Question | Answer |
What are the products of incomplete combustion? | Soot (carbon) and carbon monoxide |
What are the combustion reactions assumed to be? | Complete |
How high in energy output are carbon based fuels? | High. They release large amounts of energy when burnt. |
What is a disadvantage of carbon-based fuels? | They release harmful gases to the atmosphere. |
What are carbon-based fuels also used for? | Feedstock for the chemical industry. |
What are fuels usually measured on? | A per gram or litre basis. |
How do you convert kJ/g to kJ/L | Multiply by density (g/L) |
What is a bomb calorimeter used for? | To accurately determine the ΔH for a combustion reaction. |
What is a bomb calorimeter made of? | An enclosed steel container - to prevent evaporation of the fuel. |
How does a bomb calorimeter work? | The fuel is ignited and the heat released heats up the surrounding water.
The ΔT is used, along with the change in mass of the fuel (that tells us the number of moles were burnt) to calculate the ΔH. |
What are some systematic errors that occur in combustion reactions that result than lower than expected enthalpy values? | 1) Some energy is lost heating the surroundings (air or calorimeter)
2) Some incomplete combustion occurs
3) The combustion reaction was not carried out under constant pressure
4) The combustion did not take place immediately.
5) Some fuel evaporated. |