Answer:
Step-by-step explanation:
MOLECULAR MASS = ∑ the elements atomic mass from the periodic table
1st NaO
molecular mass = atomic mass of Na + Atomic mass of O
= ( 23 + 16 ) = 39 g/mol
2nd : AlCl3
M.m = atomic mass of Al + Atomic mass of 3Cl
( 27 + 3x35.5 )= 97 g/mole
3rd : Na3(SO4)
M.mass = atomic mass of 3 Na + atomic mass of S + atomic mass of 4 O
( 3x23) + 32 + (4 x 16) =165 g/mol
4th : Mg(OH)2
M.mass = atomic mass of Mg + atomic mass of 2 O + atomic mass of 2
= 24 + 2x16 + 2x1 = 58 g/mol