Polonium-210, a naturally occurring radioisotope, is an alpha emitter, with t1/2=138 d. Assume that a sample fo 210Po with a mass of 0.700 mg was placed ina 250.0-mL flask, which was evacuated, sealed, and allowed to sit undisturbed. What would the pressure be inside the flask (in mmHg) at 20 degrees Celsius after 365 days if all the alpha particles emitted has become helium atoms?

Imagine that you have a 0.007 50 M aqueous MgCl2 solu-tion, prepared so that it contains a small amount of radio-active 28Mg. The half-life of 28Mg is 20.91 h, and the initial activity of the MgCl2 solution is 0.112 mCi>mL. Assume that 20.00 mL of this MgCl2 solution is added to 15.00 mL of 0.012 50 M aqueous Na2CO3 solution and that the resultant precipitate is then removed by filtration to yield a clear filtrate. After a long break to go for a run, you find that the activity of the filtrate measured 2.40 h after begin-ning the experiment is 0.029 mCi>mL. What are the molar concentrations of Mg2+ and CO32- in the filtrate, and what is the solubility product constant of MgCO3?

A small sample of wood from an archaeological site in Clo-vis, New Mexico, was burned in O2 and the CO2 produced was bubbled through a solution of Ba(OH)2 to produce a precipitation of BaCO3. When the BaCO3 was collected by filtration, a 1.000 g sample was found to have a radioactivity of 4.0 x 10^-5 Bq. The half-life of 14C is 5715 y, and living organisms have a radioactivity due to 14C if 15.3 disintegrations/min per gram of carbon. If the analysis was carried out in 1960, what is the date of the Clovis site?

A proposed nuclear theory suggests that the relative abun-dances of the uranium isotopes 235U and 238U were approximately equal at the time they were formed. Today, the observed ratio of these isotopes is 7.25 x 10^-3. Give that the half-lives for radioactive decay are 7.04 x 19^8 are y for and 4.47 x 10^9 y for , calculate the age of the elements.