Crude oil is separated into fractions in a fractionating column.
Explain how fractional distillation separates crude oil into fractions.
[6 marks]OCR Gateway GCSE Chemistry June 2018 Paper 2
5 questions on this paper's topics
33:001 of 5
Silicon dioxide (silica) melts at 1710 °C. Poly(ethene) softens at about 120 °C. Methane boils at −162 °C.
Explain the differences in these temperatures.
Refer to the structure and bonding of each substance.
[6 marks]A student investigates how the concentration of hydrochloric acid affects the rate of its reaction with magnesium ribbon. Hydrogen gas is produced.
Plan an investigation using a gas collection method.
Include the variables the student should control.
[6 marks]A student wants to make pure, dry crystals of copper sulfate from copper oxide (an insoluble black powder) and dilute sulfuric acid.
Plan a method the student could use.
In your answer, explain the reason for each step.
[6 marks]A student heats 2.40 g of magnesium ribbon in an open crucible. It all reacts to form 4.00 g of magnesium oxide.
.1
Calculate the mass of oxygen that reacted with the magnesium.
[1 mark].2
The student says: "The mass went up, so mass was not conserved."
Explain why the student is wrong.
[2 marks].3
The student repeats the experiment in a sealed container full of air and weighs the whole container. Predict what happens to the total mass.
[1 mark]