Arigid, 2.50 l bottle contains 0.458 mol he. the pressure of the gas inside the bottle is 1.83 atm. if 0.713 mol ar is added to the bottle and the pressure increases to 2.05 atm, what is the change in temperature of the gas mixture? the initial temperature of the gas is 122 k. the final temperature of the gas is k.

137 K

The volume is constant, so you can use Gay-Lussac’s Pressure-Temperature Law to calculate the new temperature (you don’t have to use the number of moles).

P1/T1 = P2/T2

Solve for T2: T2= T1 x P2/P1

P1 = 1.83 atm; T1 = 122 K

P2 = 2.05 atm; T2 = ?

∴ T2 = 122 K x (2.05 atm)/(1.83 atm) = 137 K

This result makes sense. Temperature is directly proportional to pressure. You increased the pressure by about 10 %, so the temperature increased by about 10 %.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.