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    Hi Guys,
    for a reaction equation if you want to find out the energy released do you have to calculate the change in mass first and then use it in the equation E=mc^2 in order to find out the energy released?the question is on the attachment below. please have a look at it and let me know what you think thanks
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    Yes, you need to calculate the difference in mass between the reactants and products. This mass difference can be converted into the energy released using E = mc^2.

    Alternatively, as you are given the mass in terms of u, you can find the mass in terms of u and use the conversion 1 u = 931.5 MeV/c^2 to find the energy released in MeV.
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    (Original post by AlesanaWill)
    Yes, you need to calculate the difference in mass between the reactants and products. This mass difference can be converted into the energy released using E = mc^2.

    Alternatively, as you are given the mass in terms of u, you can find the mass in terms of u and use the conversion 1 u = 931.5 MeV/c^2 to find the energy released in MeV.
    So basically should i convert that nuclear mass given in the question to MeV first and then takes it from there? Or is it not nessecarry ?
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    (Original post by Alen.m)
    So basically should i convert that nuclear mass given in the question to MeV first and then takes it from there? Or is it not nessecarry ?
    Convert all the masses into units of u and find the mass difference. The energy released is then 931.5 multiplied by this value, in MeV. (Assume the neutrino is massless.)
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    (Original post by AlesanaWill)
    Convert all the masses into units of u and find the mass difference. The energy released is then 931.5 multiplied by this value, in MeV. (Assume the neutrino is massless.)
    So masses has to be in the u unit all the time?
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    (Original post by Alen.m)
    So masses has to be in the u unit all the time?
    The conversion to kg in the definitions sheet doesn't have enough significant figures. see MS. http://filestore.aqa.org.uk/subjects...MS-JUN13.PDF#4

    tbh I think that's a bit of a shady way of denying a mark but I guess that's how the examiner wants you to play it.
 
 
 
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