The Earth is almost spherical and is surrounded by an atmosphere - AQA - GCSE Chemistry - Question 6 - 2014 - Paper 1
Question 6
The Earth is almost spherical and is surrounded by an atmosphere.
Figure 5 shows a section of the layered structure of the Earth.
6 (a) In 1915 Alfred Wegener put ... show full transcript
Worked Solution & Example Answer:The Earth is almost spherical and is surrounded by an atmosphere - AQA - GCSE Chemistry - Question 6 - 2014 - Paper 1
Step 1
6 (a) (i) Why did most scientists in 1915 not accept Wegener’s idea of continental drift?
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Answer
Most scientists in 1915 did not accept Wegener's idea of continental drift because he could not provide sufficient evidence or a mechanism that explained how continents could move. His theory lacked the scientific backing necessary to be widely accepted at the time.
Step 2
6 (a) (ii) Describe how and explain why continental drift takes place.
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Continental drift occurs due to the movement of tectonic plates that make up the Earth's crust. These plates float on the semi-fluid asthenosphere beneath them and are driven by convection currents caused by the heat from radioactive processes occurring in the Earth's interior. The heat causes the mantle to circulate, leading to the movement of the tectonic plates, which results in the drifting of continents. In the context of Figure 5, X would correspond to the crust (which includes tectonic plates), and Y would refer to the mantle beneath it.
Step 3
6 (b) (i) Suggest one reason why carbon dioxide is removed before the gases are cooled to -200 °C.
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Carbon dioxide is removed before cooling because it forms a solid or freezes at the temperatures involved; this would block the pipes and hinder the separation process.
Step 4
6 (b) (ii) Draw a ring around one gas that does not condense when the remaining gases are cooled to -200 °C.
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The gas that does not condense is neon.
Step 5
6 (b) (iii) Name the gas and give a reason for your answer.
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Answer
The gas is argon. This is because the boiling points of argon and oxygen are almost the same or differ by only a few degrees, leading to the presence of argon in the oxygen separated during the process.
