Earth & Atmospheric Science Flashcards
All 21 cards in this deck
What produced the gases that formed the Earth's early atmosphere?
Volcanic activity.
What is the Earth's early atmosphere thought to have contained?
Little or no oxygen, a large amount of carbon dioxide, water vapour, and small amounts of other gases (e.g. nitrogen, methane, ammonia).
How did the oceans form?
The Earth cooled, so water vapour condensed and fell as rain, forming the oceans.
Name two processes that removed carbon dioxide from the early atmosphere.
It dissolved in the oceans as they formed (later locked up in carbonate rocks and fossil fuels), and photosynthesis by primitive plants.
What does it suggest about the early atmosphere that the oldest rocks contain iron sulfide but no iron oxide, while later rocks contain iron oxide?
There was little or no oxygen at first; oxygen later increased, so iron was oxidised.
What is the chemical test for oxygen, and the positive result?
A glowing splint relights in the gas.
True or false? The increase in oxygen in the Earth's atmosphere was caused by volcanoes releasing oxygen.
False. It was caused by photosynthesis by primitive plants (and photosynthetic organisms such as algae/cyanobacteria).
What is the approximate composition of today's atmosphere?
About 80% (78%) nitrogen, about 20% (21%) oxygen, small amounts of argon, carbon dioxide (about 0.04%) and water vapour.
Name three greenhouse gases in the atmosphere.
Carbon dioxide, methane and water vapour.
What is the greenhouse effect?
Gases in the atmosphere absorb heat radiated from the Earth and re-radiate energy back, keeping the Earth warm.
True or false? Greenhouse gases absorb the heat radiated from the Earth's surface.
True. They then re-radiate energy back towards the Earth, keeping it warm.
What are the steps to find the percentage of oxygen in air using copper (or iron wool)?
e.g. 50 cm of dry air is passed over heated copper and 40 cm remains- Pass the air over the metal until no further change: oxygen is used up.
- Find the volume used: cm.
- Percentage .
In the iron wool experiment on the percentage of oxygen in air, why does the water level rise in the tube?
Oxygen in the trapped air reacts with the iron, so the volume of gas decreases.
True or false? Nitrogen is the main greenhouse gas in the atmosphere.
False. Nitrogen is the most abundant gas but it is not a greenhouse gas; carbon dioxide, methane and water vapour are.
Name one human activity that increases atmospheric carbon dioxide and one that increases methane.
Burning fossil fuels increases carbon dioxide; livestock farming (and landfill/rice paddies) increases methane.
What evidence links human activity to climate change?
A correlation between rising fossil fuel consumption, rising atmospheric carbon dioxide concentration and rising global temperature.
True or false? A correlation between carbon dioxide levels and global temperature proves that carbon dioxide causes the temperature rise.
False. Correlation does not prove cause; another factor could be responsible.
Give two uncertainties in the data used to study climate change.
Measurements are taken at only a few locations so may not represent the whole Earth, and historical data are less accurate (estimated from ice cores/tree rings, older instruments).
State two potential effects on the climate of increased carbon dioxide and methane.
Rising global temperature and rising sea levels (from melting ice and thermal expansion); also more extreme weather and changed rainfall patterns.
Give two ways the effects of increased greenhouse gases may be mitigated.
Using renewable energy or alternative fuels instead of fossil fuels, and planting trees or preserving ecosystems to store carbon; also carbon capture and storage.
When evaluating a way of mitigating climate change, what three things should be considered?
Scale (is it big enough to make a difference), risk, and environmental implications.