Chemistry > GCSE MARK SCHEME > Examiners’ Report June 2018 GCSE Science 1SC0 2CH (All)

Examiners’ Report June 2018 GCSE Science 1SC0 2CH

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Question 1 (a) A question very similar to this has appeared on many papers in the previous specification where they performed well. It was disappointing to see that on this occasion that few student... s appreciated that as a result of the cooling Earth and its atmosphere that the water vapour would condense, fall as rain and form the seas and oceans. Many students surprisingly thought that increasing oxygen or carbon dioxide levels or global temperatures were the cause. Many students also thought that as a result of increasing animal and/or human life caused a greater increase of water usage causing a fall in the amount of water vapour in the atmosphere. Markers ignore any irrelevant writing as long as it does not contradict any of the marking points, which applied to most of this answer. Many students thought that the decrease in amount of water vapour had something to do with carbon dioxide or the greenhouse effect. There was nothing that could be credited for the first mark, but the second mark was given for 'oceans formed'. 1 mark 4 GCSE Science 1SC0 2CHCooling of the Earth or its atmosphere was not mentioned so the first mark was not given. However 'water vapour turned into seas' was given the second mark. 1 mark overall. GCSE Science 1SC0 2CH 5Question 1 (b) (i) Although the calculation was quite straightforward taking the difference in volume and converting that into a percentage, many students simply took the 40 dividing by 50 and converting that into a percentage giving the value of 80% and failed to relate that back to the first line where it stated that the apparatus was used to find the percentage of oxygen in dry air. It was thus surprising to see that they were happy to accept that as the value. However, about half the students carried out a correct calculation to obtain a value of 20%. Some carried out the correct (to give 20%) and the incorrect (to give 80%) calculations but did not then commit themselves. For that the [Show More]

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