An atom of uranium-235 isotope releases nuclear energy equivalent to 3.3 x 10-11 J. Assume a tonne of coal releases thermal energy equivalent to about 5 x 107 J. Calculate the mass of coal needed to be burnt in a power plant to produce the energy equivalent to 1 g of uranium-235 isotope in a nuclear reactor ignoring heat losses. 1 mole of uranium-235 isotope = 6.0221367 x 1023 atoms = 235 g