Question

How many grams of ZnCl2 will be produced from 26.0g of Zn and 42.0g of HCl. Round to three significant figures

Answer 1

Answer: The mass of zinc chloride produced in the reaction is 54.1 grams

Step-by-step explanation:

To calculate the number of moles, we use the equation:

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

• For zinc:

Given mass of zinc = 26 g

Molar mass of zinc = 65.4 g/mol

Putting values in equation 1, we get:

`\text{Moles of zinc}=(26g)/(65.4g/mol)=0.397mol`

• For HCl:

Given mass of HCl = 42 g

Molar mass of HCl = 36.5 g/mol

Putting values in equation 1, we get:

`\text{Moles of HCl}=(42g)/(36.5g/mol)=1.150mol`

The chemical equation for the reaction of zinc and HCl follows:

`Zn+2HCl\rightarrow ZnCl_2+H_2`

By Stoichiometry of the reaction:

1 mole of zinc reacts with 2 moles of HCl

So, 0.397 moles of zinc will react with =
`(2)/(1)* 0.397=0.794mol` of HCl

As, given amount of HCl is more than the required amount. So, it is considered as an excess reagent.

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

By Stoichiometry of the reaction:

1 mole of zinc produces 1 mole of zinc chloride

So, 0.397 moles of zinc will produce =
`(1)/(1)* 0.397=0.397moles` of zinc chloride

Now, calculating the mass of zinc chloride from equation 1, we get:

Molar mass of zinc chloride = 136.3 g/mol

Moles of zinc chloride = 0.397 moles

Putting values in equation 1, we get:

`0.397mol=\frac{\text{Mass of zinc chloride}}{136.3g/mol}\\\\\text{Mass of zinc chloride}=(0.397mol* 136.3g/mol)=54.1g`

Hence, the mass of zinc chloride produced in the reaction is 54.1 grams