[ALI ALZAHRANI]

Consider a cylinder fiffed with a movable piston .the initial pressure inside the cylinder is Pi and the initial volume is Vi .what is the new pressure in the system when the piston decreases the volume of the cylinder by one third

At constant temperature (isothermal) situation

P1V1 = P2V2

but V2 =(1/3) V1 =(1/3) Vi

P2 = P1V1/V2 = PiVi/(1/3)Vi = 3Pi

الاختـيـآر 4
3Pi

it is desired to increase the volume of a sample of neon gas from 90.0 to 115 cm3 while holding the pressure constant .If the initial temperature is 23c .what must the final temperature (c) be

At constant pressure (isobaric) situation

V1/V2 = T1/T2

T1 =23 +273 =296 K

T2 =(V2/V1) T1 =(115/90)*296 =378 K

T2 = 378 -273 =105 C

الاختيـآر 5
105

A 0.50 L container is occupied by nitrogen at a pressure of 800 torr and a temperature of 0c . the container can only withstand a pressure of 3.0 atm . what is the highest temperature (c) to which the container may be heated

At constant volume (isochoric) situation

T1/T2 =P1/P2

T2 = (P2/P1)T1

but 800 torr = 1.0528 atm


T2 = (3/01.0528)*273 = 778 K

T2 =778 -273=505 C

الاختيـآر 5
505