What is the equilibrium expression for 2NO+Br2⇌2NOBr?

A) [NO2][Br]2/[NOBr2]
B) [NOBr]2/[NO2][Br]2
C) [NO]2[Br2]/[NOBr]2
D) [NOBr]2/[NO]2[Br2]

D?

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.

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