Answer to Question #173162 in Chemistry for Jeremy

Question

Lesson 14 question number 4.Solutions of iron (III) chloride, FeCl₃, are used in photoengraving and to make ink. This compound can be made by the following reaction: 2Fe + 3Cl2 = 2FeCl3

a. How many grams of Fe are needed to combine with 4.5 moles of Cl₂?

b. If 240 g of Fe is to be used in this reaction, with adequate Cl₂, how many moles of FeCl₃ will be produced?

5.Ammonia is produced synthetically by the reaction below. How many moles of NH₃ are formed when 200.0 g of N₂reacts with hydrogen?

N2 + 3H2 = 2NH3

6.Iron metal is produced in a blast furnace by the reaction of iron (III) oxide and coke (pure carbon). If 25.0 moles of pure Fe₂O₃ is used, how many grams of iron can be produced? The balanced chemical equation for the reaction is: Fe2O3 + 3C = 2Fe + 3CO

Answer 1

Solution:

(Q4a):

The balanced chemical equation:

2Fe + 3Cl₂ → 2FeCl₃

According to the equation: n(Fe)/2 = n(Cl₂)/3

n(Fe) = 2 × n(Cl₂) / 3 = (2 × 4.5 mol) / 3 = 3.0 mol

Mass of Fe = Moles of Fe × Molar mass of Fe

The molar mass of Fe is 55.845 g mol^-1.

Hence,

Mass of Fe = 3.0 mol × 55.845 g mol^-1 = 167.535 g = 167.5 g

Mass of Fe = 167.5 g

OR (short form solution):

(4.5 mol Cl₂) × (2 mol Fe / 3 mol Cl₂) × (55.845 g Fe / 1 mol Fe) = 167.5 g Fe

(Q4b):

The balanced chemical equation:

2Fe + 3Cl₂ → 2FeCl₃

According to the equation: n(Fe) = n(FeCl₃)

Moles of Fe = Mass of Fe / Molar mass of Fe

The molar mass of Fe is 55.845 g mol^-1.

Hence,

Moles of Fe = 240 g / 55.845 g mol^-1 = 4.2976 mol

n(FeCl₃) = n(Fe) = 4.2976 mol = 4.3 mol

Moles of FeCl₃ = 4.3 mol

OR (short form solution):

(240 g Fe) × (1 mol Fe / 55.845 g Fe) × (2 mol FeCl₃ / 2 mol Fe) = 4.3 mol FeCl₃

(Q5):

The balanced chemical equation:

N₂ + 3H₂ → 2NH₃

According to the equation: n(N₂) = n(NH₃)/2

Moles of N₂ = Mass of N₂ / Molar mass of N₂

The molar mass of N₂ is 28.013 g mol^-1.

Hence,

Moles of N₂ = 200.0 g / 28.013 g mol^-1 = 7.1395 mol

n(NH₃) = 2 × n(N₂) = 2 × 7.1395 mol = 14.279 mol = 14.28 mol

Moles of NH₃ = 14.28 mol

OR (short form solution):

(200.0 g N₂) × (1 mol N₂ / 28.013 g N₂) × (2 mol NH₃ / 1 mol N₂) = 14.28 mol NH₃

(Q6):

The balanced chemical equation:

Fe₂O₃ + 3C → 2Fe + 3CO

According to the equation: n(Fe₂O₃) = n(Fe)/2

n(Fe) = 2 × n(Fe₂O₃) = 2 × 25.0 mol = 50.0 mol

Mass of Fe = Moles of Fe × Molar mass of Fe

The molar mass of Fe is 55.845 g mol^-1.

Hence,

Mass of Fe = 50.0 mol × 55.845 g mol^-1 = 2792.25 g

Mass of Fe = 2792.25 g

OR (short form solution):

(25.0 mol Fe2O3) × (2 mol Fe / 1 mol Fe2O3) × (55.845 g Fe / 1 mol Fe) = 2792.25 g Fe

Answers:

(Q4a): 167.5 g Fe

(Q4b): 4.3 mol FeCl₃

(Q5): 14.28 mol NH₃

(Q6): 2792.25 g Fe