What is schwa vowel in cement?

Answer 1

Depends on the dialect or variety of English. In some American varieties the second "e" is somewhat elided, therefore turning the "e" into a schwa, since the first syllabal is stressed. In Australian English, the first "e" is elided ("c'ment") so, yes there can be a schwa in "cement". Just look at which syllable is stressed (it does vary from one variety of English to another) then the other is likely to contain a schwa (or elided vowel).