Answer: 0.0706mol
Explanation:
1mole of any substance contains 6.02x10^23 atoms as proposed by Avogadro's hypothesis.
From this hypothesis,
1mole of Au = 6.02x10^23 atoms.
Therefore Xmol of Au contain 4.25 x 10^22 atoms i.e
xmol of Au = 4.25 x 10^22 / 6.02x10^23
= 0.0706mol
