5.9 describe the trend in boiling point and viscosity of the main fractions

fraction	carbon atoms in molecule	boiling points	viscosity
•refinery gases	I	I	I
•gasoline	I	I	I
•kerosene	I         increases I	I          increases I	I          increases I
•diesel oil	I	I	I
•fuel oil	I	I	I
•bitumen	v	v	v