AP Chemistryhardmcq1 pt
A calorimeter's water (200 g, c = 4.18 J/g·°C) rises 5.0 °C when 0.010 mol of a substance dissolves. What is ΔH of dissolution per mole?
A.−418 kJ/mol
B.+418 kJ/mol
C.−4.18 kJ/mol
D.−41.8 kJ/mol
Explanation
Core Concept
Water gained 200 × 4.18 × 5.0 = 4180 J. The system (dissolving solute) lost that: −4180 J ÷ 0.010 mol = −418 kJ/mol. Exothermic dissolution.
Correct Answer
A−418 kJ/mol
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