1. Which statement about the Earth early atmosphere (~3-4 billion years ago) is
ID: 289462 • Letter: 1
Question
1. Which statement about the Earth early atmosphere (~3-4 billion years ago) is most likely to be TRUE?
It contained less carbon dioxide than today’s atmosphere.
It contained more oxygen than today’s atmosphere.
It contained oxygen levels similar to today’s atmosphere.
It contained less oxygen than today’s atmosphere.
It contained less methane than today’s atmosphere.
2.
Which of these statements is correct about what happened ~2.4-2.3 billion years ago?
Decreased burial of organic carbon led to a rise in atmospheric oxygen and oxidation of iron from insoluble Fe3+ to soluble Fe2+
Decreased burial of organic carbon led to a rise in atmospheric oxygen and oxidation of iron from soluble Fe2+ to insoluble Fe3+
Increased burial of organic carbon led to a rise in atmospheric oxygen and oxidation of iron from insoluble Fe3+ to soluble Fe2+
Increased burial of organic carbon led to a rise in atmospheric oxygen and oxidation of iron from soluble Fe2+ to insoluble Fe3+
3.
Plants preferentially take up Carbon-12 during photosynthesis. What would you expect for rocks that form inorganically during times when organic carbon burial rates are high?
The inorganic rocks would contain more 14N.
The inorganic rocks would contain more 12C.
The inorganic rocks would contain more 13C.
4.
How much C-14 do fossil fuels contain?
It depends on whether it is coal or oil/gas
The same as in the atmosphere currently
Almost none
Half of the amount in the atmosphere currently
5.
Which of the following statements is TRUE?
Isotopes are the same element, but differing chemical composition.
Isotopes have the same mass, but differing chemical composition.
Isotopes are differing elements, but with the same mass.
Isotopes are the same element, but with differing masses.
AIt contained less carbon dioxide than today’s atmosphere.
BIt contained more oxygen than today’s atmosphere.
CIt contained oxygen levels similar to today’s atmosphere.
DIt contained less oxygen than today’s atmosphere.
EIt contained less methane than today’s atmosphere.
Explanation / Answer
1.It contained less oxygen than today’s atmosphere.
As the earlyh earth had more of carbon dioxide and less of oxygen
2.Increased burial of organic carbon led to a rise in atmospheric oxygen and oxidation of iron from soluble Fe2+ to insoluble Fe3+
Banded iron formations are evidence of the rise of oxygen levels. Banded iron formations indicate soluble fe getting oxidized to insoluble Fe3+
3. The inorganic rocks would contain more 13C.
4. Almost none
As C-14 is a radioactive isotope with half life of around 5370 years. Hence fossil fuels wont have any c-14.
5.Isotopes are the same element, but with differing masses.
Isotopes are defined as Atoms with same proton number but different mass number.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.