can you please show me the steps of how to get the excess reactant

23.903 grams of product is produced
816.56grams of excess reactant was left over
The reaction between copper solid and sulfur is expressed as:
[tex]Cu(s)+S\rightarrow CuS[/tex]Determine the moles of copper
[tex]\begin{gathered} moles\text{ of Cu}=\frac{7.89\times10^{24}}{6.02\times10^{23}} \\ moles\text{ of Cu}=1.31\times10 \\ moles\text{ of Cu}=13.1moles \end{gathered}[/tex]Determine the moles of sulfur
[tex]\begin{gathered} moles\text{ of S}=\frac{8g}{32} \\ moles\text{ of sulfur}=0.25moles \end{gathered}[/tex]Since sulfur has less moles, hence sulfur is the limiting reactant
Calculate the mass of CuS
Mass = moles * molar mass
Mass of CuS = 0.25 * 95.611
Mass of CuS = 23.903 grams
Determine the mass of excess reactant consumed
[tex]\begin{gathered} Mass\text{ of Cu}=moles\times molar\text{ mass} \\ Mass\text{ of Cu}=0.25\times63.546 \\ Mass\text{ of Cu}=15.8865gram\text{ \lparen mass used up\rparen} \end{gathered}[/tex]Mass of Cu started with = 13.1 * 63.546
Mass of Cu started with = 832.4526grams
Mass of excess reactant left over = 832.4526g - 15.8865g
Mass of excess reactant left over = 816.56grams
Therefore 816.56grams of excess reactant was left over