Nuclear energy involves the controlled harvesting of energy from fission reactions. If this energy could be properly harvested, it would be a significant source of energy for our society. Nuclear reactions give off billions of kilojoules per mole. Compare it to combustion reactions of hydrocarbons, which give off about 650 kJ/mol of energy for every CH 2 unit in the hydrocarbon - on the order of hundreds of kilojoules per mole. This is an extraordinary amount of energy. (For the units to work out, mass must be expressed in units of kilograms.) That is, 16.5 billion kJ of energy is given off every time 1 mol of uranium-235 undergoes this nuclear reaction. In the course of the chemical reaction for uranium, the mass difference is converted to energy, which is given off by the reaction: Where c is the speed of light, or 3.00 × 10 8 m/s. Where did this mass go?Īccording to Albert Einstein’s theory of relativity, energy ( E) and mass ( m) are related by the following equation: If we compare the mass of the reactant (235.0439) to the masses of the products (sum = 234.8605), we notice a mass difference of −0.1834 g, or −0.0001834 kg. Consider the following nuclear equation, in which the molar mass of each species is indicated to four decimal places:
Where does this energy come from? If we could precisely measure the masses of the reactants and products of a nuclear reaction, we would notice that the amount of mass drops slightly in the conversion from reactants to products. Nuclear changes occur with a simultaneous release of energy.
Describe the difference between fission and fusion.Explain where nuclear energy comes from.
0 kommentar(er)
