Question

Calculate the molar mass of the following substances:

(a) Ethyne,C₂H₂
(b) Sulphur molecule,S₈
(c) Nitric acid,HNO₃

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Answer 1

Answer:

(a) Ethyne (C

2

H

2

) = 2×Mass of C atom+2×Mass of H atom=2×12+2×1=24+2=26 g/mol

(b) Sulphur dioxide (S

8

)=8×Mass of sulphur atom=8×32=256 g/mol

(c) P

4

=4×Mass of P atom=4×31=124 g/mol

(d) HCl=1×Mass of H atom+1×Mass of Cl atom=1+35.5=36.5 g/mol

(e) HNO

3

=1×Mass of H atom+1×Mass of N atom+3×Mass of O atom

=1×1+1×14+3×16=63 g/mol