Question

Question #4a2ed

Answer 1

The final temperature is -149 °C.

Explanation:

Since the volume is constant, this is an example of a problem involving Gay-Lussac's Pressure-Temperature Law:

`color(blue)(bar(ul(|color(white)(a/a)p_1/T_1=p_2/T_2color(white)(a/a)|)))" "`

We can rearrange this formula to get

`T_2 = T_1 × p_2/p_1`

Your data are:

`p_1 = "450 mmHg"; T_1 = "15 °C" = "288.15 K"`
`p_2 = "225 mmHg"; T_2 = "?"`

`T_2 = "288.15 K" × (225 color(red)(cancel(color(black)("mmHg"))))/(450 color(red)(cancel(color(black)("mmHg")))) = "144.1 K" = "-129 °C"`