A student fails Chemistry because they didn't study and didn't learn all they needed to learn to pass the tests.
Reason why computer Engineering student fail?
No, there is no reason why you should fail in this case.
no
No, this is not obligatory.
It depends on what you mean. If you mean "more likely to fail chemistry and physics than to fail mathematics", then the answer is presumably yes. If you mean "more likely to fail chemistry and physics than some bozo who can't figure out how this 'multiplication' thing works", then no. In physics and (most kinds of) chemistry, a solid understanding of mathematics can only be helpful.
No, a teacher cannot fail a student without providing a valid reason.
If there isn't good chemistry between the teacher and the student, the student won't be able to learn well.
you wont always fail
Not true. Chemistry is easier than Mathematics.
If you don't do your homework -- yes, it will cause you to fail. Doing homework will not cause you to fail.
No.
Not you will but you can.