Fossil fuels store energy that is released when they are burned. what is the origin of the energy contained in fossil fuels? the wind water ores the sun

If a balloon is taken outside on a very cold day, what will occur?

5. why should the electrons be placed separate from each other (why not together)?

In a particular chemical reaction, the energy of the reactants is 30 kj and the energy of the products is 5 kj. 
 the maximum energy of the system is 40 kj. sketch a potential energy diagram for this reaction. make sure to label the energy of the reactants, the energy of the products, the activation energy, and the enthalpy change for the reaction.