Exam1 chem

Exam1 chem - 1. When 1 mole of white tin changes to gray...

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1. When 1 mole of white tin changes to gray tin at 13.0°C, the change in entropy is —7.5 J@K —1 . This means that __ A. the change from white to gray tin is predicted to be spontaneous on the basis of the entropy change. __ B. white tin is more ordered than gray tin. __ C. gray tin has a higher molar entropy than white tin. __ D. gray tin is more ordered than white tin. __ E. gray tin has an entropy of —7.5 J@K —1 . 2. If H ° = —1202 kJ and S ° = —217 J@K —1 for the combustion of 2 moles of magnesium, the change in entropy of the surroundings at 298 K is __ A. 217 J@K —1 __ B. —217 J K —1 __ C. —4.03 > 10 3 J@K —1 __ D. 5.54 > 10 3 J@K —1 __ E. 4.03 > 10 3 J@K —1 3. Estimate the normal boiling point of ethanol, C 2 H 5 OH, given the molar enthalpy and entropy of vaporization of 38.7 kJ@mol —1 and 110 J@K —1 @mol —1 , respectively. __ A. 11.0°C __ B. 284°C __ C. 78.8°C __ D. 100°C __ E. 352°C 4. For the reaction 2NH 3 (g) ' 3H 2 (g) + N 2 (g) H r ° = 92.22 kJ and S r ° = 198.75 J@K —1 at 298 K. With all reactants and products in their standard states, this reaction will be spontaneous __ A. at all temperatures. __ B. at no temperature. __ C. at temperatures below 463 K. __ D. at temperatures above 464 K. __ E. at 273 K. 1
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5. The equilibrium constant for the reaction NH 4 Cl(s) i NH 3 (g) + HCl(g) is 1.1 > 10 —16 at 25°C. If the equilibrium constant is 6.5 > 10 —2 at 300°C, which statement is correct? __ A. This is an enthalpy-driven reaction. __ B. The reaction is spontaneous at high temperatures. __ C.
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Exam1 chem - 1. When 1 mole of white tin changes to gray...

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