Tom and Jerry episode where karate chops a brick?

You're likely thinking of the classic Tom and Jerry episode "Karate Kid" (1965).

In this episode, Tom attempts to learn karate from a book. He practices his moves, but with disastrous results, often ending up hurt. At one point, he tries to chop a brick in half, but ends up cracking his own skull.

Let me know if you'd like to know more about that episode or other Tom and Jerry cartoons!