Question

if 5.0g zinc reacts with 10.0 g hci to produce h2 gas and znci2 according to the following equation zn=2hci znci2 + h2 what is the limiting reactant and how many grams of h2 will be produced

Answer 1

Answer: The mass of
`H_2` produced is 0.153 g

Step-by-step explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

`\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}` ......(1)

• For zinc:

Given mass of zinc = 5.0 g

Molar mass of zinc = 65.38 g/mol

Putting values in equation 1, we get:

`\text{Moles of zinc}=(5.0g)/(65.38g/mol)=0.0765mol`

• For HCl:

Given mass of HCl = 10.0 g

Molar mass of HCl = 36.46 g/mol

Putting values in equation 1, we get:

`\text{Moles of HCl}=(10.0g)/(36.46g/mol)=0.274mol`

The given chemical equation follows:

`Zn+2HCl\rightarrow ZnCl_2+H_2`

By stoichiometry of the reaction:

If 1 mole of zinc reacts with 2 moles of HCl

So, 0.0765 moles of zinc will react with =
`(2)/(1)* 0.0765=0.153mol` of HCl

As the given amount of HCl is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.

Thus, zinc is considered a limiting reagent because it limits the formation of the product.

By the stoichiometry of the reaction:

If 1 mole of zinc produces 1 mole of
`H_2`

So, 0.0765 moles of zinc will produce =
`(1)/(1)* 0.0765=0.0765mol` of
`H_2`

We know, molar mass of
`H_2` = 2 g/mol

Putting values in above equation, we get:

`\text{Mass of }H_2=(0.0765mol* 2g/mol)=0.153g`

Hence, the mass of
`H_2` produced is 0.153 g