How many grams of Barium are in 1.746g of BaCO3?

Answer 1

Mass of Elements (AMU - Atomic Mass Units):
Ba = 137∙34
C = 12∙01
O = 16∙00

BaCO3 = 137∙34 + 12∙01 + (16∙00 x 3)
BaCO3 = 137∙34 + 12∙01 + 48∙00
BaCO3 = 197∙35

No. of grams of Barium:
Ba = Mass of compound x [AMU of Ba / AMU of Compound]
Ba = 1∙746g x [ 137∙34 / 197∙35]
Ba = 1∙215 077 983
Ba ≈ 1∙215g

Answer 2

What is the molar weight of BaCO3?

The percentage of the 1.746g that is Ba is the same percentage of the molar weight of Ba to the molar weight of BaCO3.

I mean, you haven't been given this question of of the blue. You must have solved a problem something like this.