Question

Question #ca9c5

Answer 1

Approx. `103*g`

Explanation:

`"Moles of copper"` `=` `(82*g)/(63.55*g*mol^-1` `=` `1.29*mol`.

`"Moles of sulfur"` `=` `(25*g)/(32.06*g*mol^-1` `=` `0.78*mol`.

Clearly the sulfur oxidant is in excess if the copper is incompletely oxidized; `0.66*mol` `Cu_2S` may be formed,

`0.66*molxx159.16*g*mol^-1` `=` `??g`

Look at your stoichiometric equation and divide by 2.

`2Cu + S rarr Cu_2S`

It tells you that approx. `63*g` of copper metal react with approx. `16*g` of sulfur. Why? Because that is the molar mass of each element is `63.55*g` and `32.06*g` respectively. Good luck in your test.