Question

What is the molecular mass of a substance, each molecule of which contains 9 carbon atoms, 13 hydrogen atoms and $2.33\times {10}^{-23}g$ of other component?

• A. 135.04
• B. 100
• C. 111
• D. 28

Answer 1

The correct option is A 135.04

The molecule has C, H and other component. Mass of 9 C atoms =$12\times 9=108$ amu
Mass of 13 H atoms = $13\times 1=13$ amu value of 1 amu
Mass of other component = $\frac{(2.33\times {10}^{-23})}{1.66\times {10}^{-24}}=14.04$
$\therefore$ Total mass of one molecule = 108 + 13 + 14.04 = 135.04 amu
$\therefore$ Mol. mass of substance = 135.04