Loading…
Loading…
GCSE Chemistry · key term
The layer of gases surrounding a planet.
Used by AQA, Edexcel and OCR
Specification 4.9.1.1, 4.9.1.3 · Paper 2
Revise: Current Atmospheric CompositionEarth’s atmosphere is the layer of gases surrounding the planet. Air is a mixture: it contains different gases together rather than one pure substance. Its composition describes which gases are present and how much of each there is.
The mixture of gases surrounding the Earth.
Specification 4.16, 8.18, 8.22, 8.26 · Paper 1, Paper 2
A unit of pressure based on normal atmospheric pressure; the Haber process operates at about 200 atmospheres.
Revise: Haber Process ConditionsThe numbers must be paired with the correct quantities and units: 450 is the temperature in degrees Celsius, while 200 is the pressure in atmospheres.
The mixture of gases surrounding the Earth.
The layer of gases surrounding Earth.
Specification C6.3a · Paper 2 (Foundation), Paper 4 (Higher)
Revise: Atmospheric FormationThe Earth formed about 4.6 billion years ago. Its early surface was very hot and volcanic activity released gases from inside the planet. These gases are thought to have built up an early atmosphere.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
Revise: Formation of the atmosphereEarth formed about 4.6 billion years ago, long before people could measure its atmosphere. Scientists therefore cannot observe the original atmosphere directly. Instead, they construct explanations from evidence that remains and from processes that can still be studied today.
Learn the three conditions together as 450–200–iron: 450 °C, 200 atmospheres and an iron catalyst.
Use the complete causal sequence: volcanic activity released gases, and these gases formed the Earth’s early atmosphere.
Do not say that volcanoes formed the Earth itself; their role here was to release the gases that formed the early atmosphere.
Create a free account to read GCSE Chemistry revision notes for your exam board and track your progress.