When deciding upon which fuel source used to power a vechicle, engineers often use the heat released in combustion of differning fuels to make their decision. Would you use the heat released per mole of a hydrocarbon or the heat released per gram of a hydrocarbon to make a decision. State why from an engineering standpoint.
I understand that the fuel has to be carried in a fixed mass tank by the vehicle but I'm not really sure how to answer this question.
Fricion is dependent on weight of the car. YOu need to reduce weight to reduce friction. Energy per gram is the way to go.
thank you
To determine which fuel source is more suitable for a vehicle, engineers typically consider the heat released in the combustion of different fuels. When comparing the heat released per mole of a hydrocarbon versus the heat released per gram of a hydrocarbon, an engineer would typically use the heat released per mole to make a decision. Here's why:
1. Consistency in Chemical Reactions: The heat released per mole provides a more consistent measure of the amount of energy released during combustion. This is because chemical reactions occur based on the number of moles of reactants, not their mass. By using the heat released per mole, engineers can compare different hydrocarbons on an equal footing, regardless of their molecular weight.
2. Easier Conversion: The heat released per mole allows for easier conversion between different units of measurement. Engineers frequently encounter various systems of measurement, such as metric and imperial, and the heat released per mole can be easily and accurately converted between them. This facilitates effective comparison and analysis of different fuel sources.
3. Efficiency Considerations: From an engineering standpoint, it is important to optimize the efficiency of the vehicle's engine. By selecting a fuel source with a high heat release per mole, engineers can maximize the potential energy extracted from the combustion process. This translates to improved fuel efficiency, better performance, and reduced emissions.
4. Accurate Stoichiometric Calculations: Stoichiometric calculations are essential in determining the ideal ratio of fuel to oxygen for efficient combustion. Heat released per mole of a hydrocarbon helps in accurately determining the stoichiometry of the combustion reaction. It allows engineers to calculate the exact amount of fuel required to achieve complete combustion and optimize the air-to-fuel ratio accordingly.
In summary, engineers rely on the heat released per mole when deciding upon the fuel source for a vehicle due to its consistency, ease of conversion, relevance to efficiency considerations, and accuracy in stoichiometric calculations.