The thermite reaction was used to produce molten iron for welding applications before arc welding was available.
The thermite reaction is:
Fe2O3(s)+2Al(s)→Al2O3(s)+2Fe(l)
How many moles of molten iron can be produced from 1.7 kg of iron(III) oxide?
Use unit of substance

21.2912 moles of molten iron will be produced from 1.7 kg of Fe203.

Explanation:

From the equation:

Fe2O3(s)+2Al(s)→Al2O3(s)+2Fe(l)

it is found that 1 mole of Fe203 will undergo thermite reaction to yield 2 moles of molten iron.

The weight of Fe203 given is 1.7 kg OR 1700 Grams

The atomic weight of the Fe2O3= 159.69

Number of moles can be calculated as= 1700/159.69

                                                                  =  10.64 moles of Fe2O3

So, from stochiometry,

1 mole Fe2O3 yield 2 moles of Fe

so 10.64 moles will yield x mole of Fe

2/1=x/10.64

x= 21.2912 moles

Thus, 21.2912 moles of molten iron will be produced from 1.7 kg of Fe203.

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.