Is it demanding to ask for a little more phone time?

I think 30-40 minutes every single day is a lot of time already... considering she's in law school. I think you should really cut her some slack. Be thankful she's atleast acknowledging your existence and isn't neglecting you. She's doing her best, but you have to realize her priority is law school. And after law school, it will be you.

I guess not. But, she might just be stressed or frustrated with school, and therefore gets a little disturbed when she needs to go and study. If you are talking everyday for 30-40 minutes, I think that is fine. Some couples don't get to talk everyday like that. Maybe you guys can try and keep it touch other ways throughout the day- email, text messages, instant messangers, letters (if anyone does that anymore LOL!), etc.

what is the reason for her getting off the phone? on the flip side, would getting 5 more minutes lead to you wanting more and more time on the phone, also are you using the whole time to talk to her, or does the conversation die out after 20 - 30 minutes?

Is it wrong? No, but law school is a powerful commitment. One day you two will be together, once she's finished though. She has to find where she wants to be in life for herself, then she can find her place with you

no....i would think she would want to give you as much time at possible....see if she can stay on the phone longer or call you again latter to talk....