Final answer:
The question involves chemistry concepts specifically relating to the combustion of methane for heating purposes. It includes stoichiometric calculations, energy efficiency, and environmental impact considerations, such as the carbon footprint of using methane versus other fuels like LPG and coal.
Step-by-step explanation:
The question is seeking to understand several elements of natural gas usage in heating, specifically focusing on the combustion of methane. To perform stoichiometric calculations related to methane usage for the heating of a house, one needs to know the enthalpy change associated with the combustion of methane. This is a critical piece of information as it allows for the determination of how much methane needs to be burnt to achieve a certain amount of heat, taking into account the efficiency of the furnace.
From the extracted information, we can see that when methane gas (CH4) combusts in a furnace, it releases heat energy, an exothermic reaction. Specifically, the combustion of 1 mol of methane releases 890.4 kilojoules of energy. This is represented in the equation: CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) + 890.4 kJ. Using this thermochemical equation, one can calculate the amount of methane in moles required to provide the 3500 kWh of heat with an 89% efficient furnace, and then convert moles to mass and volumetric flow rates as necessary.
Additionally, the question touches on the comparison of heating efficiency and carbon footprint when substituting methane with LPG (liquefied petroleum gas), specifically propane, as well as the production of carbon dioxide and water as a result of combustion. Calculations regarding the volume of air needed for combustion and the amount of coal required to produce the equivalent energy through electrical means are also involved. These aspects link the combustion processes to broader topics of environmental impact and energy efficiency.