can somebody help name these compounds?

9. methanoic acid

10. N-ethylethanamide

11. methyl ethanoate

12. 2-propanol (U.S) / propan-2-ol (Brit.)

13. 2-butyne (U.S.) / but-2-yne (Brit.)

14. methylbutane / 2-methylbutane
(There is no ambiguity for the methyl group at position 2.)

15. N,N-dimethylethanamine / N,N-dimethylethylamine
(Suppose that a H atom is missed.)