TA practice exam 3 key


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Unformatted text preview: the following is NOT a state function? 1. E 2. H 3. S 4. q correct 5. G The change of heat by in a process, q, is dependent on the path of the process. For the other properties, it is only necessary to know the current state of the system, for instance E is related only to the temperature. A way to tell if something is a state function is to ask if it is possible to calculate the change in that property by only doing final minus initial. For the other 4 processes, you can do final minus initial to find the change. For q, you also need to know the work done by the process. 5. Which of the following would have a zero enthalpy of formation at 298 K? 1. H 2O(l) 2. H 2O(g) 3. Cgraphite correct 4. Cdiamond 5. none of the above A species only has zero enthalpy of formation if it is in elemental form and its standard state at 298 K. The standard state for carbon is graphite, which means that Cgraphite and an enthalpy of formation of 0 (by definition) at 298 K. 6. Given the following table of heat capacities: Iron: 25 J mol 1K 1 Nickel: 26.07 J mol 1K 1 Copper: 24.440 J mol 1K 1 Rhodium: 24.98 J mol 1K 1 Imagine I take 1 mol of each of these substances at 1000 K and throw each of them into an Olympic size swimming pool. Which pool will have the highest temperature after the pool‐metal system has come to equilibrium? Ignore the effects of the air surrounding the pool cooling the system. 1. Pool + iron 2. Pool + nickel 3. Pool + copper 4. Pool + rodium correct H 2SO4 l ‐813.99 SO2 (aq) 4 H + aq ‐909.27 0 Since the metal is much hotter than the pool, the metal will be transferring heat to the pool. The metal that has the most heat will transfer the most heat to the pool. The metal with the most heat is the metal with the highest heat capacity (since the same amount of metal was used in each case). The metal with the highest heat capacity is nickel. 7. When burned, glucose has a Erxn of 2808 kJ mol 1 . Suppose that 1 mol of pure glucose was burned in a bomb calorimeter containing 1 L of water. If the temperature increases by 50 C after the reaction occurs, what is the hea...
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