Calculate the work (kJ) done during a reaction in which the internal volume expands from 28 L to 59 L againts an outside pressure of 4.6 atm. (1 L-atm=101 J) a.40kj b.0 kj c.-40kj d.-14kj e.14kj

9.53 Using these reactions, find the standard enthalpy change for the formation of 1 mol of PhO(s) from lead metal and oxygen gas. PbO(s)+C(graphite)Pb(s)+CO(g) H = 106.8 kJ 2C(graphite)+O2(g)2CO(g) H= -221.0 kJ If 250 g of lead reacts with oxygen to form lead(II) oxide, what quantity of thermal energy (in kJ) is ahsorhed or evolved?

Coal is used as a fuel in some electric-generating plants. Coal is a complex material, but for simplicity we may consider it to be a form of carbon. The energy that can be derived from a fuel is sometimes compared with the enthalpy of the combustion reaction: C(s)+O2(g)CO2(g) Calculate the standard enthalpy change for this reaction at 25C. Actually, only a fraction of the heat from this reaction is available to produce electric energy. In electric generating plants, this reaction is used to generate heat for a steam engine, which turns the generator. Basically the steam engine is a type of heat engine in which steam enters the engine at high temperature (Th), work is done, and the steam then exits at a lower temperature (Tl). The maximum fraction, f, of heat available to produce useful energy depends on the difference between these temperatures (expressed in kelvins), f = (Th Tl)/Th. What is the maximum heat energy available for useful work from the combustion of 1.00 mol of C(s) to CO2(g)? (Assume the value of H calculated at 25C for the heat obtained in the generator.) It is possible to consider more efficient ways to obtain useful energy from a fuel. For example, methane can be burned in a fuel cell to generate electricity directly. The maximum useful energy obtained in these cases is the maximum work, which equals the free-energy change. Calculate the standard free-energy change for the combustion of 1.00 mol of C(s) to CO2(g). Compare this value with the maximum obtained with the heat engine described here.

The reaction SO3(g)+H2O(l)H2SO4(aq) is the last step in the commercial production of sulfuric acid. The enthalpy change for this reaction is 227 kJ. In designing a sulfuric acid plant, is it necessary to provide for heating or cooling of the reaction mixture? Explain.

Given 2Al2O3(s)4Al(s)+3O2(g)H=3351.4kJ (a) What is the heat of formation of aluminum oxide? (b) What is H for the formation of 12.50 g of aluminum oxide?

9.20 State the first law of thermodynamics briefly in your own words.

Given 2Cr2O3(s)4Cr(s)+3O2(g)H=+2269.4kJ (a) What is the heat of formation of chromium(III) oxide? (b) What is H for the formation of 13.65 g of chromium (III) oxide?

Explain in your own words what is meant by the term entropy. Explain how both matter spread and energy spread are related to the concept of entropy.

For the reaction SF4(g)+F2(g)SF6(g) the value of G is 374 kJ. Use this value and data from Appendix 4 to calculate the value of Gf for SF4(g).

The enthalpy change for the reaction CH4(g)+2O2(g)CO2(g)+2H2O(l) is 891 kJ for the reaction as written. a. What quantity of heat is released for each mole of water formed? b. What quantity of heat is released for each mole of oxygen reacted?