Question

Calculate the molar mass of the following:
(i) H2O (ii) CO2 (iii) CH4

Answer 1

(i)molecular mass of H2O

=2×1+16

=2+16

=18 u

molar mass of H20=18 gmol^-1

(ii)molecular mass of CO2

=12+2×16

=12+32

=44 u

molar mass of CO2=44 gmol^-1

(iii)molecular mass of CH4

=12+4×1

=12+4

=16 u

molar mass of CH4=16 gmol^-1

Answer 2

Answer:

(i) H2O:

The molecular mass of water, H2O

= (2 × Atomic mass of hydrogen) + (1 × Atomic mass ofoxygen)

= [2(1.0084) + 1(16.00 u)]

= 2.016 u + 16.00 u

= 18.016

= 18.02 u

(ii) CO2:

The molecular mass of carbon dioxide, CO2

= (1 × Atomic mass of carbon) + (2 × Atomic mass ofoxygen)

= [1(12.011 u) + 2 (16.00 u)]

= 12.011 u + 32.00 u

= 44.01 u

(iii) CH4:

The molecular mass of methane, CH4

= (1 × Atomic mass of carbon) + (4 × Atomic mass ofhydrogen)

= [1(12.011 u) + 4 (1.008 u)]

= 12.011 u + 4.032 u

= 16.043 u