Oaths & Vows

Making a vow in one's mind

Q: I made a niyat of doing a sacrifice. If one of my problems is solved then I will sacrifice this thing in front of Allah. But I want to take that back before my problem gets solved because I think I will break this niyat or promise after my problem is solved.

Breaking an oath

Q: One of my friends was a chain smoker until recently. Even after many attempts he was unable to give up smoking. Finally one day he took an oath by holding Quran paak in his hand that he would never smoke again. But after few days he started smoking again. So what is the kaffara of the oath which he took on Quran. 

Unmarried woman taking an oath that if she does something then her nikaah will break

Q:

1. If before giving the marriage consent in front of witnesses a girl takes an oath that if she does a certain thing her nikaah is invalid but she breaks the above oath when she is married ...is her nikaah valid?

2. If after giving the marriage consent in front of witnesses a girl takes an oath that if she does a certain thing her nikaah is invalid but she breaks the above oath when she is married ...is her nikaah valid?

Taking a false oath

Q: I smoked weed once or twice which I am not sure is haraam or not. Anyways recently my mother found it out from my bag. It wasn't mine and she made me swear upon her head and the quran that I haven't ever smoked weed in my life and I did. Please tell me did I do wrong by taking a false oath and what penalty I have to pay for forgiveness? If I hadn't done it, she might be heartbroken.