Write the chemical formula of rust.

Options

A. `Fe_(2)O_(3)`
B. `FeO*xH_(2)O`
C. `Fe_(2)O_(3)*xH_(2)O`
D. `Fe_(3)O_(4)*xH_(2)O`

Answer

To determine the chemical formula of rust, we can follow these steps:

### Step 1: Understand what rust is
Rust is commonly known as hydrated ferric oxide. It forms when iron reacts with oxygen and moisture in the environment.

**Hint:** Remember that rust is not just iron oxide but includes water molecules.

### Step 2: Identify the components of rust
Rust primarily consists of iron (Fe) and oxygen (O). The basic oxide formed is ferric oxide, which is represented as Fe2O3.

**Hint:** Ferric oxide indicates that iron is in the +3 oxidation state.

### Step 3: Include water in the formula
Rust is a hydrated form of ferric oxide, meaning it contains water molecules. The general formula for hydrated compounds is written as Fe2O3·xH2O, where x represents the number of water molecules associated with the ferric oxide.

**Hint:** The 'x' in the formula indicates that there can be varying amounts of water in the rust compound.

### Step 4: Write the complete chemical formula
Thus, the complete chemical formula for rust can be expressed as Fe2O3·xH2O, where x can vary depending on the specific conditions under which rust forms.

**Hint:** The presence of water is crucial for the formation of rust, so always include it in the formula.

### Final Answer
The chemical formula of rust is Fe2O3·xH2O.