11.5 cm3 of a gaseous hydrocarbon were exploded with excess oxygen and there was a diminution in volume of 34.5 cm3 and on absorption with KOH solution there was a further reduction in volume of 34.5 cm3. What is the molecular formula of the hydrocarbon? (All measurements were made at room temperature and pressure.)

Because a model would make the investigation easier to understand

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.