Resposta :
Olá!:
a ) H₂CO₃ = ( 1 x 2 ) + ( 12 x 1 ) + ( 16 x 3 ) => 62 g/mol
b) SO₂ = ( 32 x 1 ) + ( 16 x 2 ) => 64 g/mol
c) Mg(NO₃)₂ = ( 24 x 1 ) + ( 14 x 2 ) + ( 16 x 6 ) => 148 g/mol
d) Na(OH)₂ = ( 23 x 1 ) + ( 16 x 2 ) + ( 1 x 2 ) => 57 g/mol
Espero ter ajudado!