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2+ Year Member
Jan 25, 2016
Hey guys,

So I was going over the video explanation for #16 on Bootcamp for Test 4 Gen Chem. I hope I'm not violating any rules, but I'll post just the question here:

"A small amount of aqueous NH3 is added to a solution of Cu2+ and a precipitate forms. However, when excess aqueous NH3 is added, the former precipitate dissolves. Which statement best explains why the precipitate dissolves with excess aqueous NH3?"

In the explanation, he first says that there will be a precipitate formed in dilute NH3, but then at the end of the video when he lists his bullet-summary, he says the exact opposite "No precipitation occurs with our dilute NH3 conditions". He does the same with the excess NH3 explanation, too.

Can anyone help clarify where my thinking is flawed? Or does he really contradict himself? It's 99.9% me, but I just need a differently worded explanation, I suppose, since I can't seem to grasp the concept.
Jan 9, 2015
Well I can't really help by just looking at what you wrote here without the choices and everything that he said. It seems there's a contradiction to what he said. I need to see the whole picture.
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