Calculate the moles of Hydrogen present in a 500 cmଷ sample of hydrogen gas at a pressure of 760 mm of Hg and27°C

First we should convert the given data into suitable units of ideal gas equation.

volume,$\mathrm{V}=500{\mathrm{cm}}^3$

$=\frac{500{\mathrm{cm}}^3}{1000 {\mathrm{cm}}^3}\times 1.0L$

=0.500 L

Pressure ,P =760 mm of Hg$=\frac{760 \mathrm{mm} \mathrm{of} \mathrm{hg}}{760 \mathrm{mm} \mathrm{of} \mathrm{hg}}\times 1 \mathrm{atm} \left[1 \mathrm{atm}= 760 \mathrm{mm} \mathrm{of} \mathrm{hg}\right]$=1.00 atm

Temperature , T = 27$°\mathrm{C}$

So, T  in Kelvin = °C + 273

=  27  +  273

= 300 k

Universal gas constant , R = 0.0821 L.atm /mol.K

From ideal gas equation.

$\mathrm{n}=\frac{\mathrm{pv}}{\mathrm{RT}}$

$=\frac{1.00\times 0.500}{0.0821\times 300}$

$=2.03\times {10}^{-2}\mathrm{mol}$

The number of moles of Hydrogen gas present in $500 {\mathrm{cm}}^3$  sample of Hydrogen gas at a pressure of 760 mm of Hg and 27°C is $2.03\times {10}^{-2}\mathrm{mol}$