A chemistry graduate student is given 300. mL of a 0.20 M ammonia (NH_3) solution. Ammonia is a weak base with K_b = 1.8 times 10^-5. What mass of NH_4 Br should the student dissolve in the NH3 solution to turn it into a buffer with pH = 9.10? You may assume that the volume of the solution doesn't change when the NH4Br is dissolved in it. Be sure your answer has a unit symbol, and round it to 2 significant digits.

where is the following

explanation:

catya that's not even a b or c

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.