Ozone reacts with dry iodine to form an oxide having ____oxygen atoms in its molecules.

Explanation

To solve the question regarding the reaction of ozone with dry iodine, we will follow these steps:

### Step 1: Identify the reactants
The reactants in this reaction are ozone (O₃) and dry iodine (I₂).

**Hint:** Ozone is a triatomic molecule composed of three oxygen atoms.

### Step 2: Write the reaction
When ozone reacts with dry iodine, it produces an oxide of iodine and oxygen gas. The reaction can be represented as follows:

\[ 3O_3 + 6I_2 \rightarrow I_4O_9 + 3O_2 \]

**Hint:** Remember that ozone acts as a strong oxidizing agent in this reaction.

### Step 3: Determine the product
The product formed from this reaction is tetraiodine nonoxide, which has the chemical formula I₄O₉.

**Hint:** The name of the product can help you identify the number of oxygen atoms in its formula.

### Step 4: Count the oxygen atoms in the product
From the formula I₄O₉, we can see that there are 9 oxygen atoms in each molecule of the product.

**Hint:** Look at the subscript in the chemical formula to find the number of atoms of each element.

### Conclusion
Thus, the oxide formed when ozone reacts with dry iodine contains **9 oxygen atoms** in its molecules.

**Final Answer:** 9