Is there a specific amount that must be recited in the Tarawih prayer?

There is no specific measure for the recitation in Tarawih prayer, and it is better to prolong it as long as it does not cause hardship to the congregants. The recitation of the Prophet, peace be upon him, varied in length, sometimes he would recite the length of (Surah Al-Muzzammil) and other times fifty verses. It is authentically reported that he recited the seven long surahs, and in one rak'ah he recited (Al-Baqarah) then (An-Nisa) then (Al 'Imran). 'Umar, may Allah be pleased with him, used to command Ubayy ibn Ka'b to recite by the hundreds [of verses], to the extent that the worshippers would lean on their staffs due to the length of the standing. If a Muslim prays alone, he may prolong as he wishes, but the imam should lighten the prayer in a way that does not cause hardship to those behind him.