Chemistry Unit 3 Flashcards
State what a fuel is
Fuels are substances that have stored energy and when burned, release this energy .
Name the three fossil fuels
Crude oil
Coal
Natural gas
Describe how fossil fuels are formed
Formed from animals and plants that where formed in the earth’s crust millions of years ago that contain carbon and hydrogen
Explain what is meant by the term finite with reference to fossil fuels
Finite means that something has only a limited supply, and so you could refer to fossil fuels as finite because they only have very limited supply
Are fossil fuels hydrocarbons?
Yes
However they have only minor impurities
What is crude oil a mixture of and what does it need to do for it to become useful
It is a mixture of hydrocarbons and it needs to be seperated to become useful
Describe the process of fractional distillation
fractional distillation is a process of crude oil being separated into different parts called fractions, in order to become useful
Describe what is meant by a fraction
A fraction is a group of hydrocarbons which have similar boiling points
Name the seven fractions in order from highest to lowest boiling point
(Highest)
-Gas
-gasoline
-naptha
-kerosene
-diesel oil
-lubricating/fuel oil
-residue
(Lowst )
Be able to describe the seven fractions trends in their properties
Lowest: Smallest molecules. Lowest boiling point Lowest viscosity. Lightest in colour.
Highest:Largest molecules. Highest boiling point. Highest viscosity. Darkest in colour.
as you get higher and higher in the fractional coulomb, the bigger you get a bigger, boiling, point, viscosity, molecules etc
State a use for each of the fractions
-Gas: bottled gas
-Gasoline: fuel for vehicles
-naphtha : plastics
-kerosene: fuel for aircrafts
-Diesel oil : fuel for vehicles
-lubricating oil: protects things from rust
-residue : roads
State the products of complete combustion of a hydrocarbon and how to test for them
word equation:
Methane+Oxygen—->Water+Carbon Dioxide
Products: water, Carbon dioxide
Tests:
H2o: cobalt chloride paper turns from blue to pink
Co2: turns limewater cloudy
State the products of incomplete combustion of a hydrocarbon
Word equation:
carbon—–>soot +carbon monoxide
Products:
soot, carbon monoxide
Describe the purpose of catalytic converters in reducing toxic emissions from car exhausts
The catalytic converter is a machine that fits into a car’s exhaust and converts the chemicals thats are bad for the environment (carbon monoxide)into less toxic pollutants. A three
way catalytic converters chemical formula is:
NOx—Nx+Ox
Explain why combustion is described as an exothermic reaction
It is because combustion releases energy when burning fuel in oxygen
Draw the fire triangle and use it to explain how fires are put out
desription: a triangle with the words heat, fuel and oxygen written on each side
there are 3 things a fire triangle needs to burn- these are the 3 sides of the triangle.
In order to extinguash a fire you need to remove one side of the trangle.