Calculate the molecular masses of H 2 , O 2 , Cl 2 , CO 2 , CH 4 , C 2 H 6 , C 2 H 4 , NH 3 , CH 3 OH
Answer
Atomic mass of H =1 u
Atomic mass of O = 16 u
Atomic mass of Cl = 35.5 u
Atomic mass of C = 12u
Atomic mass of N= 14 u
Molecular mass of H 2 = 2 x Atomic mass of H
= 2 x 1u
= 2u
Molecular mass of O 2 = 2 x Atomic mass of O
= 2 x 16u
= 32u
Molecular mass of Cl 2 = 2 x Atomic mass of Cl
= 2 x 35.5u
= 71u
Molecular mass of CO 2 = 1x Atomic mass of C + 2 x Atomic mass of O
= 1 x 12u + 2x16u
= 12u+32u
= 48u
Molecular mass of CH 4 = 1x Atomic mass of C + 4 x Atomic mass of H
= 1 x 12u + 4x1u
= 12u+4u
= 16u
Molecular mass of C 2 H 6 = 2x Atomic mass of C + 6 x Atomic mass of H
= 2 x 12u + 6x1u
= 24u+6u
= 30u
Molecular mass of C 2 H 4 = 2x Atomic mass of C + 4 x Atomic mass of H
= 2 x 12u + 4x1u
= 24u+4u
= 28u
Molecular mass of NH 3 = 1x Atomic mass of N + 3 x Atomic mass of H
= 1 x 14u + 3x1u
= 14u+3u
= 17u
Molecular mass of CH 3 OH = 1x Atomic mass of C + 4 x Atomic mass of H + 1 x Atomic mass of O
= 1 x 12u + 4x1u + 1 x 16u
= 12u+4u+16u
= 32u
