Qt 5 doesn't break any major usage pattern regarding Qt 4. So most of what was valid for Qt 4 is still valid for Qt 5.
AFAIK, there are no specific exercices to do for the Qt exams because the exams themselves tests the experience you acquired using the framework. There's no strange exotic corner case questions.
You can find more information about them here as well as the associated curriculums which describe what you should know and understand in order to succeed the exams.