Question

How many moles of Cl2 are needed in order to produce 100.0 grams of FeCl3 given the following

equation: 2 Fe + 3 Cl2 → 2 FeCl3
B
T

Answer 1

0.92moles

Step-by-step explanation:

Given reaction:

2Fe + 3Cl₂ → 2FeCl₃

Mass of FeCl₃ = 100g

Unknown:

Number of moles of Cl₂ needed = ?

Solution:

To solve this problem, we work from the known specie to the unknown.

From the mass of the FeCl₃ given, we can solve for the number of moles of the unknown.

• Number of moles of FeCl₃;

Number of moles =
`(mass)/(molar mass)`

Molar mass of FeCl₃ = 56 + 3(35.5) = 162.5g/mol

Number of moles =
`(100)/(162.5)` = 0.62mole

From the reaction expression;

2 mole of FeCl₃ is produced from 3 moles of Cl₂

0.62 mole of FeCl₃ will be produced from
`(0.62 x 3)/(2)` = 0.92mole

The number of moles of Cl₂ = 0.92moles