Soru
resulting solution acidic or bask 4.94 A 1.248 g sample of limestone rock is pulverized and thin treated with 30.00 mL of 1.035 M HCl solution. The exce s acid then requires 11 .56 mL of 1 .010 M NaOH for neutraliz.- tion. Calculate the percentage by mass of calcium carbonate in the rock , assuming that it is the only substance reacting with the HCl solution.
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Cevap
To calculate the percentage by mass of calcium carbonate (CaCO₃) in the limestone rock, we need to follow these steps:1. **Determine the molesCl used:**
[ \text{Moles of HCl} = \text{Volume} \times \text{Concentration} = 0.03000 \, \text{L} \times 1.035 \, \text{M} = 0.03105 \, \text{moles} \]2. **Determine the moles of NaOH used for neutralization:**
3. **Determine the moles of HCl remaining after reacting with CaCO₃:** Since the moles of NaOH used for neutralization are equal to the moles of HCl remaining after reacting with CaCO₃:
4. **Determine the moles of HCl that reacted with CaCO₃:**
5. **Determine the moles of CaCO₃ in the rock:** The reaction between HCl and CaCO₃ is a 1:1 molar ratio:
Therefore, the moles of CaCO₃ are equal to the moles of HCl that reacted:
6. **Determine the mass of CaCO₃ in the rock:**
7. **Determine the percentage by mass of CaCO₃ in the rock:**
Since the percentage by mass cannot be greater than 100%, there might be an error in the calculation or assumptions. Please recheck the steps and data provided.