chemistry
The Italian word 'chimica' is used much in the same way as 'chemistry' in English. It can represent both the physical science, as in 'I'm studying chimica at university' and the interpersonal connection between people, as in 'there's a certain chimica between them.'
I am studying chemistry for tomorrow's exam.
This sentence is used to express that the speaker is currently studying chemistry in preparation for an exam that they have the following day. 'Sto studiando' is the present progressive form of the verb 'studiare', meaning to study. 'Per' is a preposition meaning 'for' and 'l'esame di domani' means 'tomorrow's exam'.
Chemistry is a very interesting subject.
This sentence is used to express a personal opinion about the subject of chemistry. 'È' is the third person singular present of the verb 'essere', meaning 'is'. 'Una materia molto interessante' means 'a very interesting subject', where 'una' is an indefinite article, 'materia' means 'subject', 'molto' means 'very', and 'interessante' means 'interesting'.
Chemistry deals with the study of substances and their reactions.
This sentence is a straightforward explanation of what chemistry is about. 'Si occupa' is a reflexive verb phrase that means 'deals with'. 'Dello studio' is a prepositional phrase meaning 'of the study'. 'Delle sostanze e delle loro reazioni' means 'of substances and their reactions', where 'delle' is a preposition meaning 'of the', 'sostanze' means 'substances', 'loro' means 'their', and 'reazioni' means 'reactions'.