# Question #0a30f

##### 1 Answer

(a) The pressure rise in the tyre is 149 kPa. (b) The mass of air that must be bled off is 17 g.

#### Explanation:

**(a) Calculate the pressure rise.**

Since the volume is constant but the pressure and temperature are changing, this is an example of **Gay-Lussac's Law**:

#color(blue)(bar(ul(|color(white)(a/a) P_1/T_1=P_2/T_2color(white)(a/a)|)))" "#

We can rearrange the above formula to get

#P_2=P_1 × T_2/T_1#

A gauge pressure (

or

Your data are:

The new pressure is 460.1 kPa.

The pressure rise is

**(b) Calculate the mass of air to be bled off.**

For this calculation, we can use the **Ideal Gas Law**:

#color(blue)(bar(ul(|color(white)(a/a)PV = nRTcolor(white)(a/a)|)))" "#

Since

We can re-write the Ideal Gas Law as

or

Since

You would have to bleed off 17 g of air.