The first one is a bit more natural without the 'the', but it makes sense either way.
The second shouldn't have a 'the' at all though.
"What time is (the) practice tomorrow?"
"What time is tomorrow's practice?"
Also, the title should say 'sentences' as a plural. Normally it should be have an 'are' as well, but sentence fragments aren't uncommon in titles.
Hope that helped.