The combustion of a hydrocarbon x (30 cm3) with 350 cm3 of oxygen at stp resulted in the formation of 440 cm3 of gaseous products. the volume of gases was reduced to 360 cm3 when the excess o2 was removed and then reduced by half when bubbled through naoh.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.