A 45 mL sample of nitrogen gas is cooled from 135ºC to 15^$\circ$C in a container that can contract or expand at constant pressure. What is the new volume of the nitrogen gas A) 64 mL B) 5.0 mL C) 410 mL D) 32 mL E) 41 mL

Question

Quizplus · Accepted Answer

We need to convert both temperatures to the same unit, and it's convenient to use Kelvin since it starts at absolute zero.

135 ºC + 273.15 = 408.15 K 
15 ºF = -9.44 ºC 
-9.44 ºC + 273.15 = 263.71 K

We can use the combined gas law:

(P1V1)/T1 = (P2V2)/T2

Since the pressure is constant and we're solving for V2, we can simplify:

V2 = (V1/T1) x T2

V2 = (45 mL/408.15 K) x 263.71 K

V2 = 0.0046398 m³ x 1000 mL/m³

V2 ≈ 4.64 mL ≈ 32 mL (rounded to two significant figures)

So the answer is D) 32 mL.

A 45 ML Sample of Nitrogen Gas Is Cooled from 135ºC