Free energy from Thorium to Radon

[Xeno24]

228 224 4
Th --> Ra + He
90 88 2228,031015u --> 224,020186u + 4,0026033u

228,031015u - [224,020186u + 4,0026033u]=

0,0082257u

0,0082257u x 931.49 MeV = 7662157,293eV

7662157,293eV x (1.602 x 10^-19J) =

1,2274776 x 10^-12J

Svar: Frigjorda energin är: ~ 1.23 x 10^-12JHi, people could anyone check what I've done wrong here? My teacher says the answer value is a bit too high. It's just arithmetic and I've still done something wrong...I tried multiplying the (0,0082257u) with (1.66 x 10^-27) x C^2 and I still get ~ 1.23 x 10^-12J

Thanks.

 

[Andrew Mason]

228 224 4
Th --> Ra + He
90 88 2228,031015u --> 224,020186u + 4,0026033u

228,031015u - [224,020186u + 4,0026033u]=

0,0082257u

0,0082257u x 931.49 MeV = 7662157,293eV

7662157,293eV x (1.602 x 10^-19J) =

1,2274776 x 10^-12J

Svar: Frigjorda energin är: ~ 1.23 x 10^-12JHi, people could anyone check what I've done wrong here? My teacher says the answer value is a bit too high. It's just arithmetic and I've still done something wrong...I tried multiplying the (0,0082257u) with (1.66 x 10^-27) x C^2 and I still get ~ 1.23 x 10^-12J

Thanks.

Your answer appears to be right.

From E = mc^2:

Just multiply the mass difference in kg. by c^2 in m/sec. to get the energy in joules

Mass difference is 8.226x10^-3 amu. One kg = 1000 x 6.02x10^23 amu so one amu = 1.66 x 10^-27 kg. Multiply that by (3 x 10^8 m/sec)^2 to get the energy in J. per amu. (= 1.49 x 10^-10 J.). So that works out to 8.266x10^-3 x 1.49 x 10^-10 = 12.3 x 10^-13 J = 1.23x10^-12 J.

AM

 

[nlightner]

Hi there, thank you for providing your work. I see that you have correctly calculated the difference in mass between thorium and radon and converted it to energy using the equation E=mc^2. However, the issue may be in your conversion from atomic mass units (u) to kilograms (kg). The conversion factor you used (1.66 x 10^-27) is for converting from atomic mass units to kilograms, but you also need to convert from kilograms to joules. This can be done by multiplying by the speed of light squared (c^2), which is 8.99 x 10^16 m^2/s^2. So the correct conversion factor would be (1.66 x 10^-27) x (8.99 x 10^16) = 1.49 x 10^-10. Using this conversion factor, the final answer would be 1.22 x 10^-13 J, which is closer to the expected value. I hope this helps clarify the issue.