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Delta H and Delta G

Posted: Sat Mar 14, 2020 11:28 am
by ShravanPatel2B
When given multiple chemical equations how do we determine in which one the values for delta h and delta g are the most similar. This relates to problem 6b in the midterm. Thanks

Re: Delta H and Delta G

Posted: Sat Mar 14, 2020 1:43 pm
by Chem_Mod
It is difficult to tell for deltaH alone without knowing the bond enthalpies or heat of formations of the species that are involved (but you should know that strong acids dissociating in water always have a negative deltaH). For deltaG, you can look at the change in the number of moles of gas between reactants and products. In problem 6b, the first equation has 4 moles of gas to 4 moles of gas, a 0 mole change in the number of moles of gas. The only reaction that also has a change of 0 in terms of moles of gas is A, 0 moles of gas to 0 moles of gas.