How do you calculate the number of grams in 1.023 moles?
You have specified a molar quantity; you have NOT specified a molar mass.
Given a Periodic Table, we can immediately quote the molar mass of a given atom or molecule simply by summing up the individual molar masses. However, you have not specified what constitutes your molar quantity; it could be hydrogen atoms or molecules or nitrogens or methane molecules or something. So while we know the NUMBER of particles, we do not know the IDENTITY of the particles.