91影视

Given activity is 0.18 i (Becquerel, Bq), which means 0.18 alpha particles are emitted per second. To find the total number of alpha particles emitted during 245 days, we need to multiply the activity by the number of seconds in 245 days. Seconds in 245 days: 1 day = 24 hours 1 hour = 60 minutes 1 minute = 60 seconds Therefore, \(245 \,days \times 24\,h/day \times 60\,min/h \times 60 \,s/min = 21168000 \,s\) Now, multiply the activity by the number of seconds: \(number \,of \,alpha \,particles = activity \times time = 0.18\,Bq \times 21168000\,s = 3804240\) So, the total number of alpha particles emitted during 245 days is 3,804,240 alpha particles.

Assuming that each alpha particle becomes a helium atom, we can calculate the number of moles of helium atoms formed using Avogadro's number: \(number \,of\,moles = \frac{number\,of\,atoms}{Avogadro's\,number}\) \(number\,of\,moles\,of\,helium = \frac{3804240}{6.022\times10^{23}\,atoms/mol} = 6.318\times10^{-19}\,mol\) Now, we can use the ideal gas law formula (PV = nRT) to find the partial pressure of helium gas. But first, we need to convert the temperature given in Celsius to Kelvin. Temperature in Kelvin: \(T(K) = T(^\circ C) + 273.15 = 22^\circ C + 273.15 = 295.15\,K\) The volume of the container is given as 25.0 mL, which we need to convert to L. Volume in L: \(V(L) = 25.0\,mL \times \frac{1\,L}{1000\,mL} = 0.025\,L\) And we need to use the gas constant R in appropriate units, which is: \(R = 0.0821\,atm\,L/mol\,K\) Now using the ideal gas law formula and solving for pressure, we have: \(P = \frac{nRT}{V}\) \(P = \frac{(6.318\times10^{-19}\,mol)(0.0821\,atm\,L/mol\,K)(295.15\,K)}{0.025\,L}\) \(P = 5.20\times10^{-17}\,atm\) So, the partial pressure of helium gas in the container after 245 days is 5.20 x 10鈦宦光伔 atm.