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figureskater
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Radioactivity of Radon 222!
Uranium is naturally present in rock and soil. At one step in its series of radioactive decays, Uranium produces the chemically inert gas radon-222, with a half-life of 3.82 days. The radon seeps out of the ground to mix into the atmosphere, typically making open air radioactive with activity 0.3 pCi/L. In homes, Rn-222 can be a serious pollutant, accumulating to reach much higher activities in enclosed spaces, sometimes reaching 4.00 pCi/L. If the radon radioactivity exceeds 4.00 pCi/L, the U.S. Environmental Protection Agency suggests taking action to reduce it such as by reducing infiltration of air from the ground.
(a) Convert the activity 4.00 pCi/L to units of becquerels per cubic meter.
148 Bq/m3
(b) How many Rn-222 atoms are in 1 m3 of air displaying this activity?
7.05e7 atoms/m3
(c) What fraction of the mass of the air does the radon constitute?
volume fraction= #of atoms/ # of air molecules
# of air molecules = density of air x volume / average molecular weight of air, this answer then multiplied by avogadro's number (6.0221415e23)
=(0.00122521)(1m^3)/28.96 g/mol *6.0221415e23
=2.55e25
=7.05e7/2.55e25
=2.76e-18
To which I got a comment that my response was within 10% of the correct answer. Not sure if I missed something or did not convert units somewhere..
Please help! its due TONIGHT by midnight thanks!
Homework Statement
Uranium is naturally present in rock and soil. At one step in its series of radioactive decays, Uranium produces the chemically inert gas radon-222, with a half-life of 3.82 days. The radon seeps out of the ground to mix into the atmosphere, typically making open air radioactive with activity 0.3 pCi/L. In homes, Rn-222 can be a serious pollutant, accumulating to reach much higher activities in enclosed spaces, sometimes reaching 4.00 pCi/L. If the radon radioactivity exceeds 4.00 pCi/L, the U.S. Environmental Protection Agency suggests taking action to reduce it such as by reducing infiltration of air from the ground.
(a) Convert the activity 4.00 pCi/L to units of becquerels per cubic meter.
148 Bq/m3
(b) How many Rn-222 atoms are in 1 m3 of air displaying this activity?
7.05e7 atoms/m3
(c) What fraction of the mass of the air does the radon constitute?
Homework Equations
The Attempt at a Solution
volume fraction= #of atoms/ # of air molecules
# of air molecules = density of air x volume / average molecular weight of air, this answer then multiplied by avogadro's number (6.0221415e23)
=(0.00122521)(1m^3)/28.96 g/mol *6.0221415e23
=2.55e25
=7.05e7/2.55e25
=2.76e-18
To which I got a comment that my response was within 10% of the correct answer. Not sure if I missed something or did not convert units somewhere..
Please help! its due TONIGHT by midnight thanks!