Question

In an experiment, 2.54 grams of copper completely reacts with sulfur, producing 3.18 grams of copper(I) sulfide.

Determine the total mass of sulfur consumed.
Write the chemical formula of the compound produced.

Answer 1

Answer : The total mass of sulfur consumed will be, 0.64 grams and the chemical formula of the compound produced is,
`Cu_2S` copper oxide.

Solution :

According to the law of conservation of mass, the total mass of reactant should be equal to the total mass of product.

The balanced chemical reaction will be,

`2Cu+S\rightarrow Cu_2S`

In this reaction, copper and sulfur are the reactants and copper sulfide is the product.

Let the mass of sulfur be 'x' gram

`\text{The total mass of reactants}=\text{Total mass of copper}+\text{Total mass of sulfur}=2.54g+x`

`\text{The total mass of product}=\text{Total mass of copper sulfide}=3.18g`

According to the law of conservation of mass,

`\text{The total mass of reactants}=\text{The total mass of product}`

`2.54g+x=3.18g`

`x=(3.18-2.54)g`

`x=0.64g`

Therefore, the total mass of sulfur consumed will be, 0.64 grams and the chemical formula of the compound produced is,
`Cu_2S` copper oxide.

Answer 2

0.64 g of S

Solution:

The balance chemical equation is as follow,

2 Cu + S ----> Cu₂S

According to equation,

127 g (2 mole) Cu produces = 159 g (1 mole) of Cu₂S

So,

2.54 g Cu will produce = X g of Cu₂S

Solving for X,

X = (2.54 g * 159 g) / 127 g

X = 3.18 g of Cu₂S

Now, it is confirmed that the reaction is 100% ideal. Therefore,

As,

127 g (2 mole) Cu required = 32 g (1 mole) of S

So,

2.54 g Cu will require = X g of S

Solving for X,

X = (2.54 g * 32 g) / 127 g

X = 0.64 g of S