S3 - Chemistry Test (4) Flashcards
What is a fuel?
A compound which has stored energy
How do fuels release their stored energy?
By reacting with oxygen
What is a fuel reacting with oxygen referred to as?
Combustion / Oxidation
What are three different types of fuels?
- Petrol
- Diesel
- Glucose
- Charcoal
- Wax
- Wood
- Hydrogen
What is complete combustion?
When a fuel burns on a plentiful supply of oxygen
What are the products of complete combustion?
Water & Carbon dioxide
What is the equation for complete combustion?
Fuel + Oxygen ~> Water + Carbon dioxide
What are the three things required in order for a fire start?
Fuel, Oxygen & Heat
What is incomplete combustion?
When a fuel burns in a limited supply of oxygen.
What are the products of incomplete combustion?
Carbon monoxide, Soot, Water
What is the equation for incomplete combustion?
Fuel + Insufficient oxygen ~> Carbon monoxide + Soot + Water
What is crude oil?
A mixture of different hydrocarbons with different melting & boiling points
What is fractional distillation?
When hydrocarbon compounds are separated into different groups (fractions) due to them having different boiling points
What is a fraction?
A group of hydrocarbons with similar boiling points
What are hydrocarbons?
Substances made up of only Hydrogen and Carbon
Why do larger hydrocarbons have higher boiling points?
Because more energy is needed to break them down
Why are smaller hydrocarbons more flammable?
Because they evaporate easily and then mix with oxygen
Why do larger Hydrocarbons have a higher viscosity?
Because the molecules get tangled together
What is the general formula for alkanes?
CnH2n+2
What is the general formula for alkenes?
CnH2n
What is the general formula for cycloalkanes?
CnH2n
What are the prefixes used when talking about hydrocarbons and what numbers are they equal to?
Meth - 1
Eth - 2
Prop - 3
But - 4
Pent - 5
Hex - 6
Hept- 7
Oct - 8