change for the binding of WT1 and EGR1 to DNA at 25oC?

(a) For each of the proteins: is the binding to DNA driven by entropy or enthalpy or both?

© BrainMass Inc. brainmass.com October 16, 2018, 3:58 pm ad1c9bdddfhttps://brainmass.com/chemistry/energetics-and-thermodynamics/finding-change-in-free-energy-enthalpy-and-entropy-9881

#### Solution Preview

To calculate delta_H and delta_S for the two proteins, its enough to just calculate the slope and the y intercept for each graph.

For calculating the slope, we have the formula,

slope = change in y/change in x = dy/dx

Here, from the graph, we cannot find the exact values for dy and dx as the points are not clear. But its a very simple calulation which you can easily do.

Having ...

#### Solution Summary

The solution explains each step and provides all mathematical steps.

Chemical Thermodynamics : Enthalpy, Entropy and Gibbs Free Energy

Consider acetic acid, CH3COOH, The active ingredient in vinegar. It is also responsible for the sour taste of wine when gets exposed to air. Bacterial oxidation turns alcohol to acid.

C2H5OH (aq) +O2 → CH3COOH (aq) +H2O

The following data may be useful:

C2H5OH (aq): ∆H˚f = -288.3 kJ/mol

S˚= 145.5 J/mol.k

CH3COOH (aq): ∆H˚f = -485.8 kJ/mol

S˚= 178.7 J/mol.k

(a)Calculate ∆H˚ and ∆ S˚ for this process.

(b)Is the reaction spontaneous at 25˚ C? At 4˚ C?

(C)The heat of vaporization for acetic acid is 24.3 kJ/mol. Its normal boiling point is 118.5 ˚ C Calculate ∆ S˚ for the reaction.

CH3COOH (l) → CH3COOH(g)

(d)What is the standard molar entropy for CH3COOH (g), taking S˚ for CH3COOH (l) to be 159.8 J/mol.K?

(e)Calculate ∆G at 25˚C for the formation of acetic acid from ethanol (see raction above)when (CH3COOH)=0.200M,PO2=1.13 atm , and (C2H5OH)=0.125M.

(f)Calculate ∆G˚ for the ionization of acetic at 25˚C (Ka = 1.8*10^-5)