Yes, ADEQUATENESS is a Scrabble word!

Letter values in Scrabble US: A 1, D 2, E 1, Q 10, U 1, A 1, T 1, E 1, N 1, E 1, S 1, S 1.

Is it a valid word?

ADEQUATENESS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

the quality of being able to meet a need satisfactorily: "he questioned the adequacy of the usual sentimental interpretation of the Golden Rule"