The balanced chemical equation for the reaction between copper and sulfur to form copper sulfide (Cu2S) is:
2Cu + S → Cu2S
According to the equation, two moles of copper react with one mole of sulfur to form one mole of copper sulfide.
To find the theoretical mass of Cu2S that can be produced from 36.25 grams of copper, we need to first convert the mass of copper to moles using its molar mass:
moles of Cu = 36.25 g / 63.55 g/mol = 0.5708 mol
Since two moles of copper react with one mole of sulfur to form one mole of Cu2S, we know that the number of moles of Cu2S formed will be half the number of moles of copper used:
moles of Cu2S = 0.5708 mol / 2 = 0.2854 mol
Finally, we can use the molar mass of Cu2S to convert the number of moles to mass:
mass of Cu2S = 0.2854 mol x 159.16 g/mol = 45.45 g
Rounding to three significant figures, the theoretical mass of Cu2S that can be produced is 45.5 grams