My 10 year granddaughter lives with us, but her attitude is very bad. What can we do to correct it?

If you ask her a question of any kind, she acts like you are just really bothering her and responds in such a awful tone. I know she is going trough a ruff time with the situation with her Mom and Dad only being in her life on a part time bases. I have tried to talk with her about her attitude and tone of voice but nothing I have said to her has changed the way she acts. She gets good grades and doesn't have problems at school. She also talks to her parents the same way.