tolong jawabin nomor 1,2,3 yaaa, soalnya butuh bangett. sama caranya yaa

1. a. Mr = ArH + ArN + 3xArO
= 1 + 14 + 3×16
= 63
b. Mr = ArNa + ArO + ArH
= 23 + 16 + 1
= 40
3. 3H2 + N2 => 2NH3
2Mg + O2 => 2MgO