which two substances do geologists use in radiocarbon dating?
Geologists use \(\boxed{{\text{carbon - 12 and carbon - 14}}}\) in radiocarbon dating.
Further Explanation:
Radiocarbon dating is a technique that is used to determine the age of a substance with the help of radioactive carbon isotope. It is also known as carbon dating or carbon-14 dating. This is primarily used in archaeology to determine the age of fossil fuels.
Naturally, carbon exists in two stable nonradioactive forms and these are carbon-12 and carbon-13. It has one unstable radioactive isotope of carbon-14.
Carbon-14 is also known as radiocarbon. It is formed continuously in the lower stratosphere and upper troposphere. When neutrons are made to strike on nitrogen-14 atom, the formation of carbon-14 takes place. The formation reaction of carbon-14 is as follows:
\(_{\text{7}}^{{\text{14}}}{\text{N}} + {\text{n}} \to _{\text{6}}^{{\text{14}}}{\text{C}} + {\text{p}}\)
Here,
\(_{\text{7}}^{{\text{14}}}{\text{N}}\) is an atom of nitrogen-14.
n is a neutron.
p is a proton.
\(_{\text{6}}^{{\text{14}}}{\text{C}}\) is an atom of carbon-14.
The expression to determine the age of any substance is as follows:
\({\text{Age}} = - 8033 \cdot \ln \left( {Fm} \right)\)
Here, Fm is the fraction modern.
The fraction modern (Fm) is defined as the ratio of carbon-14 to that of carbon-12 present in the sample \(\left( {^{{\text{14}}}{\text{C}}{{\text{/}}^{12}}{\text{C}}} \right)\).
Since both carbon-12 and carbon-14 are used in the expression to calculate the age of any substance, both are used in radiocarbon dating.
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Answer details:
Grade: Senior School
Chapter: Nuclear chemistry
Subject: Chemistry
Keywords: radiocarbon dating, carbon dating, carbon-14, age, nitrogen-14, carbon-14 dating, neutron, proton, carbon-12, carbon-13, unstable, stable, radioactive, non-radioactive, radiocarbon, upper troposphere, lower stratosphere, carbon, substance.
