. In the production of copper from ore containing copper(II) sulfide, the ore is first roasted to change it to the oxide according to the following equation: 2CuS 3O2 £ 2CuO 2SO2 a. If 100 g of CuS and 56 g of O2 are available, which reactant is limiting? b. What mass of CuO can be formed from the reaction of 18.7 g of CuS and 12.0 g of O2? 4. A reaction such as

Answer :

(a) The limiting reactant is, CuS

(b) The mass of produced is, 15.6 grams.

Explanation :

Part (a) :

Given,

Mass of = 100 g

Mass of = 56 g

Molar mass of = 95.6 g/mol

Molar mass of = 32 g/mol

First we have to calculate the moles of and .

and,

Now we have to calculate the limiting and excess reagent.

The balanced chemical equation is:

From the balanced reaction we conclude that

As, 2 mole of react with 3 mole of

So, 1.05 moles of react with moles of

From this we conclude that, is an excess reagent because the given moles are greater than the required moles and is a limiting reagent and it limits the formation of product.

Hence, the limiting reactant is, CuS

Part (b) :

Given,

Mass of = 18.7 g

Mass of = 12.0 g

Molar mass of = 95.6 g/mol

Molar mass of = 32 g/mol

First we have to calculate the moles of and .

and,

Now we have to calculate the limiting and excess reagent.

The balanced chemical equation is:

From the balanced reaction we conclude that

As, 2 mole of react with 3 mole of

So, 0.196 moles of react with moles of

From this we conclude that, is an excess reagent because the given moles are greater than the required moles and is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of

From the reaction, we conclude that

As, 2 mole of react to give 2 mole of

So, 0.196 mole of react to give 0.196 mole of

Now we have to calculate the mass of

Molar mass of = 79.5 g/mole

Therefore, the mass of produced is, 15.6 grams.

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