The excess molar gibbs free energy of formation of solid solutions in the system au-cu can be represented by gxs = -28280 xauxcu (j) calculate the activities of au and cu in the alloy of xau = 0.5 and 900k.

The answer is b on plato.

There is no reason to think the results are biased or not conducted properly but you should not assume the results are correct just because they were done in a laboratory so the answer would be c. it is likely to be reliable because the results support the conclusion presented.