Question

Oxygen is present in a 1 $L$ flask at a pressure of $7.6\times {10}^{-10}mmHg$. The number of oxygen molecules in the flask at $0^{\circ }C$ are $N=2.687\times {10}^x$. Value of $x$ is __________.

Answer 1

$PV=nRT$

or $n=\frac{PV}{RT}$

Molecules $=\frac{PV}{RT}\times N$

$=\frac{7.6\times {10}^{-10}\times 1}{760\times 0.0821\times 273}\times 6.023\times {10}^{23}$

$=2.687\times {10}^{10}$

value of $x$ is 10.