Question

A plant virus is found to consist of uniform cylindrical particle of $150$ Angstrom in diameter and $5000$ Angstrom long. The specific volume of the virus is $0.75mL{g}^{-1}$. if the virus is considered to be a single particle, find its molar mass.

• A. $7.092\times {10}^{7}g$
• B. $7.092\times {10}^{3}g$
• C. $7.092\times {10}^{9}g$
• D. None

Answer 1

The correct option is A $7.092\times {10}^{7}g$

Percentage loss in mass$=2\times \frac{18}{266.5}\times 100=13.50\%$
Specific volume $=\frac{Volume}{Mass}$
Mass$=\frac{\pi r^{2}h}{Specificvolume}$ $=\frac{3.14\times (75\times {10}^{-8}{)}^2\times 5000\times {10}^{-8}}{0.75}$
Molar mass$=Mass\times N$ $=\frac{3.14\times (75\times {10}^{-8}{)}^2\times 5000\times {10}^{-8}}{0.5}\times 6.023\times {10}^{23}$ $=7.092\times {10}^{7}g$