Calculate the number of moles of iodine produced in the decomposition of 7.0 moles of potassium iodide (KI). Express
your answer to the correct number of significant figures.
The number of moles of iodine (1) produced is



Answer :

Sure, let's go through the solution step-by-step:

1. Understand the chemical reaction:
The decomposition of potassium iodide (KI) can be represented by the balanced chemical equation:
[tex]\[ 2 \text{KI} \rightarrow 2 \text{K} + \text{I}_2 \][/tex]
This equation tells us that 2 moles of potassium iodide (KI) decompose to produce 1 mole of iodine (I₂) and 2 moles of potassium (K).

2. Identify the given data and required result:
- We are given 7.0 moles of potassium iodide (KI).
- We need to find out how many moles of iodine (I₂) are produced.

3. Analyze the stoichiometry:
According to the balanced equation, 2 moles of KI produce 1 mole of I₂. Hence, there is a stoichiometric ratio of 2:1 between KI and I₂.

4. Calculate the number of moles of iodine (I₂) produced:
- Since 2 moles of KI yield 1 mole of I₂, we can determine the moles of I₂ by dividing the moles of KI by 2.
[tex]\[ \text{moles of I}_2 = \frac{\text{moles of KI}}{2} \][/tex]
- Substitute the number of moles of KI (7.0 moles) into the equation:
[tex]\[ \text{moles of I}_2 = \frac{7.0 \text{ moles}}{2} \][/tex]
[tex]\[ \text{moles of I}_2 = 3.5 \text{ moles} \][/tex]

5. Express the result with the correct number of significant figures:
- The given value (7.0 moles of KI) has two significant figures.
- Therefore, the calculated number of moles of I₂ should also be expressed with two significant figures.

Thus, the number of moles of iodine (I₂) produced in the decomposition of 7.0 moles of potassium iodide (KI) is [tex]\(3.5\)[/tex] moles.