Category: Q&A

cos 2x = sin 230

7918  admin  
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Without using a calculator, find the values of x such that cos 2x = sin 2300, where -1800 ≤ x ≤ 1800 .

Fractional Distillation of Crude Oil

7913  admin  
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(a) Fractional distillation
(b) In the furnace at the bottom of the fractionating tower, petroleum is heated to 400 oC.
The oil vaporizes and enters the fractionating tower at the bottom.
The temperature of the fractionating tower is highest at the bottom and the temperature decreases going up the tower.
As the hot vapour rises up the column, they cool and condense into the trays at various heights depending on their boiling points.
Lighter fractions with the lowest boiling points are distilled over at the top of the fractionating column.
Heavier fractions with the highest boiling points are collected at the bottom of the fractionating column.
(c) Petroleum gas, petrol, naphtha, paraffin, diesel, lubricating oil, bitumen.
(d) (i) Cracking is the breaking of long chain alkanes into shorter chain hydrocarbons.
(d) (ii) There is lower demand for the longer chain alkanes like lubricating oil, and higher demand for shorter chain alkanes like petrol and naphtha. Cracking allows the conversion of the longer chain alkanes into shorter chain alkanes in order to meet the demand for these shorter chain alkanes.