Question 1: Define the term 'early atmosphere' as it relates to Earth's history.

Answer: The atmosphere of Earth in its initial stages, primarily composed of gases released from volcanic activity, before the development of a stable, oxygen-rich environment.

Question 2: Explain why the early atmosphere was rich in carbon dioxide and water vapour but lacked oxygen.

Answer: Because Earth's early volcanic activity released gases like carbon dioxide and water vapour, while oxygen had not yet been produced in significant amounts through photosynthesis by early organisms.

Question 3: What role did volcanic eruptions play in shaping the early atmosphere?

Answer: Volcanic eruptions released gases such as carbon dioxide, sulphur dioxide, and water vapour, which contributed to forming the initial atmosphere.

Question 1: Calculate the volume of carbon dioxide (CO₂) in litres at standard temperature and pressure (STP) if 0.5 mol of CO₂ is present. (Use the molar volume of 22.4 L/mol).

Answer: 11.2 L

Question 2: If early Earth's atmosphere contained 95% carbon dioxide by volume, how many litres of CO₂ are present in a 100 L sample?

Answer: 95 L

Question 1: Describe a simple experiment to demonstrate the release of gases from volcanic rocks that simulates early atmospheric formation. Include safety precautions.

Answer: Crush volcanic rocks and heat them in a test tube over a flame to release gases. Collect gases in a test tube inverted in water. Safety precautions include wearing goggles and gloves, working in a well-ventilated area, and handling hot equipment carefully.

Question 1: In a simulation, scientists observed that after 1 billion years, oxygen levels increased significantly due to photosynthetic bacteria. Describe the impact this change would have on the composition of the atmosphere and the implications for life on Earth.

Answer: The increase in oxygen would lead to the development of a more oxygen-rich atmosphere, enabling the evolution of complex aerobic organisms and gradually replacing reducing gases like methane and ammonia, making Earth more hospitable for diverse life forms.

Question 1: Explain the process by which Earth's early atmosphere transitioned from being primarily composed of volcanic gases to an oxygen-rich environment. Include key scientific mechanisms involved.

Answer: The transition involved photosynthetic organisms producing oxygen through photosynthesis, which gradually accumulated in the atmosphere. This process converted reducing gases like methane and ammonia into more stable compounds, leading to a rise in oxygen levels. The Great Oxidation Event marked this significant change, enabling aerobic life to thrive.

Question 1: Discuss how knowledge of Earth's early atmosphere can influence current climate change research and atmospheric engineering projects.

Answer: Understanding Earth's early atmosphere helps scientists model how atmospheric composition influences climate, aiding in predicting future climate change. It also guides atmospheric engineering efforts, such as carbon capture and geoengineering, to mitigate human impacts on global climate.