Question

Define mole. Calculate the molar mass of
H₂, Cl₂, O₂, CO₂, CH₄, NH₃, P4​

Answer 1

Answer:

i) Molecular mass of H2= 2 x Atomic mass of H= 2 x 1

= 2 u

ii) Molecular mass of O2= 2 x Atomic mass of O

= 2 x 16

= 32 u

iii) Molecular mass of Cl2= 2 x Atomic mass of Cl

= 2 x 35.5

= 71 u

iv) Molecular mass of CO2= Atomic mass of C + 2 x Atomic mass of O

= 12 + 2 x 16

= 44 u

v) Molecular mass of CH4= Atomic mass of C + 4 x Atomic mass of H

= 12 + 4 x 1

= 16 u

vi) Molecular mass of C2H6= 2 x Atomic mass of C + 6 x Atomic mass of H

= 2 x 12 + 6 x 1

= 30 u

vii) Molecular mass of C2H4= 2 x Atomic mass of C + 4 x Atomic mass of H

= 2 x 12 + 4 x 1

= 28 u

viii) Molecular mass of NH3= Atomic mass of N + 3 x Atomic mass of H

= 14 + 3 x 1

= 17 u

ix) Molecular mass of CH3OH= Atomic mass of N + 3 x Atomic mass of H

= 12+ 4 x 1+16

= 32 u

Explanation:

hope this will help you

Answer 2

i) Molecular mass of H2= 2 x Atomic mass of H= 2 x 1

= 2 u

ii) Molecular mass of O2= 2 x Atomic mass of O

= 2 x 16

= 32 u

iii) Molecular mass of Cl2= 2 x Atomic mass of Cl

= 2 x 35.5

= 71 u

iv) Molecular mass of CO2= Atomic mass of C + 2 x Atomic mass of O

= 12 + 2 x 16

= 44 u

v) Molecular mass of CH4= Atomic mass of C + 4 x Atomic mass of H

= 12 + 4 x 1

= 16

vi) Molecular mass of NH3= Atomic mass of N + 3 x Atomic mass of H

= 14 + 3 x 1

= 17 u

vii) P4 (atomic mass of phosphorus = 31)

Molar mass of phosphorus molecule, P4 = 4 x 31 = 124 g