A salt is dissolved in water. The results of two separate tests on it are shown in the table.
1. white precipitate which is soluble when excess aqueous ammonia is
added.
2. white precipitate is formed when dilute nitric acid and aqueous
barium nitrate is added to the salt solution. What is the salt?

c. 75.7

i think that is the right

the answer is barium and copper bromide

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.