Chemistry Unit C1 Topic 1 The Earth’s sea and atmosphere. Everything you need to know for your exam. Part of a 5 part series

1. Edexcel GCSE
Chemistry C1 Topic 1
Higher
Josh Newton

2. Unit 1 - topic 1 - early atmosphere
The early atmosphere was formed by volcanoes.
It contained large amounts of Carbon Dioxide and Water
vapour
Very small amounts of Oxygen and other gases
The Earth was very hot to start off with, and there were no
oceans.
As the Earth cooled, the water vapour in the atmosphere
condensed to form liquid water. This became the
oceans.

3. Questions
Q - Why is it difficult to be precise about the
early atmosphere? (E-C)
Q - Write the balanced equation for the
formation of Iron Oxide Fe(2)O(3). Give the
state symbols (A*-B)

4. Answers
A - Because people weren’t around at the time
to measure it
A - 4Fe (s) + 3O(2) (g) → 2Fe(2)O(3) (s)

5. A changing atmosphere
The atmosphere is shown in the
pie chart
The atmosphere also contains water vapour but this is not included because it
changes depending on the weather
The atmosphere is changed by human activities such as:
● Burning fossil fuels releases Carbon dioxide into the atmosphere. Burning coal
also releases Sulfur dioxide
● Farming as cattle and rice crops release methane
● Deforestation adds carbon dioxide to the atmosphere if the trees are burnt.
There are also fewer trees to photosynthesize and remove carbon dioxide in
the atmosphere
● There are also natural causes such as volcanos emitting carbon dioxide and
sulfur

6. Questions
Q - Explain how the following activities can
change the atmosphere:
● Deforestation
● Generating electricity using fossil fuels

7. Answers
A - 1. Less trees to photosynthesize so less
carbon dioxide is removed
2. Burning fossil fuels emits carbon dioxide -
and if it is coal then sulfur dioxide.