Chemistry, 05.07.2019 20:10 hipstersale4913
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.
Answers: 2
Chemistry, 22.06.2019 20:00
There are two steps in the usual industrial preparation of acrylic acid, the immediate precursor of several useful plastics. in the first step, calcium carbide and water react to form acetylene and calcium hydroxide: cac2 (s) + 2h2o (g) → c2h2 (g) + caoh2 (s) =δh−414.kj in the second step, acetylene, carbon dioxide and water react to form acrylic acid: 6c2h2 (g) + 3co2 (g) + 4h2o (g) → 5ch2chco2h (g) =δh132.kj calculate the net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxide from these reactions. round your answer to the nearest kj .
Answers: 3
Chemistry, 23.06.2019 02:40
Calculate the standard enthalpy of formation of liquid methanol, ch3oh(l), using the following information: c(graphite) + o2 latex: \longrightarrow ⟶ co2(g) latex: \delta δ h° = –393.5 kj/mol h2(g) + o2 latex: \longrightarrow ⟶ h2o(l) latex: \delta δ h° = –285.8 kj/mol ch3oh(l) + o2(g) latex: \longrightarrow ⟶ co2(g) + 2h2o(l) latex: \delta δ h° = –726.4 kj/mol
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Chemistry, 23.06.2019 15:00
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Answers: 1
Radon gas as rn-222 is formed by the radioactive decay of u-238, the chief natural isotope of uraniu...
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