An Introduction to Thermodynamics phần 5 docx

... ln 7/10/07 2- 54 3. Find ∆S when 2 mol of an ideal gas at 25 C is expanded into vacuum to 10 times its original o volume. 4. A vessel containing 5 mol of an ideal gas, A, is connected to an identical ... ) and of ethane (C H ) at 25 C and 2 4 2 6 o 1 atm are 68.4 and -32.0 kJ/mol. The standard enthalpies of formation are 52 .4 and -84.0 kJ/mol. For the reduction of ethylene...

Ngày tải lên: 08/08/2014, 15:21

... 200 2 O 29.4 25 to 200 2 H O(g)* 36.4 25 to 200 2 SO (g) 41.9 25 to 200 2 S (r) 23.7 25 to 200 S (m) 25. 9 95 to 120 *For rough calculations it is sufficient to set C (steam) = C (ice) = ½ C (liq ... after mixing? There is no energy advantage for the yellow grains to move to the bottom, or back to the top, or to any other specific location. We know that, once mixed, t...

Ngày tải lên: 08/08/2014, 15:21

... important, for example, in the storage of gasoline, which is a mixture of many hydrocarbons. The storage tanks must be vented to the air and consequently water vapor can condense in the tanks. ... constituents, on the temperature, and on the pressure. Therefore the change in free energy arising from changes in any of these quantities can be written as the sum It is to be understood that e...

Ngày tải lên: 08/08/2014, 15:21

... -14.0 0. 25 1.0 2 H O,25g 82.2 66.2 -7.8 0.1 25 1.0 2 Al, 50 g 86. 35 66. 35 -3. 65 0.0 050 0.22 Al, 25g 88.12 68.12 -1.88 0.0276 0.22 * Temperatures in C. ∆T is the temperature change of the sample and o s ∆T ... the change in energy for 2 mol of H warmed at constant volume from 25 C to 2 o 50 C. For a diatomic gas near room temperature, C is constant and is about 5/ 2 R = 21 o 4...

Ngày tải lên: 08/08/2014, 15:21

... system and surroundings and the exact process to be considered. Interchanging “system” and “surroundings” labels may be helpful in analyzing the total process. PHASE CHANGES. Let 5 g of ice melt at ... P dV is a change (in P and V, because P changes with V), so P dV is an inexact differential. W is an amount, not a change in work or any other property, so it is at best misleading to...

Ngày tải lên: 08/08/2014, 15:21

... consisting of constant pressure and constant temperature segments, or constant volume and constant temperature segments. It may be, too, that it will be simpler to return to equation 32. For example, ... w’. IDEAL-GAS EXPANSIONS. The change in free energy of an ideal gas in an isothermal expansion or compression is particularly important because it has been found possible to express...

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... somewhat less spontaneous if the water contains 0 .50 M HCl. The standard free energies of HCl(g) and HCl(aq) are - 95. 27 and - 131.2 kJ/mol, so ∆Go = - 131.2 - (- 95. 27) = - 35. 9 kJ/mol, and (by chosen ... only through ∆S, and therefore subject to an arbitrary additive constant. The change in free energy with temperature is thus also subject to an arbitrary additive constant, an...

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... decomposition of methanol, at this temperature and o constant volume, if the initial pressure of pure methanol is 5 atm. 7. Water and solid sulfur can react to form SO and H S according to the equation 2 ... these ions than CaF . - 2 Inserting these symbols into the equation above gives 7/10/07 4- 104 3. The standard free energies of benzene and cyclohexane are 124 .5 and 28 .5 J/mol...

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... can be totally converted to thermal energy (or “heat”) but thermal energy cannot be totally converted to work (i.e., mechanical energy) in a cyclic process. Thermodynamics provides an understanding ... of statistical mechanics, it is possible to predict which substances are likely to be “apparent exceptions” to the third law and to calculate the exact amount of the discrepancy...

Ngày tải lên: 08/08/2014, 15:21

... m, the tortoise has moved only 10 m. When Achilles has run 10 m, the tortoise has moved 1 m. Each time Achilles runs the distance to where the tortoise had been, the tortoise will have moved to ... geometrically by an area. The second method may be called an antiderivative. Area. In section A.3 we looked at the equation for an ideal gas to find how one quantity changes as another...

Ngày tải lên: 08/08/2014, 15:21