Introduction
To determine the mass of hydrochloric acid (HCl) needed to decompose 50g of limestone (calcium carbonate, CaCO3), we need to understand the chemical reaction involved.
Chemical Reaction
- The decomposition of limestone can be represented by the equation:
CaCO3 + 2 HCl → CaCl2 + CO2 + H2O
- In this reaction, 1 mole of calcium carbonate reacts with 2 moles of hydrochloric acid.
Molar Mass Calculation
- Molar mass of CaCO3:
- Calcium (Ca): 40.08 g/mol
- Carbon (C): 12.01 g/mol
- Oxygen (O): 16.00 g/mol × 3 = 48.00 g/mol
- Total = 40.08 + 12.01 + 48.00 = 100.09 g/mol
- Molar mass of HCl:
- Hydrogen (H): 1.01 g/mol
- Chlorine (Cl): 35.45 g/mol
- Total = 1.01 + 35.45 = 36.46 g/mol
Moles of Limestone
- To find the moles of 50g of CaCO3:
- Moles of CaCO3 = mass / molar mass = 50 g / 100.09 g/mol ≈ 0.499 moles
Calculating HCl Required
- Since 1 mole of CaCO3 requires 2 moles of HCl:
- Moles of HCl needed = 2 × 0.499 moles = 0.998 moles
Mass of HCl
- To find the mass of HCl:
- Mass = moles × molar mass = 0.998 moles × 36.46 g/mol ≈ 36.41 g
Conclusion
To decompose 50g of limestone, approximately 36.41g of hydrochloric acid is required.