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Post it. Pollutants are dangerous chemicals in the air are called pollutants. Name as many air pollutants as you can from last lesson. Extension: Circle those which could lead to acid rain. Hydrocarbons and fossil fuels. To develop an understanding of how air pollutants are produced.
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Post it Pollutants are dangerous chemicals in the air are called pollutants. Name as many air pollutants as you can from last lesson. Extension: Circle those which could lead to acid rain
Hydrocarbons and fossil fuels To develop an understanding of how air pollutants are produced
Grade criteria Grade A* - Generate combustion reactions using balance symbol equations. Grade A – Summarise combustion reactions using word equations. Grade B – Explain how atoms are conserved during combustion reactions. Grade C – Identify hydrocarbons and fossil fuels by their molecular pictures Grade D –Define the terms ‘hydrocarbon’ and ‘fossil fuels’, giving examples of each
Combustion, fuels and hydrocarbons When a substance burns, it is said to combust. Combustion is a rapid reaction between a substance and oxygen that releases heat and light energy. A fuel is a substance that reacts with oxygen (combusts) to release useful energy. Many fractions obtained from crude oil are used as fuels because they contain hydrocarbons that burn easily and release a large amount of useful energy.
Hydrocarbons– What’s so good about them? • Contain carbon and hydrogen atoms only • Can have different carbon chain lengths • Length of the chain determines the use • Crude oil is a mixture of lots and lots of different hydrocarbons.
carbon dioxide + + hydrocarbon oxygen water Complete combustion of hydrocarbons Plenty of air is needed to provide enough oxygen for a hydrocarbon fuel to burn completely. The blue flame of a gas hob or a Bunsen burner is an example of complete combustion of a hydrocarbon (in this case, natural gas). What are the products of thecomplete combustion of a hydrocarbon?
carbon dioxide + + hydrocarbon oxygen water Do you think that combustion is as simple as:
VCOP – What are particulates? Consider your observations, which flame would it have been?
Grade criteria Grade A* - Generate combustion reactions using balance symbol equations. Grade A – Summarise combustion reactions using word equations. Grade B – Explain how atoms are conserved during combustion reactions. Grade C – Identify hydrocarbons and fossil fuels by their molecular pictures Grade D –Define the terms ‘hydrocarbon’ and ‘fossil fuels’, giving examples of each
Plenary: Methane bubbles • What is a hydrocarbon? Name an example • Give a general word equation for combustion • Name a product of incomplete combustion? How is it harmful? • Balance the equation
Homework • Complete pages 20 – 23/24/25
For each answer below write as many questions as you can think of
Explain why crude oil is an invaluable resource • Know the origins of crude oil • Describe the process to separate crude oil • Recognise the uses of the fractions of crude oil
Hydrocarbons– What’s so good about them? • Contain carbon and hydrogen atoms only • Can have different carbon chain lengths • Length of the chain determines the use • Crude oil is a mixture of lots and lots of different hydrocarbons.
How crude oil was formed • Microscopic plants and animals die and fall to the sea bed • Layers of sand and mud form on top • Pressure and high temperature cause oil to form • Oil obtained by drilling
Explain why crude oil is an invaluable resource • Know the origins of crude oil • Describe the process to separate crude oil • Recognise the uses of the fractions of crude oil
The Fractional Distillation of Crude Oil Average number of C atoms in chain Fraction Boiling pt. Refinery gas 3 < 25oC 40oC Petrol 25 – 60oC 8 Naptha 60 – 180oC 10 Kerosine 180 – 220oC 12 Diesel oil 20 220 – 250oC Fuel oil 40 250 – 300oC Lubricating oil 80 300 – 350oC Bitumen 120 > 350oC 350oC HeatedCrude Oil
Explain why crude oil is an invaluable resource • Know the origins of crude oil • Describe the process to separate crude oil • Recognise the uses of the fractions of crude oil
The Molymod challenge • Rules Carbon atoms always make 4 bonds • Hydrogen atoms are smaller • Hydrogen atoms can only make one bond Make the molecule methane (1 Carbon to 4 Hydrogens) Make the molecule propane (3 carbons to ? Hydrogens) Make the molecule hexane (? Carbons to 14 Hydrogens)
Complete the table Extension: what is the word equation for combustion?