The energy that a log has is transformed when burned. how does the chemical energy of the log compare to the heat and light energy it is transformed into?

the amount of chemical energy is equal to the amount of heat and light energy.

the amount of chemical energy is less than the amount of heat and light energy.

the amount of chemical energy is more than the amount of heat and light energy.

there is no way to know.

I believe the correct answer from the choices listed above is the second option. The chemical energy of the log compare to the heat and light energy it is transformed into would be the amount of chemical energy is less than the amount of heat and light energy. 

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant.