Consider the combustion of one mole of methane gas:
CH4(gas) + 2O2(gas) → CO2(gas) + 2H2O(gas).
The system is at standard temperature (298 K) and pressure (105 Pa) both before and after the reaction.
(a) First imagine the process of converting a mole of methane into its elemental consituents (graphite and hydrogen gas). Use the data at the back of this book to find ΔH for this process.
(b) Now imagine forming a mole of CO2 and two moles of water vapor from their elemental constituents. Determine ΔH for this process.
(c) What is ΔH for the actual reaction in which methane and oxygen form carbon dioxide and water vapor directly? Explain.
(d) How much heat is given off during this reaction, assuming that no “other” forms of work are done?
(e) What is the change in the system’s energy during this reaction? How would your answer differ if the H2O ended up as liquid water instead of vapor?
(f) The sun has a mass of 2 × 1030 kg and gives off energy at a rate of. 3.9 × 1026 watts. If the source of the sun’s energy were ordinary combustion of a chemical fuel such as methane, about how long could it last?
CEM 141 Lecture 36: Temperature part 2 Dr. Jian Hu th November 30 , 2016 Temperature At the same temperature, if the molar mass of the gas increases, what happens to the average velocity it decreases We don’t smell something as quickly because molecules collide with each other and don’t move in a...