carbon dioxide is a "greenhouse" gas in that it absorbs energy from the sun, causing heating of the atmosphere and eventually global warming. carbon dioxide is produced from the combustion of carbon-containing fuels such as coal (mainly carbon), natural gas (mainly CH4), and petroleum (assume to be C8H18). Given the information in the following table, calculate which fuel contributes the least to global warming by calculating the energy obtained per gram of carbon dioxide produced.
Given
Coal - Carbon = 32kJ/g
Natural gas - CH4 = 49kJ/g
Petroleum - C8H18 = 48kJ/g
I am not sure where to start, with an equation?
or convert 1 g of C to moles and then find the kJ/mol?
I'll give you an example using CH4.
CH4 + 2O2 ==> CO2 + 2H2O
I'm a little confused by the table: I assume it means 49 kJ heat released by 1 g CH4. So we want 1 g CO2; how much CH4 will we need to produce 1 g CO2.
1 g CO2 x (1 mol/44g) = about 0.023 mols. You can go through and clean up the estimates. From the equation, that means we must start with 0.023 mol CH4 and that is 0.023mol x (16g/mol) = 0.36g CH4. That means we must burn 0.36 g CH4 to obtain 1 g C. The energy produced will be 49 kJ/gCH4 x 0.36g CH4 = ??kJ energy.
The others are done the same way but they may not be as simple since the equations may not be 1:1 as CH4 and CO2 are.
i think althought that generally carbon from coal with 32kj/g from natural gas and petroleum very lesser produces energy and global warming.
good luck...
To determine which fuel contributes the least to global warming in terms of energy obtained per gram of carbon dioxide produced, we can calculate the energy obtained per gram of carbon dioxide produced for each fuel.
First, let's establish the equation for the combustion of each fuel:
1. For coal (carbon):
C + O2 → CO2
2. For natural gas (methane):
CH4 + 2O2 → CO2 + 2H2O
3. For petroleum (octane):
C8H18 + (12.5)O2 → 8CO2 + 9H2O
To calculate the energy obtained per gram of carbon dioxide produced, we need to consider the energy released during combustion and the molar mass of carbon dioxide.
For coal (carbon):
- Energy released during combustion of coal: 32 kJ/g
- Molar mass of carbon dioxide (CO2): 44 g/mol
We can convert the given energy per gram of carbon (32 kJ/g) to kJ/mol by using the molar mass of carbon (12 g/mol) and then the molar mass of carbon dioxide:
32 kJ/g * (1 mol/12 g) * (44 g/mol) = 117.33 kJ/mol
Therefore, for coal, the energy obtained per gram of carbon dioxide produced is 117.33 kJ/mol.
Now we can repeat this process for natural gas and petroleum:
For natural gas (CH4):
- Energy released during combustion of natural gas: 49 kJ/g
- Molar mass of carbon dioxide (CO2): 44 g/mol
49 kJ/g * (1 mol/16 g) * (44 g/mol) = 154 kJ/mol
Therefore, for natural gas, the energy obtained per gram of carbon dioxide produced is 154 kJ/mol.
For petroleum (C8H18):
- Energy released during combustion of petroleum: 48 kJ/g
- Molar mass of carbon dioxide (CO2): 44 g/mol
48 kJ/g * (1 mol/114 g) * (44 g/mol) = 17.19 kJ/mol
Therefore, for petroleum, the energy obtained per gram of carbon dioxide produced is 17.19 kJ/mol.
By comparing the values, we find that petroleum (C8H18) contributes the least to global warming in terms of energy obtained per gram of carbon dioxide produced.