The reaction ` 2C + O_(2) rarr 2CO` is carried out by taking 24.0 g of carbon and 96.0 g of `O_(2)`. Find out.
Which reactant is left in excess ?

Answer

To determine which reactant is left in excess in the reaction \( 2C + O_2 \rightarrow 2CO \), we will follow these steps:

### Step 1: Write the balanced chemical equation
The balanced equation for the reaction is:
\[ 2C + O_2 \rightarrow 2CO \]

### Step 2: Calculate the number of moles of each reactant
1. **For Carbon (C)**:
- Given mass of carbon = 24.0 g
- Molar mass of carbon = 12 g/mol
- Number of moles of carbon:
\[ \text{Moles of C} = \frac{\text{mass}}{\text{molar mass}} = \frac{24.0 \, \text{g}}{12 \, \text{g/mol}} = 2 \, \text{moles} \]

2. **For Oxygen (O2)**:
- Given mass of oxygen = 96.0 g
- Molar mass of \( O_2 \) = 32 g/mol (16 g/mol for each oxygen atom)
- Number of moles of oxygen:
\[ \text{Moles of } O_2 = \frac{96.0 \, \text{g}}{32 \, \text{g/mol}} = 3 \, \text{moles} \]

### Step 3: Determine the stoichiometric requirements
From the balanced equation, we see that:
- 2 moles of carbon react with 1 mole of oxygen.

### Step 4: Calculate the required moles of oxygen for the available moles of carbon
- For 2 moles of carbon, the required moles of oxygen:
\[ \text{Required moles of } O_2 = \frac{2 \, \text{moles of C}}{2} = 1 \, \text{mole of } O_2 \]

### Step 5: Compare the available moles of oxygen with the required moles
- Available moles of \( O_2 \) = 3 moles
- Required moles of \( O_2 \) = 1 mole

### Step 6: Identify the excess reactant
Since we have 3 moles of \( O_2 \) available and only 1 mole is required, oxygen is in excess.

### Conclusion
The reactant left in excess is **Oxygen (O2)**.

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