How many moles of o2 are needed to react with 24 moles of c2h6?

The number of moles  of O2 that are needed  to react  with  24 moles  of C2H6  is   84 moles of O2

 Explanation

Step 1: write the equation  for reaction

=  2C2H6  +7O2 →  4CO2  + 6H2O

Step 2:  use  the mole ratio to determine the moles  of O2

that is the mole  ratio  of C2H6 : O2  is  2:7 therefore the  moles of O2= 24 x7/2=  84  moles  of O2

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.