# Esimating delta S and delta H from temp and Kb

• chazgurl4life

#### chazgurl4life

The relationship between free energy and the equilibrium constant is

Go = -RT ln K

By measuring the pH at various temperatures, the Kb for NH3(aq) was found to be temperature dependent, yielding the following values:

temperature (K) Kb
283 1.34 X 10-5
293 1.42 X 10-5
303 1.50 X 10-5

Over moderate temperature ranges (ranges less than 100 K degrees) both deltaSo and deltaHo can be considered approximately temperature independent. By plotting the available information appropriately, obtain estimates for deltaSo and delayHo for the reaction:

ok so i figured out that my y=mx+b equation should loook lik:

lnKb=delta H/R(gas constnt) - delta S/r

bbut what is my x-axis and y axis?

ok so i figured out that my y=mx+b equation should loook lik:

lnKb=delta H/R(gas constnt) - delta S/r

delat g=delta H-Temp(delta S)

You lost a factor of T in your enthalpy term. By restoring that, you can find a linear relationship between a function of ##K## and a function of ##T##, which will allow you to read off the enthalpy and entropy directly from a graph of the data.