Answer:
The mass of copper(II) sulfide formed is:
= 81.24 g
Explanation:
The Balanced chemical equation for this reaction is :

given mass= 54 g
Molar mass of Cu = 63.55 g/mol

Moles of Cu = 0.8497 mol
Given mass = 42 g
Molar mass of S = 32.06 g/mol

Moles of S = 1.31 mol
Limiting Reagent :<em> The reagent which is present in less amount and consumed in a reactio</em>n
<u><em>First find the limiting reagent :</em></u>

1 mol of Cu require = 1 mol of S
0.8497 mol of Cu should require = 1 x 0.8497 mol
= 0.8497 mol of S
S present in the reaction Medium = 1.31 mol
S Required = 0.8497 mol
S is present in excess and <u>Cu is limiting reagent</u>
<u>All Cu is consumed in the reaction</u>
Amount Cu will decide the amount of CuS formed

1 mole of Cu gives = 1 mole of Copper sulfide
0.8497 mol of Cu = 1 x 0.8497 mole of Copper sulfide
= 0.8497
Molar mass of CuS = 95.611 g/mol


Mass of CuS = 0.8497 x 95.611
= 81.24 g
Answer:
- Report all accidents, injuries and breakage of class or equipment to instructor immediately.
- Keep pathways clear by placing extra items on the shelves or under the work tables. If under the tables make sure that these items can no be stepped on.
- Long hair (chin-length or longer) must be tied back to avoid catching fire.
- Wear sensible clothing including footwear. Loose clothing should be secure so they do not get caught in a flame or chemicals.
- Work quietly - know what you are doing by reading the assigned experiment before you start to work. Pay close attention to any cautions described in the laboratory exercises.
- Do not taste or smell chemicals.
- Wear safety goggles to protect your eyes when heating substances, dissecting, etc
- Do not attempt to change the position of glass tubing in a stopper.
- Never point a test tube being heated at another student or yourself. Never look into a test tube while you are heating it.
Hope this helps:))
Please mark me as Brainliest.