Question

Calculate the volume at STP occupied by:
(a) 14 g of nitrogen.
(b) 1.5 moles of carbon dioxide.
(c) $10^{21}$ molecules of oxygen.

Answer 1

From the given question, in order to calculate the volume at STP, first need to identify the conditions of pressure and temperature at STP.

Note that standard temperature pressure conditions which holds temperature at 27°C and pressure at 1 atm.

Therefore, for the given subdivisions we need to calculate the volume using the ideal gas equation,

                                               PV = nRT

where, the number of moles is given the calculations are as follows

a)

$14g \quad of \quad N_{2}=\frac{1}{2} mol\quad of\quad N_{2}$

$V=\frac{nRT}{P}=\frac{1}{\times 0.0821} \times \frac{273}{1}$

  V = 11.2L

b)

$1.5\quad moles\quad of\quad CO_{2}$

$V=1.5\times 0.0821\times \frac{273}{1}$

  V= 33.62L

c)

$10^{21}$ molecules of oxygen,

1 mole = $6.023\times 10^{23}$

Therefore,

$10^{21}$ molecules will have $10^{-2}/6.023 moles$

V=$\frac{10^{-2} }{6.023} \times 0.0821\times \frac{273}{1}$

  V=0.037L