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Correct Answer: B
Correct Answer: B
Method / Topic: General Chemistry
The correct option matches the required rule and the given information.
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Correct Answer: B
Method / Topic: General Chemistry
The tablet consumed 8.00 mmol H+. The balanced reaction requires 2 mol H+ per 1 mol CaCO3, so CaCO3 amount = 8.00/2 = 4.00 mmol = 0.00400 mol. Multiplying by 100 g/mol gives 0.400 g CaCO3. The remaining 0.100 g consists of nonreactive tablet ingredients. This result follows from the balanced chemical relationship and the stated conditions; no unstated biological assumption is needed. On MCAT chemistry problems, first identify the governing principle, write the relevant equation with units, and only then substitute values. Check whether the
prevents dosage, dilution, and preparation errors.
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PASSAGE 1 — ANTACID BACK-TITRATION A laboratory evaluates a 0.500 g antacid tablet whose active ingredient is calcium carbonate, CaCO3. The tablet is treated with 50.0 mL of 0.200 M HCl. Calcium carbonate reacts according to CaCO3(s) + 2H+(aq) → Ca2+(aq) + CO2(g) + H2O(l). After the reaction is complete, the remaining acid requires 20.0 mL of 0.100 M NaOH for neutralization. Assume that other tablet ingredients do not react with either acid or base. QUESTION 2: What mass of CaCO3 was present in the tablet? (Molar mass CaCO3 ≈ 100 g/mol)
Explanation
Correct Answer: B
Method / Topic: General Chemistry
The correct option matches the required rule and the given information.
Short Explanation
Detailed Explanation
Correct Answer: B
Method / Topic: General Chemistry
The tablet consumed 8.00 mmol H+. The balanced reaction requires 2 mol H+ per 1 mol CaCO3, so CaCO3 amount = 8.00/2 = 4.00 mmol = 0.00400 mol. Multiplying by 100 g/mol gives 0.400 g CaCO3. The remaining 0.100 g consists of nonreactive tablet ingredients. This result follows from the balanced chemical relationship and the stated conditions; no unstated biological assumption is needed. On MCAT chemistry problems, first identify the governing principle, write the relevant equation with units, and only then substitute values. Check whether the
prevents dosage, dilution, and preparation errors.
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