Fuels Flashcards
Signs which indicate a chemical change
Change in pH, light or heat being given off, gas given off/bubbling, changes in colour, new solid formed
Signs of physical change
Changes of state or size
What is in the fire triangle?
Fuel, heat, oxygen
Why do fire extinguishers vary?
Fire extinguishers vary because usually a water one is used, but if a laptop would be on fire or oil, water would not be used but a fire extinguisher that removes the oxygen.
Why does burning remove some oxygen?
Because oxygen is used up in burning as it is in the fire triangle.
Endothermic vs Exothermic
Endothermic reactions take in heat but exothermic reactions give off heat.
Name a type of Exothermic reaction
Combustion
Why do fuels release energy?
The stored energy inside the fuel is released.
Why do substances often release carbon dioxide and water?
Because most fuels contain carbon hydrogen which releases water and carbon dioxide.
Test for water
Pure copper sulfate is white. It is also known as anhydrous copper sulfate because it has no water in it. When water is present in a sample of copper sulfate it turns blue.
Chemical symbols for carbon dioxide and water
H20 and C02
What are the results of incomplete combustion
During incomplete combustion part of the carbon is not completely oxidized producing soot or carbon monoxide.
Why does incomplete combustion happen?
It happens because Incomplete combustion is generally due to poor mixing of the air and fuel (main one ), insufficient residence time, insufficient temperature and low total excess air.
Reliability vs accuracy
Reliability is about the consistency of a measure, and validity is about the accuracy of a measure
Precision vs accuracy
the more accurate you are, the closer to the true value you are. The more precise you are, the values are closer together.
