What is the overall standard free-energy change for the following two reactions?

A + B-->2C äG = äG1
C + D-->E äG = äG2

a)äG1 + äG2
b)äG1 + 2äG2
c)äG2 – äG1
d)2äG2 – äG1
e)äG1äG22

A + B ==> 2C.....dG1

2C + 2D ==> 2D...2dG2
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Adding gives me dG1 + 2dG2.

To determine the overall standard free-energy change for the given reactions, we need to consider the principles of thermodynamics. The standard free-energy change (ΔG) is a measure of the overall spontaneity of a reaction.

The standard free-energy change for a reaction can be determined by summing up the individual free-energy changes for each reaction involved. In this case, we need to calculate the sum of ΔG1 and ΔG2.

Answer: a) ΔG1 + ΔG2