Http://i67.tinypic.com/mrpagn.jpg - Question 27 why is the answer (a)?
回答 (1)
2016-06-10 4:44 pm
27.
The four options are the fractions of petroleum in fractional distillation.
It is known that the bigger the molecules of the fraction, the higher the boiling point range of the fraction is.
The basic principle of fractional distillation of petroleum is to heat the petroleum to 450°C to vaporize the petroleum. The vapor goes up the fractionating tower with decreasing temperature. Different fractions with different boiling point range condense at different levels of the fractionating tower.
Among the four options, bitumen is the highest boiling point fraction which cannot be vaporized at 450°C and is obtained as the residue in vaporization of petroleum, while the other three fractions can be vaporized. Bitumen has the highest boiling point because it contains the biggest molecules and the van der Waals' forces between molecules are the strongest.
...... The answer is : (a) bitumen
The four options are the fractions of petroleum in fractional distillation.
It is known that the bigger the molecules of the fraction, the higher the boiling point range of the fraction is.
The basic principle of fractional distillation of petroleum is to heat the petroleum to 450°C to vaporize the petroleum. The vapor goes up the fractionating tower with decreasing temperature. Different fractions with different boiling point range condense at different levels of the fractionating tower.
Among the four options, bitumen is the highest boiling point fraction which cannot be vaporized at 450°C and is obtained as the residue in vaporization of petroleum, while the other three fractions can be vaporized. Bitumen has the highest boiling point because it contains the biggest molecules and the van der Waals' forces between molecules are the strongest.
...... The answer is : (a) bitumen
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