The breakdown of dopamine is catalyzed by the enzyme monoamine oxidase (MAO). What is the final concentration of product if the starting dopamine concentration is 0.050 M and the reaction runs for 5 seconds. (Assume the rate constant for the reaction is 0.249 s^-1.)

A) 0.050 M
B) 0.014 M
C) 0.018 M
D) 1.2 M
E) 0.025 M

The answer is: B) 0.014 M

Explanation:

The reaction is the first order, then:

Where

Ct = concentration in any time

Co = initial concentration = 0.05 M

K = 0.249 s⁻¹

t = 5 s

Replacing:

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.