。
I hate chemistry.
Literal
Chemistry [subject-が] disliked [copula-だ].
Like 好き, the opposite 嫌い is a na-adjective and takes が to mark the object of dislike — the thing disliked is grammatically the *subject*, not a direct object. This が-marking pattern is standard for emotions and preferences (好き, 嫌い, 怖い, 上手, 下手, etc.). 嫌い carries strong negative feeling; 苦手 is a softer alternative meaning 'not good at / not a fan of.'