Question

If a gas sample has a pressure of 30.7 kPa at 0.00°C, by how much does the temperature have to decrease to lower the pressure to 28.4 kPa?

Answer 1

`T_2 = -20.5^@ "C"`

Explanation:

In this question I assume that the volume is unchanged and therefore, we can use the following law:

`P/T=k`

Then, `(P_1)/(T_1)=(P_2)/(T_2)=>T_2=(T_1)/(P_1)xxP_2`

`=>P_2=("273.15 K")/(30.7cancel("kPa"))xx28.4cancel("kPa") = "252.69 K"`

Therefore, the temperature should be lowered to: `252.69 - 273.15 = - 20.464^@ "C"`

`=> color(blue)(T_2 = -20.5^@"C")` to 3 sig figs.