The maximum radon level of drinking water was set by EPA at 4.0 pCi/ml water. Ca

Question

The maximum radon level of drinking water was set by EPA at 4.0 pCi/ml water. Calculate the # of Rn-222 atoms (t_1/2=3.8 days) that would there be in 9.0 ml water: {1 pCi=10^12 Ci, 1 Ci=3.70 times 10^10 Bq, 1 Bq=1 decay/s} 7.0 times 10^4 atoms 6.3 times 10^5 atoms 3.5 times 10^6 atoms As the value the of the crystal field splitting. Delta_0. increases from one complex ion to another, _____ the wavelength field absorbed light increases. the number of d electrons increases. the wavelength of absorbed light decreases

Explanation / Answer

decay constant of Rn-222 = 0.693/3.8 days = 0.182 /day = 2.11*10^-6 /sec

amount of decay = 4.0 pCi

                           = 4*10^-12 Ci

                            = 4*10^-12 * 3.7*10^10 decay/sec

                             = 0.148 decay/sec

0.148 decay/sec = number of atoms * decay constant

or, number of atoms = 0.148 decay/sec/decay constant

or, number of atoms of Rn-222 present in 1 mL = 0.148 decay/sec/ 2.11*10^-6 /sec = 7.01*10^4 atoms

Number of atoms present in 9 mL = 9 * 7.01*10^4 atoms = 6.3*10^5 atoms

Correct answer : b

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energy and wavelength are inversely proportional. If spittilg is more, energy absorbed will be more and as a result wavelength of light absorbed will be less.

correct option : c

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