Explain how the heat measured in example 5.5 diffees from enthalpy change for the exothermic reactions described by the following equation:
hcl + naoh ? nacl + h2o
reference example 5.5
heat produced by an exothermic reaction
when 50.0ml of 0.10 m hcl and 50.0 ml of 0.10 m naoh, both at 22.0c are added to a cofee cup calorimeter, the temperature of the mixture reaches a maximum of 28.9 c. what is the approximate amount of heat produced by this reaction
hcl + naoh ? nacl + h2o

Most smaller stars don't have a radiative zone.

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.