Nature's Chemistry: Fuels Flashcards
What does the word ‘fuel’ mean?
A fuel is something that burns to release energy.
What is meant by an ‘exothermic’ reaction?
An exothermic reaction is a reaction within which heat exits.
What is meant by an ‘endothermic’ reaction?
An endothermic reactions is a reaction within which heat enters.
What is meant by ‘combustion’?
Combustion is when a substance reacts with oxygen to create heat and light.
What is the equation that can be used to calculate the heat enthalpy (energy change) in a reaction?
Eₕ = cm△T
When calculating heat enthalpy, what does the symbol ‘m’ stand for, and what unit must it be in?
‘m’ stands for mass, which has to be set in Kilograms (Kg).
When calculating heat enthalpy, what does the symbol ‘△T’ stand for, and what unit must it be in?
‘△T’ stands for change in temperature, and it must be in degrees Celsius (°C)
Would petrol, paraffin, and ethanol all release the same quantity of energy when heating a substance up?
No, Because different fuels release different quantities of energy.
What is meant by the term ‘complete combustion’?
Complete combustion takes place in the presence of a sufficient amount of oxygen. Carbon dioxide and water are produced and energy is given out.
If an alcohol or hydrocarbon is burned completely, what products are formed?
Carbon Dioxide and Water are produced.
What is the test for carbon dioxide?
Limewater. If carbon dioxide is bubbled through limewater, the limewater turns milky or cloudy white.
What is the test for water?
pH paper turns green, as water has a neutral pH of around 7.
Name 2 products that can form due to incomplete combustion.
Carbon Monoxide and Carbon in the form of Soot.
