<h2>Number of moles= Given mass/Molar mass of gold
</h2>
Molar mass of gold= 196.97 g/mol.
By substituting we get(57.01 g Au) / (196.97 g/moles) = 0.2894 moles Au
Hence we get number of moles=0.2894 moles Au
<u>Note: </u>Molar mass= Mass of the sample of a compound/Total amount of that substance in that sample. Molar masses of different substances are the standard value which are specifically arranged to each compound
A). Calculation: Given mass of Au * 1mol of Au/molar mass of Au= # of moles
;
57.01 g Au*1 mole of Au/196.97g Au=0.3 moles of Au. So the answer is 0.3 moles of gold(Au). Good luck on the rest, and message me on Brainly if you need more help. I'll be happy to.