Question

7. What is the mass of oxygen combine with 15.76 g of gold in a sample of gold oxide, AuO2?

Answer 1

Molar mass of $O_2=16g/mol$

Molar mass of $Au=196.96g/mol$

Total molecular mass $=196.97+(16\times 2)=228.67g/mol$

Mass of Gold in the sample$=15.76g$

Mole ratio $=1:2$

$=15.76\times2=31.52$

$=$ $228.67\over 31.52$$=7.25g$