Question

Copper(II) sulfide is formed when copper and sulfur are heated together. In this reaction,

54 g of copper reacts with 42 g of sulfur. What is the mass of copper(II) sulfide formed?

Answer 1

The mass of copper(II) sulfide formed is:

= 81.24 g

Step-by-step explanation:

The Balanced chemical equation for this reaction is :

`Cu(s) + S\rightarrow CuS`

given mass= 54 g

Molar mass of Cu = 63.55 g/mol

`Moles = (given\ mass)/(Molar\ mass)`

`moles=(54)/(63.55)`

Moles of Cu = 0.8497 mol

Given mass = 42 g

Molar mass of S = 32.06 g/mol

`Moles = (given\ mass)/(Molar\ mass)`

`moles=(42)/(32.06)`

Moles of S = 1.31 mol

Limiting Reagent : The reagent which is present in less amount and consumed in a reaction

First find the limiting reagent :

`Cu + S\rightarrow CuS`

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 Cu is limiting reagent

All Cu is consumed in the reaction

Amount Cu will decide the amount of CuS formed

`Cu + S\rightarrow CuS`

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

`Moles = (given\ mass)/(Molar\ mass)`

`0.8497 = (given\ mass)/(95.611)`

Mass of CuS = 0.8497 x 95.611

= 81.24 g