Petrol combustion

Petrol combustion

Pencil and paperOnline interactive
Overview
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Connecting to the Curriculum
Marking Student Responses
This task is about complete and incomplete combustion.

Here are two equations describing the burning of petrol.

  1. 2C8H18 + 25O2          16CO2 + 18H2O               10808 kJ energy released
  2. 2C8H18 + 14O2          6C + 10CO + 18 H2O      7624 kJ energy released

Question 2Change answer

a)  Identify each reaction as either complete combustion or incomplete combustion.
     i)   Reaction 1 is  complete combustion.incomplete combustion.
     ii)   Reaction 2 is incomplete combustion.complete combustion.

Question 2Change answer

b)  Describe two disadvantages of incomplete combustion.
1.   2.  
Task administration: 
This task can be completed with pencil and paper or online (with SOME auto marking).
Level:
5
Curriculum info: 
Science, Knowledge, Material World
Keywords: 
energy, combustion, hydrocarbons, fuels, equations
Description of task: 
Students are given two equations describing the burning of petrol. Students identify each as either complete or incomplete combustion and then describe two disadvantages of incomplete combustion.
Curriculum Links: 
 
 
Answers/responses: 
   Y10 (03/1997) Y11 (03/1997)
a) i)
ii)		 Complete combustion.
Incomplete combustion.		 moderate moderate
b) i)

ii)

 Pollution or waste products
formed: soot/carbon (C) and/or
carbon monoxide (CO).
Less energy is released.		 very difficult difficult