Question 2 (10 pts): In the COD measurement of a raw wastewater sample, initial K2Cr2O7 concentration added into the wastewater sample is 3.000 g/L. After the redox reaction has reached an equilibrium, the K2Cr2O7 concentration has been reduced to 1.824 g/L. Assuming in the redox reaction, the Cr in K2Cr2O7 is reduced to Cr3 . What is the COD of the wastewater sample in mg/L

one state would change   like louisiana to texas. thats a change

explanation:

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.