[luketapis]

The mass of the 3He nucleus is 3.014932 u. Calculate the nuclear binding energy (kJ) of 1 mole of this nucleus, given the mass of the proton is 1.00728 u and the mass of the neutron is 1.00866 u.

Ok I know I have to use that formula
E=mc^2
But do I need to chage the mass into kilos?

[gvsu88]

I think you're in my class cause I just did that problem. Anyway, just find the theoretical mass of the Helium. 2 x mass of proton + 1 x mass of neutron. Find the difference between that value and the given value for mass of He-3. Then convert that mass to kg. 1 amu = 1.66e-27 kg. Then plug it into the Einstein equation.

[Borek]

Ok I know I have to use that formula
E=mc^2
But do I need to chage the mass into kilos?

If you use some other mass unit your final result will be not in Joules - as Joul is kg*m²/s². It doesn't have to be a problem, as you may be able to convert energy to Joules later - but converting mass to kg at the very beginning will probably make your work easier.

[luketapis]

So the different in mass is 8.288 x10^-3. then I have to multiply that by 1.66 x 10^-27 and put into the equations? Like that:

8.288 x 10^-3 x 1.66 x 10^-27=1.375808 x 10^-29
then
if E=mc² 
E=1.375808 x 10^-29 x 2.99792458 x 10⁸=4.124568621 x 10^-21kJ

Am I right?