Example Problem with Complete Solution

2A-2 : Automobile Fuel 2 pts
Automobile fuel, known as gasoline or petrol, is a mixture of many types of hydrocarbon molecules. Is the fuel a heterogeneous or homogeneous mixture?
Are there any conditions under which this fuel can be considered to be a pure substance? Explain.
If the fuel is well-mixed, then the mixture can be adequately described as homogeneous. The different types of hydrocarbon molecules in gasoline are miscible, so the fuel tends toward uniform composition because the molecules mix by a random, wandering motion called diffusion.
As long as the composition remains constant and uniform throughout, a homogeneous mixture can be treated as a pure substance.  We call this a pseudo-component.