Question

How many moles of CaO are produced when 68.0 g of CaCO3 is heated according to the equation: CaCO3 --> CaO + CO2?
Responses

38 mol
38 mol

68.1 mol
68.1 mol

0.89 mol
0.89 mol

0.68 mol

Answer 1

To determine how many moles of CaO are produced when 68.0 g of CaCO3 is heated, we can use the molar mass of CaCO3 and the stoichiometry of the reaction.

1. **Calculate the molar mass of CaCO3:**
- Calcium (Ca): 40.08 g/mol
- Carbon (C): 12.01 g/mol
- Oxygen (O): 16.00 g/mol (there are 3 oxygen atoms)

\[
\text{Molar mass of CaCO3} = 40.08 \, \text{g/mol} + 12.01 \, \text{g/mol} + (3 \times 16.00 \, \text{g/mol}) = 100.09 \, \text{g/mol}
\]

2. **Convert grams of CaCO3 to moles:**
\[
\text{Moles of CaCO3} = \frac{\text{mass}}{\text{molar mass}} = \frac{68.0 \, \text{g}}{100.09 \, \text{g/mol}} \approx 0.68 \, \text{mol}
\]

3. **Use the stoichiometry of the reaction to find the moles of CaO produced:**
The balanced equation is:
\[
\text{CaCO3} \rightarrow \text{CaO} + \text{CO2}
\]
From the equation, 1 mole of CaCO3 produces 1 mole of CaO. Therefore, the number of moles of CaO produced is also approximately 0.68 mol.

Thus, the correct answer is:

**0.68 mol**