Question

1.1
Calculate the molar mass of the following
(i) H,O (ii) CO, (iii) CH,
C​

Answer 1

Answer:

(i) H2O

The molecular mass of water, H2O

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

Use Appendix II of NCERT book at page 232

= [2(1.0079) + 1(16.00)]

= 2.016 + 16.00

= 18.016

Approximate the value

= 18.02 amu

(ii) CO2

The molecular mass of carbon dioxide, CO2

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

Use Appendix II of NCERT book at page 232

= [1(12.01 ) + 2 (16.00 )]

= 12.01 + 32.00

= 44.01 amu

(iii) CH4

The molecular mass of methane, CH4

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

Use Appendix II of NCERT book at page 232

= [1(12.01) + 4 (1.0079 )]

= 12.01 + 4.032

= 16.04 amu

Explanation:

Hope it helps