Правильно ли написаны вопросы? 1) What does the term "сollege" mean? 2) What is a liberal art institutions? 3) what is community college? 4) What is the academic calendar for university in the US? 5) why not so easy to stay in university?

1) What does the term "сollege" mean? - correct;

2) What are liberal art institutions? - without "a", as the Noun is in plural ("institutions");

3) What is a community college? - with "a", as the Noun is in singular ("college");

4) What is the academic calendar for a university in the US? - with "a", as the Noun is in singular ("university") and has the meaning "any";

5) Why is it not so easy to stay in university? - introductory "it is" in the converted form (as it's a question) is omitted.