Answer
75% Au
Work Step by Step
One mole of atoms contains 6.022x10^23 atoms.
2.49 x 10^23 / 6.022x10^23 = 0.4135 mole of atoms.
1 mole of gold = 197.0 g
1 mole of palladium = 106.4 g
mole Au + mole Pd = 0.4135
mole Au x 197 + mole Pd x 106.4 = 67.2
Two equations in two unknowns
mole Au = 0.2561
mole Pd = 0.1574
grams Au = 0.2561 x 197 = 50.45 g
50.45 / 67.2 = 0.75 (75% Au)
