helpmewithmath70

05.07.2019 • 

Chemistry

Radon gas as rn-222 is formed by the radioactive decay of u-238, the chief natural isotope of uranium, found in soils and especially granitic rocks. as rn-222, radon decays through several daughter-product isotopes to stable pb-2016. the gas occurs in air at natural levels of 0.1 to 0.2 pci/l, and is considered a health hazard (cancer risk) by the u.s. environmental protection agency at or above 4 pci/l in air. rn-222 decays by the emission of alpha particles (helium nuclei) with a half-life or decay half-time of 3.823 days.
(a) what is its decay rate constant in s-1?
(b) the mole fraction solubility of pure radon gas in water (nrn) from 3 to 970c at 1 atm radon gas pressure, is given by the equation
r in nrn = -499.309 + (25864.2/t) + 69.3241 in t + 0.00101227 t
where r = 1.9872 cal/mol k, and t is in degrees k. calculate the henry's law constant for rn gas at 250 c in m/bar?
(c) well waters pumped from granitic rocks or uraniferous sandstones may be high in radon. exsolution of the gas into the air in a shower stall may result in air levels in excess of 4pci/l. what m concentration of dissolved rn in a groundwater would be in equilibrium with 4 pci/l of radon gas in bathroom air at 250c.

Ответ:

CorsoGod

16.10.2022

Chemistry

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Concentration of Solutions is oftenly expressed in Molarity. Molarity is the number of moles of solute dissolved per volume of solution.

                             Molarity  =  Moles / Volume
As,
      Moles  =  Mass / M.mass
So,
                             Molarity  =  Mass / M.mass × Volume    (1)

Data Given;
                   Volume  =  0.750 L

                   Mass  =  52 g

                   M.mass  =  180 g/mol

Putting Values in eq.1,

                     Molarity  =  52 g ÷ (180 g.mol⁻¹ × 0.750 L)

                     Molarity  =  0.385 mol.L⁻¹

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