By removing long-buried fossil fuels and burning them to produce electricity, human activities have drastically disrupted the natural carbon cycle and released CO2 into the atmosphere. The burning of fossil fuels like coal, natural gas, and oil, including gasoline, is responsible for 85% of all human-produced carbon dioxide emissions.
reductions in atmospheric oxygen concentration and the proportion of other carbon isotopes (14C and 13C) have been observed. Because the natural mechanisms that may restore the balance are too slow relative to the rates at which human activities are adding CO2 to the atmosphere, the extra CO2 from burning fossil fuels and deforestation has upset the equilibrium of the carbon cycle. As a result, a sizeable portion of the CO2 produced by human activity builds up in the atmosphere, where part of it will stay for thousands of years rather than just a few decades or centuries.
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If the reaction is a chemical change, new substances with different properties and identities are formed. This may be indicated by the production of an odor, a change in color or energy, or the formation of a solid.
Energy level and spectral line
Explanation:
The energy levels and their spectral lines are related.
Based on the Bohr's model of the atom, he suggested that electrons occupy specific spherical orbits.
These orbits are called energy levels around the nucleus.
The spectral lines are the different colors emitted by atoms when they absorb or lose energy.
- Electrons can transition between different energy levels when they acquire enough energy that corresponds to that of the energy level
- By doing so, they emit energy in the process and this is seen as visible spectral lines.
- Spectral lines are usually studies in order to gain more information about the properties of atoms.
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i believe the answer is B: both wind up at 60°C
but it's also reasonable to assume, given enough time, they wind up at 20°C because the water would heat up to cool the metal then slowly release the heat to the air untill they both reach 20°C
if it were me I'd answer B, apologies if I'm wrong