Question

Calculate the number of moles of chlorine needed to form 14 moles of iron (III) chloride. 2Fe + 3Cl2 --> 2FeCl3.
Responses

7 mol
7 mol

3 mol
3 mol

21 mol
21 mol

42 mol

Answer 1

To determine the number of moles of chlorine needed to form 14 moles of iron (III) chloride (FeCl₃), we can use the stoichiometry of the balanced chemical equation:

\[ 2 \text{Fe} + 3 \text{Cl}_2 \rightarrow 2 \text{FeCl}_3 \]

From the balanced equation, we see that:

- 2 moles of FeCl₃ are produced from 3 moles of Cl₂.

To find out how many moles of Cl₂ are needed to produce 14 moles of FeCl₃, we set up a proportion based on the coefficients in the reaction:

\[
\text{If } 2 \text{ moles of FeCl}_3 \text{ need } 3 \text{ moles of Cl}_2, \text{ then } 14 \text{ moles of FeCl}_3 \text{ need } x \text{ moles of Cl}_2.
\]

Using the ratio:

\[
\frac{3 \text{ moles of Cl}_2}{2 \text{ moles of FeCl}_3} = \frac{x \text{ moles of Cl}_2}{14 \text{ moles of FeCl}_3}
\]

Cross-multiplying gives:

\[
3 \times 14 = 2 \times x
\]

This simplifies to:

\[
42 = 2x
\]

Now, divide both sides by 2:

\[
x = \frac{42}{2} = 21
\]

Thus, **21 moles of chlorine (Cl₂)** are needed to form 14 moles of iron (III) chloride (FeCl₃).

So the correct response is:

**21 mol**