A gas is held at 3.8 atm and 500 K. If the pressure is then decreased to 1.2 atm, what will the new temperature be?

1 Answer
Mar 18, 2017

The final temperature will be ~~200color(white)(.)"K"200.K.

Explanation:

This question involves Gay-Lussac's law to answer, which states that the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature.

This means that as the pressure goes up, the temperature also goes up, and vice-versa.

The equation to use is:

P_1/(T_1)=P_2/(T_2)P1T1=P2T2,

where PP is pressure in atm, and TT is temperature in Kelvins.

Given/Known Information
P_1="3.8 atm"P1=3.8 atm
T_2="500 K"T2=500 K
P_2="1.2 atm"P2=1.2 atm

Unknown: T_2T2

Solution
Rearrange the equation to isolate T_2T2.

T_2=(P_2T_1)/(P_1)T2=P2T1P1

T_2=(1.2color(red)cancel(color(black)("atm"))xx500 "K")/(3.8color(red)cancel(color(black)("atm")))~~"200 K" rounded to 1 significant figure