Question

a sample of gas has an initial volume of 14.0 l at a pressure of 1.41 atm . part a if the sample is compressed to a volume of 10.5 l , what is its pressure? express the pressure in atmospheres to three significant figures.

Answer 1

Step-by-step explanation:

We can use the combined gas law.

P1V1T1 = P2V2T2

where P, V, and T are the pressures, volumes and temperatures for the initial (P1,V1,T1) and final (P2,V2,T2) states. All temperatures must be in Kelvin (add 273,15 to C to make K).

We are given volumes amd the initial pressure. Nothing is mentioned about temperatures. The unknown is the fianl pressure, P2.

Reorgamize the combined gas law to solve for P2:

P2 = P1(V1/V2)(T2/T1)

Note how the volue and temperature terms are organized. They are ratios of the starting and ending states. This helps keep things organized and easier to solve (unit cancellations are easier).

No information is given on temperatures, so we have to assume they remain constant. The term (T2/T1) reduces to 1, and the units cancel.

Enter the data:

P2 = P1(V1/V2)(T2/T1)

P2 = (1.4 atm)(14 L/10.5 L)(1)

P2 = 1.88 atm