A 150 ml sample of gas is at 620 mm Hg. The volume is decreased to 100 ml at a constant temperature. What is the new pressure of gas ? How would you set this up to solve it , and what is the answer ?

1 Answer
May 22, 2018

Answer:

Well, #1*atm# will support a column of mercury that is #760*mm# high....

Explanation:

And so we gots a #150*mL# volume of gas at #(620*mm*Hg)/(760*mm*Hg*atm^-1)=0.816*atm#..

And old Boyle's law holds that #P_1V_1=P_2V_2# for a given mass of gas....

And so #P_2=(P_1V_1)/V_2=(0.816*atmxx150*mL)/(100*mL)=1.22*atm#...

I changed the pressure to atmospheres because I would not accept a pressure OVER #1*atm# that quoted a measurement in #mm*Hg#. Units of #mm*Hg# are used for ONE atmosphere or BELOW, and it is inappropriate to use them in scenarios where #P">>"1*atm#....