Answer:
Wc - Ws = 25.25 - 23.075 = 2.175 weight of water displaced
Since water has a density of 1 means the chain has a volume of 2.175 cm^3
The density of the chain is M / V = 25.25 g / 2.175 cm^3
ρc = 11.6 which is less than pure gold of 19.32
This is all that one can say about the purity of gold in the chain because one does not know the density of other material in the chain.
That means that one does not know how much pure gold is actually in the chain without knowing the density of the rest of the chain.
