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This comprehensive report investigates the stoichiometric calculations of carbon dioxide (CO2) emissions from the combustion of petrol (octane) and ethanol. The primary objective is to determine which fuel is more environmentally friendly by examining CO2 emissions, energy content, and flashpoints. Additionally, this study explores the impact of fuel blends on emissions and energy content to shed light on potential alternatives for more sustainable transportation fuels.
The global quest for sustainable and eco-friendly energy sources has intensified in recent years due to growing concerns over climate change and environmental degradation.
One crucial aspect of this endeavor is the evaluation of various fuel options to determine their environmental impact. In this study, we aim to assess the CO2 emissions, energy content, and safety characteristics of two commonly used fuels: petrol (octane) and ethanol.
The investigation involves stoichiometric calculations based on chemical reactions and research data. Our findings will provide valuable insights into which fuel is the better choice in terms of reducing CO2 emissions and enhancing safety.
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Moreover, we will delve into the effects of ethanol blends on energy content and emissions to shed light on potential alternatives for more sustainable transportation fuels.
To determine the amount of CO2 emissions produced when burning 1 liter (L) of octane, we employ stoichiometric calculations. We begin by calculating the number of moles of octane:
1L × 1000mL/1L × 0.702g/1mL × 1mol/114g = 6.16mol
Next, using the balanced chemical equation for the combustion of octane:
2C8H18 + 25O2 → 16CO2 + 18H2O
We calculate the mass (g) of CO2 produced:
| Molar Ratio | Moles (mol) | Mass (g) | Molar Mass (g/mol) | |
|---|---|---|---|---|
| C8H18 | 1 | 6.16 | 696.64 | 114 |
| CO2 | 16 | 6.16 | 1424 | 44 |
The mass of CO2 produced is determined to be 2167.44g or 2.16744 kg/L.
It is essential to convert the mass to kilograms as this unit is more relevant when evaluating emissions.
For every liter of octane burned, approximately 2.17 kg of CO2 is produced.
In the case of ethanol, we investigate the amount of CO2 emissions produced when burning 1.4 liters (L) of ethanol, which is equivalent to the energy content of 1 liter of petrol. We perform stoichiometric calculations as follows:
1.4L × 1000mL/1L × 0.789g/1mL × 1mol/46g = 24.01mol
Next, using the balanced chemical equation for the combustion of ethanol:
C2H5OH + 3O2 → 2CO2 + 3H2O
We calculate the mass (g) of CO2 produced:
| Molar Ratio | Moles (mol) | Mass (g) | Molar Mass (g/mol) | |
|---|---|---|---|---|
| C2H5OH | 1 | 24.01 | 1104.46 | 46 |
| CO2 | 2 | 24.01 | 1056.88 | 44 |
The mass of CO2 produced is determined to be 2112.88g or 2.11288 kg/L.
As with petrol, we convert the mass to kilograms for relevance. For every 1.4 liters of ethanol burned, approximately 2.11 kg of CO2 is produced.
The stoichiometric calculations imply that petrol (octane) produces slightly more CO2 emissions than ethanol when balanced for energy content, indicating a lower environmental impact for ethanol.
Energy output refers to the amount of energy a substance produces during combustion. To assess the energy content of each fuel, we perform enthalpy calculations.
2C8H18 + 25O2 → 16CO2 + 18H2O
ΔH = Bonds Broken - Bonds Formed
ΔH = (36×C-H + 14×C-C + 25×O=O) - (32×C=O + 36×O-H)
= (36×414 + 14×346 + 25×498) - (32×804 + 36×463)
= 32198 - 42396
= -10198 kJ/mol
The energy content of octane is approximately 62.8 kJ/L.
C2H5OH + 3O2 → 2CO2 + 3H2O
ΔH = Bonds Broken - Bonds Formed
ΔH = (5×C-HCOH + 3×O=O) - (4×C=O + 6×O-H)
= (5×414 + 346 + 358 + 463 + 3×498) - (4×804 + 6×463)
= 4731 - 5994
= -1263 kJ/mol
The energy content of ethanol is approximately 21.66 kJ/L.
Comparing the energy content, petrol has a higher energy content than ethanol due to its molecular structure. This higher energy content makes petrol more fuel-efficient.
The flashpoint of a chemical substance is the lowest temperature at which it can produce a combustible concentration of gas. Fuels with higher flashpoints are less flammable and hazardous. Ethanol has a higher flashpoint than petrol, indicating that it is a safer choice in terms of flammability and environmental risk.
The stoichiometric calculations suggest that ethanol produces fewer CO2 emissions compared to petrol when considering an equal energy content. This supports the claim that ethanol is a more environmentally friendly fuel option.
Further examination of the energy content reveals that petrol has a higher energy content than ethanol due to its molecular structure. This characteristic makes petrol more fuel-efficient, allowing vehicles to travel greater distances on less fuel. However, this advantage in fuel efficiency must be weighed against the environmental impact, particularly regarding CO2 emissions.
Commercial petrol often contains ethanol blends such as E10 or E85. These blends alter the composition of the fuel and can impact both energy content and emissions. Further research is needed to assess how different ethanol blends affect these parameters.
The use of ethanol blends has the potential to reduce overall CO2 emissions while maintaining fuel efficiency. It is crucial to investigate these blends to better understand their environmental impact and potential as sustainable fuel alternatives.
In conclusion, this study explored the CO2 emissions, energy content, and safety characteristics of petrol (octane) and ethanol. The findings indicate that ethanol produces fewer CO2 emissions and has a higher flashpoint, making it a more environmentally friendly and safer choice compared to petrol.
While petrol may offer higher fuel efficiency due to its greater energy content, this advantage should be weighed against its higher CO2 emissions. Ethanol, with its lower environmental impact, represents a preferable choice for reducing emissions and mitigating climate change.
It is crucial to acknowledge the limitations of this study:
Further research is needed to explore the impact of different ethanol blends on energy content and emissions. Additionally, the study could delve into other environmental factors such as polarity and emissions from incomplete combustion to provide a more comprehensive assessment of sustainable fuel options.
The findings of this study contribute to the ongoing efforts to identify cleaner and more sustainable energy sources for a greener future.
Stoichiometric Calculations: CO2 Emissions of Petrol and Ethanol. (2024, Jan 18). Retrieved from https://studymoose.com/document/stoichiometric-calculations-co2-emissions-of-petrol-and-ethanol
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