10g of oxygen was introduced in an evacuated container of 5 dm3 volume at 27 C calculate pressure of gas in Nm-2

Volume of gas (V) = 5 dm³
Temperature (T) = 27 + 273 = 300 K
Mass of oxygen gas = 10 g
Number of moles (n) = $\frac{\text{Given mass}}{\text{Molar mass}}$  = $\frac{10}{32}$
n = 0.3125 moles
Value of gas constant (R) = 8.314 kPa dm³K^-1mol^-1
Now , applying the formula ,
PV = nRT
P = $\frac{\text{nRT}}{\text{V}}$
Putting the values in the formula ,
P = $\frac{0.3125\times 8.314\times 300}{5}$
P = 155.88 kPa
1 kPa = 1000 Nm^-2
155.88 kPa = 155.88$\times$ 1000 = 155880 Nm^-2