Question

find the mass of 0.5 mole of Na2CO3

Answer 1

molecular mass of Na,C and 0 are respectively 23u, 12u and 16u respectively.

so mass of 2*Na=2*23=46u
mass of 3*O=3*16=48u

so molecular mass of Na2CO3=46u+12u+48u
=106u
so mass of 1 mole of Na2CO3=106gms
so mass of 0.5 mole of Na2CO3=0.5*106gms
=53gms

hence mass of 0.5 mole of Na2CO3 is 53gms.

Answer 2

See the attachment.....