Question

Copper(II) sulfide, CuS, is used in the development of aniline black dye in textile printing. What is the maximum mass of CuS which can be formed when 38.0 mL of 0.500 M CuCl2 are mixed with 42.0 mL of 0.600 M (NH4)2S? Aqueous ammonium chloride is the other product.

Answer 1

1.82 g is the maximum mass of CuS.

Step-by-step explanation:

Considering:

`Molarity=(Moles\ of\ solute)/(Volume\ of\ the\ solution)`

Or,

`Moles =Molarity * {Volume\ of\ the\ solution}`

Given :

For
`CuCl_2` :

Molarity = 0.500 M

Volume = 38.0 mL

The conversion of mL to L is shown below:

1 mL = 10⁻³ L

Thus, volume = 38.0×10⁻³ L

Thus, moles of
`CuCl_2` :

`Moles=0.500 * {38.0* 10^(-3)}\ moles`

Moles of
`CuCl_2` = 0.019 moles

For
`(NH_4)_2S` :

Molarity = 0.600 M

Volume = 42.0 mL

The conversion of mL to L is shown below:

1 mL = 10⁻³ L

Thus, volume = 42.0×10⁻³ L

Thus, moles of
`(NH_4)_2S` :

`Moles=0.600 * {42.0* 10^(-3)}\ moles`

Moles of
`(NH_4)_2S` = 0.0252 moles

According to the given reaction:

`CuCl_2_((aq))+(NH_4)_2S_((aq))\rightarrow CuS_((s))+2NH_4Cl_((aq))`

1 mole of
`CuCl_2` reacts with 1 mole of
`(NH_4)_2S`

So,

0.019 mole of
`CuCl_2` reacts with 0.019 mole of
`(NH_4)_2S`

Moles of
`(NH_4)_2S` = 0.019 mole

Available moles of
`(NH_4)_2S` = 0.0252 mole

Limiting reagent is the one which is present in small amount. Thus,
`CuCl_2` is limiting reagent.

The formation of the product is governed by the limiting reagent. So,

1 mole of
`CuCl_2` gives 1 mole of
`CuS`

0.019 mole of
`CuCl_2` gives 0.019 mole of
`CuS`

Moles of
`CuS` formed = 0.019 moles

Molar mass of
`CuS` = 95.611 g/mol

Mass of
`CuS` = Moles × Molar mass = 0.019 × 95.611 g = 1.82 g

1.82 g is the maximum mass of CuS.