1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Simple percentage problem

  1. Aug 10, 2009 #1
    1. The problem statement, all variables and given/known data

    In the following exoergic nuclear reaction,

    12D + 13T &rarr 01n + 24He

    what percentage of the initial mass is converted into energy?

    2. Relevant equations

    (mA +ma)- (mB-mB) =delta m

    delta m * u(MeV) = E

    3. The attempt at a solution

    I'm not sure how to do sub and super scripts but 12D would be deuterium. Anyway I calculted the masses and got (mA+ma)5.03u for the first and (mB+Mb)5.011 for the second. To get the % of the mass converted to energy I divided mb+mB/mA+mA and got 99.6%. A I doing it correctly...(even if I calculated the masses incorrectly)
  2. jcsd
  3. Aug 10, 2009 #2


    User Avatar

    The number you got, 99.6% (assuming the masses and the arithmetic are right), is the percentage of the original mass *not* converted to energy.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook