5.1 Ideal gas law and general gas equation  (Page 2/4)

1 mole of nitrogen (N ${}_2$ ) reacts with hydrogen (H ${}_2$ ) according to the following equation:

The ammonia (NH ${}_3$ ) gas is collected in a separate gas cylinder which has a volume of 25 dm ${}^3$ . The temperature of the gas is 22 ${}^{\circ }$ C. Calculate the pressure of the gas inside the cylinder.

Calculate the number of moles of air particles in a 10 m by 7 m by 2 m classroom on a day when the temperature is 23 ${}^{\circ }$ C and the air pressure is 98 kPa.

Most modern cars are equipped with airbags for both the driver and the passenger. An airbag will completely inflate in 0,05 s. This is important because a typical car collision lasts about 0,125 s. The following reaction of sodium azide (a compound found in airbags) is activated by an electrical signal:

$2Na{N}_3\left(s\right)\to 2Na\left(s\right)+3N_2\left(g\right)$

1. Calculate the mass of $N_2\left(g\right)$ needed to inflate a sample airbag to a volume of 65 dm ${}^3$ at 25 ${}^{\circ }$ C and $99,3$ kPa. Assume the gas temperature remains constant during the reaction.
2. In reality the above reaction is exothermic. Describe, in terms of the kinetic molecular theory, how the pressure in the sample airbag will change, if at all, as the gas temperature returns to 25 ${}^{\circ }$ C.