[aliaja]

Hello, all. I'm going over some practice problems and I am having trouble understand why the answers are what they are. I've learned that to determine a coupling constant, you multiply the chemical shifts by the strength of the NMR spectroscope and subtract the two, but it seems to be more complicated since I'm clearly not getting the correct answer. I'm also confused as to how they determined the chemical shifts in this problem. Any help is appreciated.

http://i49.tinypic.com/am5q48.png

[willug]

I'm not surprised you're having trouble! Try to assign the signals yourself without looking at what is written (it's not right).

[Big-Daddy]

Write out your attempts here including Hz -> delta PPM calculations and we can try and scrutinize for mistakes.

[orgopete]

Don't make ths too complicated. The frequencies are already in Hz. The coupling constants are the difference in frequencies of coupled peaks in Hz. Just subtract. The chemical shift (in ppm) will require a calculation.