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Unformatted text preview: Version 446 – Quiz 1 – Laude – (52390) 1 This print-out should have 8 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 5.0 points A salt that dissolves in water has an endother- mic heat of solution. Which of the following numerical values might correctly describe the salt’s lattice energy, heat of hydration and the heat of solution, for dissolving in water, respectively? 1.-800 kJ/mole, 805 kJ/mole, 5 kJ/mol 2. 800 kJ/mol, 805 kJ/mol, 1605 kJ/mol 3. 800 kJ/mole, -795 kJ/mole, 5 kJ/mol correct 4.-800 kJ/mole, -805 kJ/mole, -1605 kJ/mol 5. 800 kJ/mole, -795 kJ/mole, -5 kJ/mo Explanation: 002 5.0 points Ice is heated at a constant pressure until it melts and subsequently heated further until it vaporizes. What signs are associated with the total change in entropy and enthalpy (ΔS and ΔH) for this sample of water? 1. ΔS is - and ΔH is + 2. ΔS is + and ΔH is - 3. ΔS is - and ΔH is - 4. ΔS is + and ΔH is + correct Explanation: Two phase transitions occur: melting (the reverse of fusion) and then vaporization. Both phase transitions have a positive ΔS, meaning the water molecules are becoming more dis- ordered as they go from solid, to liquid, then...
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- Spring '09
- Thermodynamics, CH3 OH, – Laude, CH3 CH2 OH