Is the word química the same in Brazilian and European Portuguese?

Yes

The only difference between the use of "química" in Brazilian Portuguese and Continental Portuguese is pronunciation. The word's meaning (both the scientific study of matter and the metaphorical concept of interpersonal attraction), spelling, grammar, and typical usage are identical in both dialects.

In Brazilian Portuguese, the vowels are generally more open, and the rhythm is more "syllable-timed," meaning each syllable receives a relatively clear and distinct articulation. In Continental Portuguese, unstressed vowels are often more "reduced" or closed, which can make the word sound more clipped or shorter to a non-native ear.

Brazilian Portuguese Examples

1. Eu adoro a aula de química. (I love chemistry class.)
2. Eles têm uma química muito forte. (They have a very strong chemistry.)
3. A química dos materiais é complexa. (The chemistry of the materials is complex.)
4. Não senti nenhuma química entre nós. (I didn't feel any chemistry between us.)
5. O laboratório de química está fechado. (The chemistry laboratory is closed.)

Continental Portuguese Examples

1. Eu adoro a aula de química. (I love chemistry class.)
2. Eles têm uma química muito forte. (They have a very strong chemistry.)
3. A química dos materiais é complexa. (The chemistry of the materials is complex.)
4. Não senti nenhuma química entre nós. (I didn't feel any chemistry between us.)
5. O laboratório de química está fechado. (The chemistry laboratory is closed.)