Ten grams of a gas occupies 12.5 liters at a pressure of 42.0 cm Hg. What is the volume when the pressure has increased to 75.0 cm Hg?

1 Answer
Oct 13, 2016

Answer:

At constant temperature, and constant amount of gas, #P_1V_1=P_2V_2#.

Explanation:

So all we have to do is convert the #cm*Hg# into a pressure reading, and calculate #V_2#.

#1*atm-=760*mm*Hg#; of course, given the relationship the units of pressure cancel out.

#V_2=(P_1V_1)/P_2# #=# #(12.5*Lxx420*mm*Hg)/(750*mm*Hg)# #~=# #7*L#.

Note that here we use a unit of length to measure the pressure. That is #1*atm# will support a column of mercury that is #760*mm# high. Ordinarily, you would be expected to calculate the pressure with authentic units of #kPa# or #"atmospheres"#. Here, we can afford to be a little slack.