Chemistry hw Help

Question

A gas is initially at STP, calculate the final temperature if the pressure changed to 199KPa. Name the law used

Answer 1

Standard Temperature and Pressure (STP) is a temperature of 273K and a pressure or 1 atm.

Since no volume is given, we assume it to be constant and use Gay-Lussac's Law:

P1/T1 = P2/T2

P1 = 1 atm

T1 = 273K

P2 = 199kPa x 1 atm/101.325 kPa = 1.964 atm (converted kPa to atm)

T2 = ?

T2 = P2T1 / P1 = 1.964 atm x 273K / 1 atm = 536K

If you prefer not to convert kPa to atm, you can solve using 101.325 at the standard pressure (P1)

T2 = 199 kPa x 273K / 101.325 kPa = 536K