Worksheets4X2 Chemistry Revision
Total questions: 5
Worksheet time: 4mins
Arrange the following steps of fractional distillation of liquid air in correct order.
(1) the liquid air is passed into a fractionating column and warmed up slowly.
(2) air is purified to remove dust, carbon dioxide, water vapour and etc.
(3) purified air is compressed and cooled repeatedly to about -200ºC.
What is the principle (原理) of fractional distillation of liquid air ?
Which of the following is / are correct examples of chemical changes ?
(1) burning fossil fuels (化石燃料)
(2) heating iodine solid
(3) passing electricity through an aluminium sheet (鋁紙)
(1) only
(2) only
(1) and (3) only
(2) and (3) only
Which of the following correctly describes the diagram ?
It is an element
It is a compound
It is a mixture of compounds
It is a mixture of element and compound
Which of the following statements is INCORRECT ?
Oxygen has the highest proportion of any gas in the air.
Aluminium is the most abundant metal on earth.
Silicon is the second most abundant element on earth
fractional distillation of liquid air is an example of physical change
